Merge pull request #15890 from smoogipoo/new-multiplayer-playlist

Implement multiplayer playlist with gameplay and historical ordering

.config/dotnet-tools.json

@@ -14,8 +14,8 @@
         "jb"
       ]
     },
-    "smoogipoo.nvika": {
-      "version": "1.0.1",
+    "nvika": {
+      "version": "2.2.0",
       "commands": [
         "nvika"
       ]
@@ -33,4 +33,4 @@
       ]
     }
   }
-}
+}

.editorconfig

@@ -113,7 +113,7 @@ dotnet_style_qualification_for_event = false:warning
 dotnet_style_predefined_type_for_locals_parameters_members = true:warning
 dotnet_style_predefined_type_for_member_access = true:warning
 csharp_style_var_when_type_is_apparent = true:none
-csharp_style_var_for_built_in_types = true:none
+csharp_style_var_for_built_in_types = false:warning
 csharp_style_var_elsewhere = true:silent
 
 #Style - modifiers

.github/FUNDING.yml

@@ -1 +1,2 @@
+github: ppy
 custom: https://osu.ppy.sh/home/support

.github/ISSUE_TEMPLATE/01-bug-issues.md

@@ -1,30 +0,0 @@
----
-name: Bug Report
-about: Report a bug or crash to desktop
----
-
-<!--
-IMPORTANT: Your issue may already be reported.
-
-Please check:
-- Pinned issues, at the top of https://github.com/ppy/osu/issues
-- Current priority 0 issues at https://github.com/ppy/osu/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc+label%3Apriority%3A0
-- Search for your issue. If you find that it already exists, please respond with a reaction or add any further information that may be helpful.
--->
-
-
-**Describe the bug:** 
-
-**Screenshots or videos showing encountered issue:** 
-
-**osu!lazer version:** 
-
-**Logs:**
-
-<!--
-*please attach logs here, which are located at:*
-- `%AppData%/osu/logs` *(on Windows),*
-- `~/.local/share/osu/logs` *(on Linux & macOS).*
-- `Android/data/sh.ppy.osulazer/files/logs` *(on Android)*,
-- on iOS they can be obtained by connecting your device to your desktop and copying the `logs` directory from the app's own document storage using iTunes. (https://support.apple.com/en-us/HT201301#copy-to-computer)
--->

.github/ISSUE_TEMPLATE/config.yml

@@ -1,12 +1,12 @@
 blank_issues_enabled: false
 contact_links:
-    - name: Suggestions or feature request
-      url: https://github.com/ppy/osu/discussions/categories/ideas
-      about: Got something you think should change or be added? Search for or start a new discussion!
     - name: Help
       url: https://github.com/ppy/osu/discussions/categories/q-a
       about: osu! not working as you'd expect? Not sure it's a bug? Check the Q&A section!
+    - name: Suggestions or feature request
+      url: https://github.com/ppy/osu/discussions/categories/ideas
+      about: Got something you think should change or be added? Search for or start a new discussion!
     - name: osu!stable issues
       url: https://github.com/ppy/osu-stable-issues
-      about: For osu!stable bugs (not osu!lazer), check out the dedicated repository. Note that we only accept serious bug reports.
+      about: For osu!(stable) - ie. the current "live" game version, check out the dedicated repository. Note that this is for serious bug reports only, not tech support.
 

.github/dependabot.yml

@@ -5,7 +5,7 @@ updates:
   schedule:
     interval: monthly
     time: "17:00"
-  open-pull-requests-limit: 99
+  open-pull-requests-limit: 0 # disabled until https://github.com/dependabot/dependabot-core/issues/369 is resolved.
   ignore:
   - dependency-name: Microsoft.EntityFrameworkCore.Design
     versions:

.github/workflows/ci.yml

@@ -50,6 +50,51 @@ jobs:
           name: osu-test-results-${{matrix.os.prettyname}}-${{matrix.threadingMode}}
           path: ${{github.workspace}}/TestResults/TestResults-${{matrix.os.prettyname}}-${{matrix.threadingMode}}.trx
 
+  build-only-android:
+    name: Build only (Android)
+    runs-on: macos-latest
+    timeout-minutes: 60
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      # Pin Xamarin.Android version to 11.2 for now to avoid build failures caused by a Xamarin-side regression.
+      # See: https://github.com/xamarin/xamarin-android/issues/6284
+      # This can be removed/reverted when the fix makes it to upstream and is deployed on github runners.
+      - name: Set default Xamarin SDK version
+        run: |
+            $VM_ASSETS/select-xamarin-sdk-v2.sh --mono=6.12 --android=11.2
+
+      - name: Install .NET 5.0.x
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: "5.0.x"
+
+      # Contrary to seemingly any other msbuild, msbuild running on macOS/Mono
+      # cannot accept .sln(f) files as arguments.
+      # Build just the main game for now.
+      - name: Build
+        run: msbuild osu.Android/osu.Android.csproj /restore /p:Configuration=Debug
+
+  build-only-ios:
+    name: Build only (iOS)
+    runs-on: macos-latest
+    timeout-minutes: 60
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Install .NET 5.0.x
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: "5.0.x"
+
+      # Contrary to seemingly any other msbuild, msbuild running on macOS/Mono
+      # cannot accept .sln(f) files as arguments.
+      # Build just the main game for now.
+      - name: Build
+        run: msbuild osu.iOS/osu.iOS.csproj /restore /p:Configuration=Debug
+
   inspect-code:
     name: Code Quality
     runs-on: ubuntu-latest
@@ -79,9 +124,14 @@ jobs:
         run: |
           # TODO: Add ignore filters and GitHub Workflow Command Reporting in CFS. That way we don't have to do this workaround.
           # FIXME: Suppress warnings from templates project
-          dotnet codefilesanity | while read -r line; do
-            echo "::warning::$line"
-          done
+          exit_code=0
+          while read -r line; do
+            if [[ ! -z "$line" ]]; then
+              echo "::error::$line"
+              exit_code=1
+            fi
+          done <<< $(dotnet codefilesanity)
+          exit $exit_code
 
       # Temporarily disabled due to test failures, but it won't work anyway until the tool is upgraded.
       # - name: .NET Format (Dry Run)

.github/workflows/diffcalc.yml

@@ -0,0 +1,206 @@
+# Listens for new PR comments containing !pp check [id], and runs a diffcalc comparison against master.
+# Usage:
+#   !pp check 0        | Runs only the osu! ruleset.
+#   !pp check 0 2      | Runs only the osu! and catch rulesets.
+#
+
+name: Difficulty Calculation
+on:
+  issue_comment:
+    types: [ created ]
+
+env:
+  CONCURRENCY: 4
+  ALLOW_DOWNLOAD: 1
+  SAVE_DOWNLOADED: 1
+  SKIP_INSERT_ATTRIBUTES: 1
+
+jobs:
+  metadata:
+    name: Check for requests
+    runs-on: self-hosted
+    if: github.event.issue.pull_request && contains(github.event.comment.body, '!pp check') && (github.event.comment.author_association == 'MEMBER' || github.event.comment.author_association == 'OWNER')
+    outputs:
+      matrix: ${{ steps.generate-matrix.outputs.matrix }}
+      continue: ${{ steps.generate-matrix.outputs.continue }}
+    steps:
+      - name: Construct build matrix
+        id: generate-matrix
+        run: |
+          if [[ "${{ github.event.comment.body }}" =~ "osu" ]] ; then
+            MATRIX_PROJECTS_JSON+='{ "name": "osu", "id": 0 },'
+          fi
+          if [[ "${{ github.event.comment.body }}" =~ "taiko" ]] ; then
+            MATRIX_PROJECTS_JSON+='{ "name": "taiko", "id": 1 },'
+          fi
+          if [[ "${{ github.event.comment.body }}" =~ "catch" ]] ; then
+            MATRIX_PROJECTS_JSON+='{ "name": "catch", "id": 2 },'
+          fi
+          if [[ "${{ github.event.comment.body }}" =~ "mania" ]] ; then
+            MATRIX_PROJECTS_JSON+='{ "name": "mania", "id": 3 },'
+          fi
+
+          if [[ "${MATRIX_PROJECTS_JSON}" != "" ]]; then
+            MATRIX_JSON="{ \"ruleset\": [ ${MATRIX_PROJECTS_JSON} ] }"
+            echo "${MATRIX_JSON}"
+            CONTINUE="yes"
+          else
+            CONTINUE="no"
+          fi
+
+          echo "::set-output name=continue::${CONTINUE}"
+          echo "::set-output name=matrix::${MATRIX_JSON}"
+  diffcalc:
+    name: Run
+    runs-on: self-hosted
+    timeout-minutes: 1440
+    if: needs.metadata.outputs.continue == 'yes'
+    needs: metadata
+    strategy:
+      matrix: ${{ fromJson(needs.metadata.outputs.matrix) }}
+    steps:
+      - name: Verify MySQL connection from host
+        run: |
+          mysql -e "SHOW DATABASES"
+
+      - name: Drop previous databases
+        run: |
+          for db in osu_master osu_pr
+          do
+            mysql -e "DROP DATABASE IF EXISTS $db"
+          done
+
+      - name: Create directory structure
+        run: |
+          mkdir -p $GITHUB_WORKSPACE/master/
+          mkdir -p $GITHUB_WORKSPACE/pr/
+
+      - name: Get upstream branch # https://akaimo.hatenablog.jp/entry/2020/05/16/101251
+        id: upstreambranch
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          echo "::set-output name=branchname::$(curl -H "Authorization: token ${GITHUB_TOKEN}" ${{ github.event.issue.pull_request.url }} | jq '.head.ref' | sed 's/\"//g')"
+          echo "::set-output name=repo::$(curl -H "Authorization: token ${GITHUB_TOKEN}" ${{ github.event.issue.pull_request.url }} | jq '.head.repo.full_name' | sed 's/\"//g')"
+
+      # Checkout osu
+      - name: Checkout osu (master)
+        uses: actions/checkout@v2
+        with:
+          path: 'master/osu'
+      - name: Checkout osu (pr)
+        uses: actions/checkout@v2
+        with:
+          path: 'pr/osu'
+          repository: ${{ steps.upstreambranch.outputs.repo }}
+          ref: ${{ steps.upstreambranch.outputs.branchname }}
+
+      - name: Checkout osu-difficulty-calculator (master)
+        uses: actions/checkout@v2
+        with:
+          repository: ppy/osu-difficulty-calculator
+          path: 'master/osu-difficulty-calculator'
+      - name: Checkout osu-difficulty-calculator (pr)
+        uses: actions/checkout@v2
+        with:
+          repository: ppy/osu-difficulty-calculator
+          path: 'pr/osu-difficulty-calculator'
+
+      - name: Install .NET 5.0.x
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: "5.0.x"
+
+      # Sanity checks to make sure diffcalc is not run when incompatible.
+      - name: Build diffcalc (master)
+        run: |
+          cd $GITHUB_WORKSPACE/master/osu-difficulty-calculator
+          ./UseLocalOsu.sh
+          dotnet build
+      - name: Build diffcalc (pr)
+        run: |
+          cd $GITHUB_WORKSPACE/pr/osu-difficulty-calculator
+          ./UseLocalOsu.sh
+          dotnet build
+
+      - name: Download + import data
+        run: |
+          PERFORMANCE_DATA_NAME=$(curl https://data.ppy.sh/ | grep performance_${{ matrix.ruleset.name }}_top_1000 | tail -1 | awk -F "\"" '{print $2}' | sed 's/\.tar\.bz2//g')
+          BEATMAPS_DATA_NAME=$(curl https://data.ppy.sh/ | grep osu_files | tail -1 | awk -F "\"" '{print $2}' | sed 's/\.tar\.bz2//g')
+
+          # Set env variable for further steps.
+          echo "BEATMAPS_PATH=$GITHUB_WORKSPACE/$BEATMAPS_DATA_NAME" >> $GITHUB_ENV
+
+          cd $GITHUB_WORKSPACE
+
+          echo "Downloading database dump $PERFORMANCE_DATA_NAME.."
+          wget -q -nc https://data.ppy.sh/$PERFORMANCE_DATA_NAME.tar.bz2
+          echo "Extracting.."
+          tar -xf $PERFORMANCE_DATA_NAME.tar.bz2
+
+          echo "Downloading beatmap dump $BEATMAPS_DATA_NAME.."
+          wget -q -nc https://data.ppy.sh/$BEATMAPS_DATA_NAME.tar.bz2
+          echo "Extracting.."
+          tar -xf $BEATMAPS_DATA_NAME.tar.bz2
+
+          cd $PERFORMANCE_DATA_NAME
+
+          for db in osu_master osu_pr
+          do
+            echo "Setting up database $db.."
+
+            mysql -e "CREATE DATABASE $db"
+
+            echo "Importing beatmaps.."
+            cat osu_beatmaps.sql | mysql $db
+            echo "Importing beatmapsets.."
+            cat osu_beatmapsets.sql | mysql $db
+
+            echo "Creating table structure.."
+            mysql $db -e 'CREATE TABLE `osu_beatmap_difficulty` (
+                `beatmap_id` int unsigned NOT NULL,
+                `mode` tinyint NOT NULL DEFAULT 0,
+                `mods` int unsigned NOT NULL,
+                `diff_unified` float NOT NULL,
+                `last_update` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+                PRIMARY KEY (`beatmap_id`,`mode`,`mods`),
+                KEY `diff_sort` (`mode`,`mods`,`diff_unified`)
+              ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;'
+          done
+
+      - name: Run diffcalc (master)
+        env:
+          DB_NAME: osu_master
+        run: |
+          cd $GITHUB_WORKSPACE/master/osu-difficulty-calculator/osu.Server.DifficultyCalculator
+          dotnet run -c:Release -- all -m ${{ matrix.ruleset.id }} -ac -c ${{ env.CONCURRENCY }}
+      - name: Run diffcalc (pr)
+        env:
+          DB_NAME: osu_pr
+        run: |
+          cd $GITHUB_WORKSPACE/pr/osu-difficulty-calculator/osu.Server.DifficultyCalculator
+          dotnet run -c:Release -- all -m ${{ matrix.ruleset.id }} -ac -c ${{ env.CONCURRENCY }}
+
+      - name: Print diffs
+        run: |
+          mysql -e "
+            SELECT
+              m.beatmap_id,
+              m.mods,
+              b.filename,
+              m.diff_unified as 'sr_master',
+              p.diff_unified as 'sr_pr',
+              (p.diff_unified - m.diff_unified) as 'diff'
+            FROM osu_master.osu_beatmap_difficulty m
+            JOIN osu_pr.osu_beatmap_difficulty p
+              ON m.beatmap_id = p.beatmap_id
+              AND m.mode = p.mode
+              AND m.mods = p.mods
+            JOIN osu_pr.osu_beatmaps b
+              ON b.beatmap_id = p.beatmap_id
+            WHERE abs(m.diff_unified - p.diff_unified) > 0.1
+            ORDER BY abs(m.diff_unified - p.diff_unified)
+              DESC
+            LIMIT 10000;"
+
+      # Todo: Run ppcalc

.github/workflows/report-nunit.yml

@@ -30,3 +30,5 @@ jobs:
           name: Test Results (${{matrix.os.prettyname}}, ${{matrix.threadingMode}})
           path: "*.trx"
           reporter: dotnet-trx
+          list-suites: 'failed'
+          list-tests: 'failed'

.github/workflows/test-diffcalc.yml

@@ -1,163 +0,0 @@
-# Listens for new PR comments containing !pp check [id], and runs a diffcalc comparison against master.
-# Usage:
-#   !pp check 0        | Runs only the osu! ruleset.
-#   !pp check 0 2      | Runs only the osu! and catch rulesets.
-#
-
-name: Diffcalc Consistency Checks
-on:
-  issue_comment:
-    types: [ created ]
-
-env:
-  DB_USER: root
-  DB_HOST: 127.0.0.1
-  CONCURRENCY: 4
-  ALLOW_DOWNLOAD: 1
-  SAVE_DOWNLOADED: 1
-
-jobs:
-  diffcalc:
-    name: Diffcalc
-    runs-on: ubuntu-latest
-    continue-on-error: true
-
-    if: |
-      github.event.issue.pull_request &&
-      contains(github.event.comment.body, '!pp check') &&
-      (github.event.comment.author_association == 'MEMBER' || github.event.comment.author_association == 'OWNER')
-
-    strategy:
-      fail-fast: false
-      matrix:
-        ruleset:
-          - { name: osu, id: 0 }
-          - { name: taiko, id: 1 }
-          - { name: catch, id: 2 }
-          - { name: mania, id: 3 }
-
-    services:
-      mysql:
-        image: mysql:8.0
-        env:
-          MYSQL_ALLOW_EMPTY_PASSWORD: yes
-        ports:
-          - 3306:3306
-        options: --health-cmd="mysqladmin ping" --health-interval=10s --health-timeout=5s --health-retries=3
-
-    steps:
-      - name: Verify ruleset
-        if: contains(github.event.comment.body, matrix.ruleset.id) == false
-        run: |
-          echo "${{ github.event.comment.body }} doesn't contain ${{ matrix.ruleset.id }}"
-          exit 1
-
-      - name: Verify MySQL connection from host
-        run: |
-          sudo apt-get install -y mysql-client
-          mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} -e "SHOW DATABASES"
-
-      - name: Create directory structure
-        run: |
-          mkdir -p $GITHUB_WORKSPACE/master/
-          mkdir -p $GITHUB_WORKSPACE/pr/
-
-      # Checkout osu
-      - name: Checkout osu (master)
-        uses: actions/checkout@v2
-        with:
-          repository: ppy/osu
-          path: 'master/osu'
-      - name: Checkout osu (pr)
-        uses: actions/checkout@v2
-        with:
-          path: 'pr/osu'
-
-      # Checkout osu-difficulty-calculator
-      - name: Checkout osu-difficulty-calculator (master)
-        uses: actions/checkout@v2
-        with:
-          repository: ppy/osu-difficulty-calculator
-          path: 'master/osu-difficulty-calculator'
-      - name: Checkout osu-difficulty-calculator (pr)
-        uses: actions/checkout@v2
-        with:
-          repository: ppy/osu-difficulty-calculator
-          path: 'pr/osu-difficulty-calculator'
-
-      - name: Install .NET 5.0.x
-        uses: actions/setup-dotnet@v1
-        with:
-          dotnet-version: "5.0.x"
-
-      # Sanity checks to make sure diffcalc is not run when incompatible.
-      - name: Build diffcalc (master)
-        run: |
-          cd $GITHUB_WORKSPACE/master/osu-difficulty-calculator
-          ./UseLocalOsu.sh
-          dotnet build
-      - name: Build diffcalc (pr)
-        run: |
-          cd $GITHUB_WORKSPACE/pr/osu-difficulty-calculator
-          ./UseLocalOsu.sh
-          dotnet build
-
-      # Initial data imports
-      - name: Download + import data
-        run: |
-          PERFORMANCE_DATA_NAME=$(curl https://data.ppy.sh/ | grep performance_${{ matrix.ruleset.name }}_top | tail -1 | awk -F "\"" '{print $2}' | sed 's/\.tar\.bz2//g')
-          BEATMAPS_DATA_NAME=$(curl https://data.ppy.sh/ | grep osu_files | tail -1 | awk -F "\"" '{print $2}' | sed 's/\.tar\.bz2//g')
-
-          # Set env variable for further steps.
-          echo "BEATMAPS_PATH=$GITHUB_WORKSPACE/$BEATMAPS_DATA_NAME" >> $GITHUB_ENV
-
-          cd $GITHUB_WORKSPACE
-
-          wget https://data.ppy.sh/$PERFORMANCE_DATA_NAME.tar.bz2
-          wget https://data.ppy.sh/$BEATMAPS_DATA_NAME.tar.bz2
-          tar -xf $PERFORMANCE_DATA_NAME.tar.bz2
-          tar -xf $BEATMAPS_DATA_NAME.tar.bz2
-
-          cd $GITHUB_WORKSPACE/$PERFORMANCE_DATA_NAME
-
-          mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} -e "CREATE DATABASE osu_master"
-          mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} -e "CREATE DATABASE osu_pr"
-
-          cat *.sql | mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} --database=osu_master
-          cat *.sql | mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} --database=osu_pr
-
-      # Run diffcalc
-      - name: Run diffcalc (master)
-        env:
-          DB_NAME: osu_master
-        run: |
-          cd $GITHUB_WORKSPACE/master/osu-difficulty-calculator/osu.Server.DifficultyCalculator
-          dotnet run -c:Release -- all -m ${{ matrix.ruleset.id }} -ac -c ${{ env.CONCURRENCY }}
-      - name: Run diffcalc (pr)
-        env:
-          DB_NAME: osu_pr
-        run: |
-          cd $GITHUB_WORKSPACE/pr/osu-difficulty-calculator/osu.Server.DifficultyCalculator
-          dotnet run -c:Release -- all -m ${{ matrix.ruleset.id }} -ac -c ${{ env.CONCURRENCY }}
-
-      # Print diffs
-      - name: Print diffs
-        run: |
-          mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} -e "
-            SELECT
-              m.beatmap_id,
-              m.mods,
-              m.diff_unified as 'sr_master',
-              p.diff_unified as 'sr_pr',
-              (p.diff_unified - m.diff_unified) as 'diff'
-            FROM osu_master.osu_beatmap_difficulty m
-            JOIN osu_pr.osu_beatmap_difficulty p
-              ON m.beatmap_id = p.beatmap_id
-              AND m.mode = p.mode
-              AND m.mods = p.mods
-            WHERE abs(m.diff_unified - p.diff_unified) > 0.1
-            ORDER BY abs(m.diff_unified - p.diff_unified)
-              DESC
-            LIMIT 10000;"
-
-      # Todo: Run ppcalc

.idea/.idea.osu.iOS/.idea/.name

@@ -0,0 +1 @@
+osu.iOS

.idea/.idea.osu.iOS/.idea/indexLayout.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="UserContentModel">
+    <attachedFolders />
+    <explicitIncludes />
+    <explicitExcludes />
+  </component>
+</project>

.idea/.idea.osu.iOS/.idea/misc.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="com.jetbrains.rider.android.RiderAndroidMiscFileCreationComponent">
+    <option name="ENSURE_MISC_FILE_EXISTS" value="true" />
+  </component>
+</project>

.idea/.idea.osu.iOS/.idea/projectSettingsUpdater.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RiderProjectSettingsUpdater">
+    <option name="vcsConfiguration" value="2" />
+  </component>
+</project>

.idea/.idea.osu.iOS/.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

.idea/.idea.osu/.idea/indexLayout.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ContentModelUserStore">
+  <component name="UserContentModel">
     <attachedFolders />
     <explicitIncludes />
     <explicitExcludes />

CodeAnalysis/BannedSymbols.txt

@@ -8,4 +8,8 @@ M:osu.Framework.Graphics.Sprites.SpriteText.#ctor;Use OsuSpriteText.
 M:osu.Framework.Bindables.IBindableList`1.GetBoundCopy();Fails on iOS. Use manual ctor + BindTo instead. (see https://github.com/mono/mono/issues/19900)
 T:Microsoft.EntityFrameworkCore.Internal.EnumerableExtensions;Don't use internal extension methods.
 T:Microsoft.EntityFrameworkCore.Internal.TypeExtensions;Don't use internal extension methods.
-M:System.Enum.HasFlag(System.Enum);Use osu.Framework.Extensions.EnumExtensions.HasFlagFast<T>() instead.
+T:NuGet.Packaging.CollectionExtensions;Don't use internal extension methods.
+M:System.Enum.HasFlag(System.Enum);Use osu.Framework.Extensions.EnumExtensions.HasFlagFast<T>() instead.
+M:Realms.IRealmCollection`1.SubscribeForNotifications`1(Realms.NotificationCallbackDelegate{``0});Use osu.Game.Database.RealmObjectExtensions.QueryAsyncWithNotifications(IRealmCollection<T>,NotificationCallbackDelegate<T>) instead.
+M:Realms.CollectionExtensions.SubscribeForNotifications`1(System.Linq.IQueryable{``0},Realms.NotificationCallbackDelegate{``0});Use osu.Game.Database.RealmObjectExtensions.QueryAsyncWithNotifications(IQueryable<T>,NotificationCallbackDelegate<T>) instead.
+M:Realms.CollectionExtensions.SubscribeForNotifications`1(System.Collections.Generic.IList{``0},Realms.NotificationCallbackDelegate{``0});Use osu.Game.Database.RealmObjectExtensions.QueryAsyncWithNotifications(IList<T>,NotificationCallbackDelegate<T>) instead.

Directory.Build.props

@@ -16,7 +16,7 @@
     <EmbeddedResource Include="Resources\**\*.*" />
   </ItemGroup>
   <ItemGroup Label="Code Analysis">
-    <PackageReference Include="Microsoft.CodeAnalysis.BannedApiAnalyzers" Version="3.3.2" PrivateAssets="All" />
+    <PackageReference Include="Microsoft.CodeAnalysis.BannedApiAnalyzers" Version="3.3.3" PrivateAssets="All" />
     <AdditionalFiles Include="$(MSBuildThisFileDirectory)CodeAnalysis\BannedSymbols.txt" />
     <PackageReference Include="Microsoft.CodeAnalysis.NetAnalyzers" Version="5.0.3" PrivateAssets="All" />
   </ItemGroup>

Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform.Tests/osu.Game.Rulesets.EmptyFreeform.Tests.csproj

@@ -10,9 +10,9 @@
     </PropertyGroup>
   <ItemGroup Label="Package References">
     <PackageReference Include="Appveyor.TestLogger" Version="2.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
     <PackageReference Include="NUnit" Version="3.13.2" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.1.0" />
     <PackageReference Update="Microsoft.EntityFrameworkCore.Sqlite" Version="2.1.4" />
   </ItemGroup>
   <ItemGroup>

Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformDifficultyCalculator.cs

@@ -13,14 +13,14 @@ namespace osu.Game.Rulesets.EmptyFreeform
 {
     public class EmptyFreeformDifficultyCalculator : DifficultyCalculator
     {
-        public EmptyFreeformDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public EmptyFreeformDifficultyCalculator(IRulesetInfo ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
 
         protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
         {
-            return new DifficultyAttributes(mods, skills, 0);
+            return new DifficultyAttributes(mods, 0);
         }
 
         protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate) => Enumerable.Empty<DifficultyHitObject>();

Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformRuleset.cs

@@ -30,8 +30,8 @@ namespace osu.Game.Rulesets.EmptyFreeform
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) =>
             new EmptyFreeformBeatmapConverter(beatmap, this);
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) =>
-            new EmptyFreeformDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) =>
+            new EmptyFreeformDifficultyCalculator(RulesetInfo, beatmap);
 
         public override IEnumerable<Mod> GetModsFor(ModType type)
         {

Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/Mods/EmptyFreeformModAutoplay.cs

@@ -3,10 +3,10 @@
 
 using System.Collections.Generic;
 using osu.Game.Beatmaps;
+using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Rulesets.EmptyFreeform.Replays;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Scoring;
-using osu.Game.Users;
 
 namespace osu.Game.Rulesets.EmptyFreeform.Mods
 {
@@ -16,7 +16,7 @@ namespace osu.Game.Rulesets.EmptyFreeform.Mods
         {
             ScoreInfo = new ScoreInfo
             {
-                User = new User { Username = "sample" },
+                User = new APIUser { Username = "sample" },
             },
             Replay = new EmptyFreeformAutoGenerator(beatmap).Generate(),
         };

Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon.Tests/osu.Game.Rulesets.Pippidon.Tests.csproj

@@ -10,9 +10,9 @@
   </PropertyGroup>
   <ItemGroup Label="Package References">
     <PackageReference Include="Appveyor.TestLogger" Version="2.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
     <PackageReference Include="NUnit" Version="3.13.2" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.1.0" />
     <PackageReference Update="Microsoft.EntityFrameworkCore.Sqlite" Version="2.1.4" />
   </ItemGroup>
   <ItemGroup>

Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/Mods/PippidonModAutoplay.cs

@@ -3,10 +3,10 @@
 
 using System.Collections.Generic;
 using osu.Game.Beatmaps;
+using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Pippidon.Replays;
 using osu.Game.Scoring;
-using osu.Game.Users;
 
 namespace osu.Game.Rulesets.Pippidon.Mods
 {
@@ -16,7 +16,7 @@ namespace osu.Game.Rulesets.Pippidon.Mods
         {
             ScoreInfo = new ScoreInfo
             {
-                User = new User { Username = "sample" },
+                User = new APIUser { Username = "sample" },
             },
             Replay = new PippidonAutoGenerator(beatmap).Generate(),
         };

Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs

@@ -13,14 +13,14 @@ namespace osu.Game.Rulesets.Pippidon
 {
     public class PippidonDifficultyCalculator : DifficultyCalculator
     {
-        public PippidonDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public PippidonDifficultyCalculator(IRulesetInfo ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
 
         protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
         {
-            return new DifficultyAttributes(mods, skills, 0);
+            return new DifficultyAttributes(mods, 0);
         }
 
         protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate) => Enumerable.Empty<DifficultyHitObject>();

Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonRuleset.cs

@@ -26,8 +26,8 @@ namespace osu.Game.Rulesets.Pippidon
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) =>
             new PippidonBeatmapConverter(beatmap, this);
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) =>
-            new PippidonDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) =>
+            new PippidonDifficultyCalculator(RulesetInfo, beatmap);
 
         public override IEnumerable<Mod> GetModsFor(ModType type)
         {

Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling.Tests/osu.Game.Rulesets.EmptyScrolling.Tests.csproj

@@ -10,9 +10,9 @@
   </PropertyGroup>
   <ItemGroup Label="Package References">
     <PackageReference Include="Appveyor.TestLogger" Version="2.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
     <PackageReference Include="NUnit" Version="3.13.2" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.1.0" />
     <PackageReference Update="Microsoft.EntityFrameworkCore.Sqlite" Version="2.1.4" />
   </ItemGroup>
   <ItemGroup>

Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingDifficultyCalculator.cs

@@ -13,14 +13,14 @@ namespace osu.Game.Rulesets.EmptyScrolling
 {
     public class EmptyScrollingDifficultyCalculator : DifficultyCalculator
     {
-        public EmptyScrollingDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public EmptyScrollingDifficultyCalculator(IRulesetInfo ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
 
         protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
         {
-            return new DifficultyAttributes(mods, skills, 0);
+            return new DifficultyAttributes(mods, 0);
         }
 
         protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate) => Enumerable.Empty<DifficultyHitObject>();

Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingRuleset.cs

@@ -24,7 +24,7 @@ namespace osu.Game.Rulesets.EmptyScrolling
 
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new EmptyScrollingBeatmapConverter(beatmap, this);
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new EmptyScrollingDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new EmptyScrollingDifficultyCalculator(RulesetInfo, beatmap);
 
         public override IEnumerable<Mod> GetModsFor(ModType type)
         {

Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/Mods/EmptyScrollingModAutoplay.cs

@@ -5,8 +5,8 @@ using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.EmptyScrolling.Replays;
 using osu.Game.Scoring;
-using osu.Game.Users;
 using System.Collections.Generic;
+using osu.Game.Online.API.Requests.Responses;
 
 namespace osu.Game.Rulesets.EmptyScrolling.Mods
 {
@@ -16,7 +16,7 @@ namespace osu.Game.Rulesets.EmptyScrolling.Mods
         {
             ScoreInfo = new ScoreInfo
             {
-                User = new User { Username = "sample" },
+                User = new APIUser { Username = "sample" },
             },
             Replay = new EmptyScrollingAutoGenerator(beatmap).Generate(),
         };

Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon.Tests/osu.Game.Rulesets.Pippidon.Tests.csproj

@@ -10,9 +10,9 @@
   </PropertyGroup>
   <ItemGroup Label="Package References">
     <PackageReference Include="Appveyor.TestLogger" Version="2.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
     <PackageReference Include="NUnit" Version="3.13.2" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.1.0" />
     <PackageReference Update="Microsoft.EntityFrameworkCore.Sqlite" Version="2.1.4" />
   </ItemGroup>
   <ItemGroup>

Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/Mods/PippidonModAutoplay.cs

@@ -3,10 +3,10 @@
 
 using System.Collections.Generic;
 using osu.Game.Beatmaps;
+using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Pippidon.Replays;
 using osu.Game.Scoring;
-using osu.Game.Users;
 
 namespace osu.Game.Rulesets.Pippidon.Mods
 {
@@ -16,7 +16,7 @@ namespace osu.Game.Rulesets.Pippidon.Mods
         {
             ScoreInfo = new ScoreInfo
             {
-                User = new User { Username = "sample" },
+                User = new APIUser { Username = "sample" },
             },
             Replay = new PippidonAutoGenerator(beatmap).Generate(),
         };

Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs

@@ -13,14 +13,14 @@ namespace osu.Game.Rulesets.Pippidon
 {
     public class PippidonDifficultyCalculator : DifficultyCalculator
     {
-        public PippidonDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public PippidonDifficultyCalculator(IRulesetInfo ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
 
         protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
         {
-            return new DifficultyAttributes(mods, skills, 0);
+            return new DifficultyAttributes(mods, 0);
         }
 
         protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate) => Enumerable.Empty<DifficultyHitObject>();

Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonRuleset.cs

@@ -24,7 +24,7 @@ namespace osu.Game.Rulesets.Pippidon
 
         public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => new PippidonBeatmapConverter(beatmap, this);
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new PippidonDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new PippidonDifficultyCalculator(RulesetInfo, beatmap);
 
         public override IEnumerable<Mod> GetModsFor(ModType type)
         {

osu.Android.props

@@ -51,11 +51,11 @@
     <Reference Include="Java.Interop" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="ppy.osu.Game.Resources" Version="2021.913.0" />
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2021.916.1" />
+    <PackageReference Include="ppy.osu.Game.Resources" Version="2021.1203.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2021.1203.0" />
   </ItemGroup>
   <ItemGroup Label="Transitive Dependencies">
     <!-- Realm needs to be directly referenced in all Xamarin projects, as it will not pull in its transitive dependencies otherwise. -->
-    <PackageReference Include="Realm" Version="10.5.0" />
+    <PackageReference Include="Realm" Version="10.7.1" />
   </ItemGroup>
 </Project>

osu.Android/OsuGameActivity.cs

@@ -20,6 +20,7 @@ namespace osu.Android
     [Activity(Theme = "@android:style/Theme.NoTitleBar", MainLauncher = true, ScreenOrientation = ScreenOrientation.FullUser, SupportsPictureInPicture = false, ConfigurationChanges = ConfigChanges.Orientation | ConfigChanges.ScreenSize, HardwareAccelerated = false, LaunchMode = LaunchMode.SingleInstance, Exported = true)]
     [IntentFilter(new[] { Intent.ActionView }, Categories = new[] { Intent.CategoryDefault }, DataScheme = "content", DataPathPattern = ".*\\\\.osz", DataHost = "*", DataMimeType = "*/*")]
     [IntentFilter(new[] { Intent.ActionView }, Categories = new[] { Intent.CategoryDefault }, DataScheme = "content", DataPathPattern = ".*\\\\.osk", DataHost = "*", DataMimeType = "*/*")]
+    [IntentFilter(new[] { Intent.ActionView }, Categories = new[] { Intent.CategoryDefault }, DataScheme = "content", DataPathPattern = ".*\\\\.osr", DataHost = "*", DataMimeType = "*/*")]
     [IntentFilter(new[] { Intent.ActionView }, Categories = new[] { Intent.CategoryDefault }, DataScheme = "content", DataMimeType = "application/x-osu-beatmap-archive")]
     [IntentFilter(new[] { Intent.ActionView }, Categories = new[] { Intent.CategoryDefault }, DataScheme = "content", DataMimeType = "application/x-osu-skin-archive")]
     [IntentFilter(new[] { Intent.ActionView }, Categories = new[] { Intent.CategoryDefault }, DataScheme = "content", DataMimeType = "application/x-osu-replay")]

osu.Desktop/DiscordRichPresence.cs

@@ -11,10 +11,10 @@ using osu.Framework.Graphics;
 using osu.Framework.Logging;
 using osu.Game.Configuration;
 using osu.Game.Online.API;
+using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Rulesets;
 using osu.Game.Users;
 using LogLevel = osu.Framework.Logging.LogLevel;
-using User = osu.Game.Users.User;
 
 namespace osu.Desktop
 {
@@ -27,7 +27,7 @@ namespace osu.Desktop
         [Resolved]
         private IBindable<RulesetInfo> ruleset { get; set; }
 
-        private IBindable<User> user;
+        private IBindable<APIUser> user;
 
         private readonly IBindable<UserStatus> status = new Bindable<UserStatus>();
         private readonly IBindable<UserActivity> activity = new Bindable<UserActivity>();
@@ -108,7 +108,10 @@ namespace osu.Desktop
                 presence.Assets.LargeImageText = $"{user.Value.Username}" + (user.Value.Statistics?.GlobalRank > 0 ? $" (rank #{user.Value.Statistics.GlobalRank:N0})" : string.Empty);
 
             // update ruleset
-            presence.Assets.SmallImageKey = ruleset.Value.ID <= 3 ? $"mode_{ruleset.Value.ID}" : "mode_custom";
+            int onlineID = ruleset.Value.OnlineID;
+            bool isLegacyRuleset = onlineID >= 0 && onlineID <= ILegacyRuleset.MAX_LEGACY_RULESET_ID;
+
+            presence.Assets.SmallImageKey = isLegacyRuleset ? $"mode_{onlineID}" : "mode_custom";
             presence.Assets.SmallImageText = ruleset.Value.Name;
 
             client.SetPresence(presence);
@@ -140,10 +143,10 @@ namespace osu.Desktop
             switch (activity)
             {
                 case UserActivity.InGame game:
-                    return game.Beatmap.ToString();
+                    return game.BeatmapInfo.ToString();
 
                 case UserActivity.Editing edit:
-                    return edit.Beatmap.ToString();
+                    return edit.BeatmapInfo.ToString();
 
                 case UserActivity.InLobby lobby:
                     return privacyMode.Value == DiscordRichPresenceMode.Limited ? string.Empty : lobby.Room.Name.Value;

osu.Desktop/LegacyIpc/LegacyIpcDifficultyCalculationRequest.cs

@@ -0,0 +1,18 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+namespace osu.Desktop.LegacyIpc
+{
+    /// <summary>
+    /// A difficulty calculation request from the legacy client.
+    /// </summary>
+    /// <remarks>
+    /// Synchronise any changes with osu!stable.
+    /// </remarks>
+    public class LegacyIpcDifficultyCalculationRequest
+    {
+        public string BeatmapFile { get; set; }
+        public int RulesetId { get; set; }
+        public int Mods { get; set; }
+    }
+}

osu.Desktop/LegacyIpc/LegacyIpcDifficultyCalculationResponse.cs

@@ -0,0 +1,16 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+namespace osu.Desktop.LegacyIpc
+{
+    /// <summary>
+    /// A difficulty calculation response returned to the legacy client.
+    /// </summary>
+    /// <remarks>
+    /// Synchronise any changes with osu!stable.
+    /// </remarks>
+    public class LegacyIpcDifficultyCalculationResponse
+    {
+        public double StarRating { get; set; }
+    }
+}

osu.Desktop/LegacyIpc/LegacyIpcMessage.cs

@@ -0,0 +1,53 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Platform;
+using Newtonsoft.Json.Linq;
+
+namespace osu.Desktop.LegacyIpc
+{
+    /// <summary>
+    /// An <see cref="IpcMessage"/> that can be used to communicate to and from legacy clients.
+    /// <para>
+    /// In order to deserialise types at either end, types must be serialised as their <see cref="System.Type.AssemblyQualifiedName"/>,
+    /// however this cannot be done since osu!stable and osu!lazer live in two different assemblies.
+    /// <br />
+    /// To get around this, this class exists which serialises a payload (<see cref="LegacyIpcMessage.Data"/>) as an <see cref="System.Object"/> type,
+    /// which can be deserialised at either end because it is part of the core library (mscorlib / System.Private.CorLib).
+    /// The payload contains the data to be sent over the IPC channel.
+    /// <br />
+    /// At either end, Json.NET deserialises the payload into a <see cref="JObject"/> which is manually converted back into the expected <see cref="LegacyIpcMessage.Data"/> type,
+    /// which then further contains another <see cref="JObject"/> representing the data sent over the IPC channel whose type can likewise be lazily matched through
+    /// <see cref="LegacyIpcMessage.Data.MessageType"/>.
+    /// </para>
+    /// </summary>
+    /// <remarks>
+    /// Synchronise any changes with osu-stable.
+    /// </remarks>
+    public class LegacyIpcMessage : IpcMessage
+    {
+        public LegacyIpcMessage()
+        {
+            // Types/assemblies are not inter-compatible, so always serialise/deserialise into objects.
+            base.Type = typeof(object).FullName;
+        }
+
+        public new string Type => base.Type; // Hide setter.
+
+        public new object Value
+        {
+            get => base.Value;
+            set => base.Value = new Data
+            {
+                MessageType = value.GetType().Name,
+                MessageData = value
+            };
+        }
+
+        public class Data
+        {
+            public string MessageType { get; set; }
+            public object MessageData { get; set; }
+        }
+    }
+}

osu.Desktop/LegacyIpc/LegacyTcpIpcProvider.cs

@@ -0,0 +1,121 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Linq;
+using Newtonsoft.Json.Linq;
+using osu.Framework.Logging;
+using osu.Framework.Platform;
+using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.Legacy;
+using osu.Game.Rulesets;
+using osu.Game.Rulesets.Catch;
+using osu.Game.Rulesets.Mania;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu;
+using osu.Game.Rulesets.Taiko;
+
+#nullable enable
+
+namespace osu.Desktop.LegacyIpc
+{
+    /// <summary>
+    /// Provides IPC to legacy osu! clients.
+    /// </summary>
+    public class LegacyTcpIpcProvider : TcpIpcProvider
+    {
+        private static readonly Logger logger = Logger.GetLogger("legacy-ipc");
+
+        public LegacyTcpIpcProvider()
+            : base(45357)
+        {
+            MessageReceived += msg =>
+            {
+                try
+                {
+                    logger.Add("Processing legacy IPC message...");
+                    logger.Add($"    {msg.Value}", LogLevel.Debug);
+
+                    // See explanation in LegacyIpcMessage for why this is done this way.
+                    var legacyData = ((JObject)msg.Value).ToObject<LegacyIpcMessage.Data>();
+                    object value = parseObject((JObject)legacyData!.MessageData, legacyData.MessageType);
+
+                    return new LegacyIpcMessage
+                    {
+                        Value = onLegacyIpcMessageReceived(value)
+                    };
+                }
+                catch (Exception ex)
+                {
+                    logger.Add($"Processing IPC message failed: {msg.Value}", exception: ex);
+                    return null;
+                }
+            };
+        }
+
+        private object parseObject(JObject value, string type)
+        {
+            switch (type)
+            {
+                case nameof(LegacyIpcDifficultyCalculationRequest):
+                    return value.ToObject<LegacyIpcDifficultyCalculationRequest>()
+                           ?? throw new InvalidOperationException($"Failed to parse request {value}");
+
+                case nameof(LegacyIpcDifficultyCalculationResponse):
+                    return value.ToObject<LegacyIpcDifficultyCalculationResponse>()
+                           ?? throw new InvalidOperationException($"Failed to parse request {value}");
+
+                default:
+                    throw new ArgumentException($"Unsupported object type {type}");
+            }
+        }
+
+        private object onLegacyIpcMessageReceived(object message)
+        {
+            switch (message)
+            {
+                case LegacyIpcDifficultyCalculationRequest req:
+                    try
+                    {
+                        var ruleset = getLegacyRulesetFromID(req.RulesetId);
+
+                        Mod[] mods = ruleset.ConvertFromLegacyMods((LegacyMods)req.Mods).ToArray();
+                        WorkingBeatmap beatmap = new FlatFileWorkingBeatmap(req.BeatmapFile, _ => ruleset);
+
+                        return new LegacyIpcDifficultyCalculationResponse
+                        {
+                            StarRating = ruleset.CreateDifficultyCalculator(beatmap).Calculate(mods).StarRating
+                        };
+                    }
+                    catch
+                    {
+                        return new LegacyIpcDifficultyCalculationResponse();
+                    }
+
+                default:
+                    throw new ArgumentException($"Unsupported message type {message}");
+            }
+        }
+
+        private static Ruleset getLegacyRulesetFromID(int rulesetId)
+        {
+            switch (rulesetId)
+            {
+                case 0:
+                    return new OsuRuleset();
+
+                case 1:
+                    return new TaikoRuleset();
+
+                case 2:
+                    return new CatchRuleset();
+
+                case 3:
+                    return new ManiaRuleset();
+
+                default:
+                    throw new ArgumentException("Invalid ruleset id");
+            }
+        }
+    }
+}

osu.Desktop/OsuGameDesktop.cs

@@ -93,6 +93,11 @@ namespace osu.Desktop
 
         protected override UpdateManager CreateUpdateManager()
         {
+            string packageManaged = Environment.GetEnvironmentVariable("OSU_EXTERNAL_UPDATE_PROVIDER");
+
+            if (!string.IsNullOrEmpty(packageManaged))
+                return new NoActionUpdateManager();
+
             switch (RuntimeInfo.OS)
             {
                 case RuntimeInfo.Platform.Windows:
@@ -156,7 +161,7 @@ namespace osu.Desktop
         {
             lock (importableFiles)
             {
-                var firstExtension = Path.GetExtension(filePaths.First());
+                string firstExtension = Path.GetExtension(filePaths.First());
 
                 if (filePaths.Any(f => Path.GetExtension(f) != firstExtension)) return;
 
@@ -177,7 +182,7 @@ namespace osu.Desktop
             {
                 Logger.Log($"Handling batch import of {importableFiles.Count} files");
 
-                var paths = importableFiles.ToArray();
+                string[] paths = importableFiles.ToArray();
                 importableFiles.Clear();
 
                 Task.Factory.StartNew(() => Import(paths), TaskCreationOptions.LongRunning);

osu.Desktop/Program.cs

@@ -5,6 +5,7 @@ using System;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
+using osu.Desktop.LegacyIpc;
 using osu.Framework;
 using osu.Framework.Development;
 using osu.Framework.Logging;
@@ -18,21 +19,23 @@ namespace osu.Desktop
     {
         private const string base_game_name = @"osu";
 
+        private static LegacyTcpIpcProvider legacyIpc;
+
         [STAThread]
-        public static int Main(string[] args)
+        public static void Main(string[] args)
         {
             // Back up the cwd before DesktopGameHost changes it
-            var cwd = Environment.CurrentDirectory;
+            string cwd = Environment.CurrentDirectory;
 
             string gameName = base_game_name;
             bool tournamentClient = false;
 
-            foreach (var arg in args)
+            foreach (string arg in args)
             {
-                var split = arg.Split('=');
+                string[] split = arg.Split('=');
 
-                var key = split[0];
-                var val = split.Length > 1 ? split[1] : string.Empty;
+                string key = split[0];
+                string val = split.Length > 1 ? split[1] : string.Empty;
 
                 switch (key)
                 {
@@ -62,27 +65,43 @@ namespace osu.Desktop
                     {
                         var importer = new ArchiveImportIPCChannel(host);
 
-                        foreach (var file in args)
+                        foreach (string file in args)
                         {
                             Console.WriteLine(@"Importing {0}", file);
                             if (!importer.ImportAsync(Path.GetFullPath(file, cwd)).Wait(3000))
                                 throw new TimeoutException(@"IPC took too long to send");
                         }
 
-                        return 0;
+                        return;
                     }
 
                     // we want to allow multiple instances to be started when in debug.
                     if (!DebugUtils.IsDebugBuild)
-                        return 0;
+                    {
+                        Logger.Log(@"osu! does not support multiple running instances.", LoggingTarget.Runtime, LogLevel.Error);
+                        return;
+                    }
+                }
+
+                if (host.IsPrimaryInstance)
+                {
+                    try
+                    {
+                        Logger.Log("Starting legacy IPC provider...");
+                        legacyIpc = new LegacyTcpIpcProvider();
+                        legacyIpc.Bind();
+                        legacyIpc.StartAsync();
+                    }
+                    catch (Exception ex)
+                    {
+                        Logger.Error(ex, "Failed to start legacy IPC provider");
+                    }
                 }
 
                 if (tournamentClient)
                     host.Run(new TournamentGame());
                 else
                     host.Run(new OsuGameDesktop(args));
-
-                return 0;
             }
         }
 

osu.Desktop/Updater/SquirrelUpdateManager.cs

@@ -103,7 +103,10 @@ namespace osu.Desktop.Updater
                     }
                     else
                     {
+                        // In the case of an error, a separate notification will be displayed.
                         notification.State = ProgressNotificationState.Cancelled;
+                        notification.Close();
+
                         Logger.Error(e, @"update failed!");
                     }
                 }
@@ -183,6 +186,19 @@ namespace osu.Desktop.Updater
                     }
                 });
             }
+
+            public override void Close()
+            {
+                // cancelling updates is not currently supported by the underlying updater.
+                // only allow dismissing for now.
+
+                switch (State)
+                {
+                    case ProgressNotificationState.Cancelled:
+                        base.Close();
+                        break;
+                }
+            }
         }
 
         private class SquirrelLogger : Splat.ILogger, IDisposable

osu.Game.Benchmarks/osu.Game.Benchmarks.csproj

@@ -9,7 +9,7 @@
   <ItemGroup>
     <PackageReference Include="BenchmarkDotNet" Version="0.13.1" />
     <PackageReference Include="nunit" Version="3.13.2" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.1.0" />
   </ItemGroup>
 
   <ItemGroup>

osu.Game.Rulesets.Catch.Tests.iOS/Application.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.iOS;
 using UIKit;
 
 namespace osu.Game.Rulesets.Catch.Tests.iOS
@@ -9,7 +10,7 @@ namespace osu.Game.Rulesets.Catch.Tests.iOS
     {
         public static void Main(string[] args)
         {
-            UIApplication.Main(args, "GameUIApplication", "AppDelegate");
+            UIApplication.Main(args, typeof(GameUIApplication), typeof(AppDelegate));
         }
     }
 }

osu.Game.Rulesets.Catch.Tests/CatchDifficultyCalculatorTest.cs

@@ -14,15 +14,15 @@ namespace osu.Game.Rulesets.Catch.Tests
     {
         protected override string ResourceAssembly => "osu.Game.Rulesets.Catch";
 
-        [TestCase(4.050601681491468d, "diffcalc-test")]
+        [TestCase(4.0505463516206195d, "diffcalc-test")]
         public void Test(double expected, string name)
             => base.Test(expected, name);
 
-        [TestCase(5.169743871843191d, "diffcalc-test")]
+        [TestCase(5.1696411260785498d, "diffcalc-test")]
         public void TestClockRateAdjusted(double expected, string name)
             => Test(expected, name, new CatchModDoubleTime());
 
-        protected override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new CatchDifficultyCalculator(new CatchRuleset(), beatmap);
+        protected override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new CatchDifficultyCalculator(new CatchRuleset().RulesetInfo, beatmap);
 
         protected override Ruleset CreateRuleset() => new CatchRuleset();
     }

osu.Game.Rulesets.Catch.Tests/Editor/CatchSelectionBlueprintTestScene.cs

@@ -29,8 +29,7 @@ namespace osu.Game.Rulesets.Catch.Tests.Editor
 
         protected CatchSelectionBlueprintTestScene()
         {
-            EditorBeatmap = new EditorBeatmap(new CatchBeatmap());
-            EditorBeatmap.BeatmapInfo.BaseDifficulty.CircleSize = 0;
+            EditorBeatmap = new EditorBeatmap(new CatchBeatmap()) { Difficulty = { CircleSize = 0 } };
             EditorBeatmap.ControlPointInfo.Add(0, new TimingControlPoint
             {
                 BeatLength = 100

osu.Game.Rulesets.Catch.Tests/Editor/Checks/TestCheckBananaShowerGap.cs

@@ -0,0 +1,118 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+using System.Linq;
+using NUnit.Framework;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Catch.Edit.Checks;
+using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Tests.Beatmaps;
+
+namespace osu.Game.Rulesets.Catch.Tests.Editor.Checks
+{
+    [TestFixture]
+    public class TestCheckBananaShowerGap
+    {
+        private CheckBananaShowerGap check;
+
+        [SetUp]
+        public void Setup()
+        {
+            check = new CheckBananaShowerGap();
+        }
+
+        [Test]
+        public void TestAllowedSpinnerGaps()
+        {
+            assertOk(mockBeatmap(250, 1000, 1250), DifficultyRating.Easy);
+            assertOk(mockBeatmap(250, 1000, 1250), DifficultyRating.Normal);
+            assertOk(mockBeatmap(125, 1000, 1250), DifficultyRating.Hard);
+            assertOk(mockBeatmap(125, 1000, 1125), DifficultyRating.Insane);
+            assertOk(mockBeatmap(62, 1000, 1125), DifficultyRating.Expert);
+            assertOk(mockBeatmap(62, 1000, 1125), DifficultyRating.ExpertPlus);
+        }
+
+        [Test]
+        public void TestDisallowedSpinnerGapStart()
+        {
+            assertTooShortSpinnerStart(mockBeatmap(249, 1000, 1250), DifficultyRating.Easy);
+            assertTooShortSpinnerStart(mockBeatmap(249, 1000, 1250), DifficultyRating.Normal);
+            assertTooShortSpinnerStart(mockBeatmap(124, 1000, 1250), DifficultyRating.Hard);
+            assertTooShortSpinnerStart(mockBeatmap(124, 1000, 1250), DifficultyRating.Insane);
+            assertTooShortSpinnerStart(mockBeatmap(61, 1000, 1250), DifficultyRating.Expert);
+            assertTooShortSpinnerStart(mockBeatmap(61, 1000, 1250), DifficultyRating.ExpertPlus);
+        }
+
+        [Test]
+        public void TestDisallowedSpinnerGapEnd()
+        {
+            assertTooShortSpinnerEnd(mockBeatmap(250, 1000, 1249), DifficultyRating.Easy);
+            assertTooShortSpinnerEnd(mockBeatmap(250, 1000, 1249), DifficultyRating.Normal);
+            assertTooShortSpinnerEnd(mockBeatmap(125, 1000, 1249), DifficultyRating.Hard);
+            assertTooShortSpinnerEnd(mockBeatmap(125, 1000, 1124), DifficultyRating.Insane);
+            assertTooShortSpinnerEnd(mockBeatmap(62, 1000, 1124), DifficultyRating.Expert);
+            assertTooShortSpinnerEnd(mockBeatmap(62, 1000, 1124), DifficultyRating.ExpertPlus);
+        }
+
+        [Test]
+        public void TestConsecutiveSpinners()
+        {
+            var spinnerConsecutiveBeatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new BananaShower { StartTime = 0, EndTime = 100, X = 0 },
+                    new BananaShower { StartTime = 101, EndTime = 200, X = 0 },
+                    new BananaShower { StartTime = 201, EndTime = 300, X = 0 }
+                }
+            };
+
+            assertOk(spinnerConsecutiveBeatmap, DifficultyRating.Easy);
+            assertOk(spinnerConsecutiveBeatmap, DifficultyRating.Normal);
+            assertOk(spinnerConsecutiveBeatmap, DifficultyRating.Hard);
+            assertOk(spinnerConsecutiveBeatmap, DifficultyRating.Insane);
+            assertOk(spinnerConsecutiveBeatmap, DifficultyRating.Expert);
+            assertOk(spinnerConsecutiveBeatmap, DifficultyRating.ExpertPlus);
+        }
+
+        private Beatmap<HitObject> mockBeatmap(double bananaShowerStart, double bananaShowerEnd, double nextFruitStart)
+        {
+            return new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new Fruit { StartTime = 0, X = 0 },
+                    new BananaShower { StartTime = bananaShowerStart, EndTime = bananaShowerEnd, X = 0 },
+                    new Fruit { StartTime = nextFruitStart, X = 0 }
+                }
+            };
+        }
+
+        private void assertOk(IBeatmap beatmap, DifficultyRating difficultyRating)
+        {
+            var context = new BeatmapVerifierContext(beatmap, new TestWorkingBeatmap(beatmap), difficultyRating);
+            Assert.That(check.Run(context), Is.Empty);
+        }
+
+        private void assertTooShortSpinnerStart(IBeatmap beatmap, DifficultyRating difficultyRating)
+        {
+            var context = new BeatmapVerifierContext(beatmap, new TestWorkingBeatmap(beatmap), difficultyRating);
+            var issues = check.Run(context).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(1));
+            Assert.That(issues.All(issue => issue.Template is CheckBananaShowerGap.IssueTemplateBananaShowerStartGap));
+        }
+
+        private void assertTooShortSpinnerEnd(IBeatmap beatmap, DifficultyRating difficultyRating)
+        {
+            var context = new BeatmapVerifierContext(beatmap, new TestWorkingBeatmap(beatmap), difficultyRating);
+            var issues = check.Run(context).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(1));
+            Assert.That(issues.All(issue => issue.Template is CheckBananaShowerGap.IssueTemplateBananaShowerEndGap));
+        }
+    }
+}

osu.Game.Rulesets.Catch.Tests/Editor/TestSceneBananaShowerPlacementBlueprint.cs

@@ -5,6 +5,7 @@ using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Testing;
 using osu.Framework.Utils;
+using osu.Game.Beatmaps;
 using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Rulesets.Catch.Edit.Blueprints;
 using osu.Game.Rulesets.Catch.Edit.Blueprints.Components;
@@ -26,7 +27,7 @@ namespace osu.Game.Rulesets.Catch.Tests.Editor
         protected override void AddHitObject(DrawableHitObject hitObject)
         {
             // Create nested bananas (but positions are not randomized because beatmap processing is not done).
-            hitObject.HitObject.ApplyDefaults(new ControlPointInfo(), Beatmap.Value.BeatmapInfo.BaseDifficulty);
+            hitObject.HitObject.ApplyDefaults(new ControlPointInfo(), new BeatmapDifficulty());
 
             base.AddHitObject(hitObject);
         }

osu.Game.Rulesets.Catch.Tests/Editor/TestSceneCatchDistanceSnapGrid.cs

@@ -0,0 +1,91 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Input.Events;
+using osu.Framework.Timing;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Catch.Edit;
+using osu.Game.Rulesets.Catch.Edit.Blueprints.Components;
+using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Catch.UI;
+using osu.Game.Rulesets.UI;
+using osu.Game.Rulesets.UI.Scrolling;
+using osu.Game.Tests.Visual;
+using osuTK;
+
+namespace osu.Game.Rulesets.Catch.Tests.Editor
+{
+    public class TestSceneCatchDistanceSnapGrid : OsuManualInputManagerTestScene
+    {
+        private readonly ManualClock manualClock = new ManualClock();
+
+        [Cached(typeof(Playfield))]
+        private readonly CatchPlayfield playfield;
+
+        private ScrollingHitObjectContainer hitObjectContainer => playfield.HitObjectContainer;
+
+        private readonly CatchDistanceSnapGrid distanceGrid;
+
+        private readonly FruitOutline fruitOutline;
+
+        private readonly Fruit fruit = new Fruit();
+
+        public TestSceneCatchDistanceSnapGrid()
+        {
+            Child = new Container
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                RelativeSizeAxes = Axes.Y,
+                Width = 500,
+
+                Children = new Drawable[]
+                {
+                    new ScrollingTestContainer(ScrollingDirection.Down)
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        Child = playfield = new CatchPlayfield(new BeatmapDifficulty())
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                            Clock = new FramedClock(manualClock)
+                        }
+                    },
+                    distanceGrid = new CatchDistanceSnapGrid(new double[] { 0, -1, 1 }),
+                    fruitOutline = new FruitOutline()
+                },
+            };
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            distanceGrid.StartTime = 100;
+            distanceGrid.StartX = 250;
+
+            Vector2 screenSpacePosition = InputManager.CurrentState.Mouse.Position;
+
+            var result = distanceGrid.GetSnappedPosition(screenSpacePosition);
+
+            if (result != null)
+            {
+                fruit.OriginalX = hitObjectContainer.ToLocalSpace(result.ScreenSpacePosition).X;
+
+                if (result.Time != null)
+                    fruit.StartTime = result.Time.Value;
+            }
+
+            fruitOutline.Position = CatchHitObjectUtils.GetStartPosition(hitObjectContainer, fruit);
+            fruitOutline.UpdateFrom(fruit);
+        }
+
+        protected override bool OnScroll(ScrollEvent e)
+        {
+            manualClock.CurrentTime -= e.ScrollDelta.Y * 50;
+            return true;
+        }
+    }
+}

osu.Game.Rulesets.Catch.Tests/Editor/TestSceneJuiceStreamPlacementBlueprint.cs

@@ -4,9 +4,9 @@
 using System.Collections.Generic;
 using System.Linq;
 using NUnit.Framework;
-using osu.Framework.Allocation;
 using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Utils;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Catch.Edit.Blueprints;
 using osu.Game.Rulesets.Catch.Objects;
 using osu.Game.Rulesets.Catch.Objects.Drawables;
@@ -23,11 +23,12 @@ namespace osu.Game.Rulesets.Catch.Tests.Editor
 
         private JuiceStream lastObject => LastObject?.HitObject as JuiceStream;
 
-        [BackgroundDependencyLoader]
-        private void load()
+        protected override IBeatmap GetPlayableBeatmap()
         {
-            Beatmap.Value.BeatmapInfo.BaseDifficulty.SliderTickRate = 5;
-            Beatmap.Value.BeatmapInfo.BaseDifficulty.SliderMultiplier = velocity * 10;
+            var playable = base.GetPlayableBeatmap();
+            playable.Difficulty.SliderTickRate = 5;
+            playable.Difficulty.SliderMultiplier = velocity * 10;
+            return playable;
         }
 
         [Test]

osu.Game.Rulesets.Catch.Tests/Editor/TestSceneJuiceStreamSelectionBlueprint.cs

@@ -49,7 +49,7 @@ namespace osu.Game.Rulesets.Catch.Tests.Editor
 
             AddAssert("correct outline count", () =>
             {
-                var expected = hitObject.NestedHitObjects.Count(h => !(h is TinyDroplet));
+                int expected = hitObject.NestedHitObjects.Count(h => !(h is TinyDroplet));
                 return this.ChildrenOfType<FruitOutline>().Count() == expected;
             });
             AddAssert("correct vertex piece count", () =>
@@ -223,7 +223,7 @@ namespace osu.Game.Rulesets.Catch.Tests.Editor
                 X = x,
                 Path = sliderPath,
             };
-            EditorBeatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier = velocity;
+            EditorBeatmap.Difficulty.SliderMultiplier = velocity;
             EditorBeatmap.Add(hitObject);
             EditorBeatmap.Update(hitObject);
             Assert.That(hitObject.Velocity, Is.EqualTo(velocity));

osu.Game.Rulesets.Catch.Tests/Mods/TestSceneCatchModNoScope.cs

@@ -0,0 +1,110 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+using NUnit.Framework;
+using osu.Framework.Utils;
+using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.Timing;
+using osu.Game.Rulesets.Catch.Mods;
+using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Catch.UI;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Tests.Visual;
+
+namespace osu.Game.Rulesets.Catch.Tests.Mods
+{
+    public class TestSceneCatchModNoScope : ModTestScene
+    {
+        protected override Ruleset CreatePlayerRuleset() => new CatchRuleset();
+
+        [Test]
+        public void TestVisibleDuringBreak()
+        {
+            CreateModTest(new ModTestData
+            {
+                Mod = new CatchModNoScope
+                {
+                    HiddenComboCount = { Value = 0 },
+                },
+                Autoplay = true,
+                PassCondition = () => true,
+                Beatmap = new Beatmap
+                {
+                    HitObjects = new List<HitObject>
+                    {
+                        new Fruit
+                        {
+                            X = CatchPlayfield.CENTER_X,
+                            StartTime = 1000,
+                        },
+                        new Fruit
+                        {
+                            X = CatchPlayfield.CENTER_X,
+                            StartTime = 5000,
+                        }
+                    },
+                    Breaks = new List<BreakPeriod>
+                    {
+                        new BreakPeriod(2000, 4000),
+                    }
+                }
+            });
+
+            AddUntilStep("wait for catcher to hide", () => catcherAlphaAlmostEquals(0));
+            AddUntilStep("wait for start of break", isBreak);
+            AddUntilStep("wait for catcher to show", () => catcherAlphaAlmostEquals(1));
+            AddUntilStep("wait for end of break", () => !isBreak());
+            AddUntilStep("wait for catcher to hide", () => catcherAlphaAlmostEquals(0));
+        }
+
+        [Test]
+        public void TestVisibleAfterComboBreak()
+        {
+            CreateModTest(new ModTestData
+            {
+                Mod = new CatchModNoScope
+                {
+                    HiddenComboCount = { Value = 2 },
+                },
+                Autoplay = true,
+                PassCondition = () => true,
+                Beatmap = new Beatmap
+                {
+                    HitObjects = new List<HitObject>
+                    {
+                        new Fruit
+                        {
+                            X = 0,
+                            StartTime = 1000,
+                        },
+                        new Fruit
+                        {
+                            X = CatchPlayfield.CENTER_X,
+                            StartTime = 3000,
+                        },
+                        new Fruit
+                        {
+                            X = CatchPlayfield.WIDTH,
+                            StartTime = 5000,
+                        },
+                    }
+                }
+            });
+
+            AddAssert("catcher must start visible", () => catcherAlphaAlmostEquals(1));
+            AddUntilStep("wait for combo", () => Player.ScoreProcessor.Combo.Value >= 2);
+            AddAssert("catcher must dim after combo", () => !catcherAlphaAlmostEquals(1));
+            AddStep("break combo", () => Player.ScoreProcessor.Combo.Value = 0);
+            AddUntilStep("wait for catcher to show", () => catcherAlphaAlmostEquals(1));
+        }
+
+        private bool isBreak() => Player.IsBreakTime.Value;
+
+        private bool catcherAlphaAlmostEquals(float alpha)
+        {
+            var playfield = (CatchPlayfield)Player.DrawableRuleset.Playfield;
+            return Precision.AlmostEquals(playfield.CatcherArea.Alpha, alpha);
+        }
+    }
+}

osu.Game.Rulesets.Catch.Tests/TestSceneCatcher.cs

@@ -103,7 +103,7 @@ namespace osu.Game.Rulesets.Catch.Tests
         [Test]
         public void TestCatcherCatchWidth()
         {
-            var halfWidth = Catcher.CalculateCatchWidth(new BeatmapDifficulty { CircleSize = 0 }) / 2;
+            float halfWidth = Catcher.CalculateCatchWidth(new BeatmapDifficulty { CircleSize = 0 }) / 2;
             AddStep("catch fruit", () =>
             {
                 attemptCatch(new Fruit { X = -halfWidth + 1 });
@@ -168,6 +168,28 @@ namespace osu.Game.Rulesets.Catch.Tests
             checkHyperDash(false);
         }
 
+        [Test]
+        public void TestLastBananaShouldClearPlateOnMiss()
+        {
+            AddStep("catch fruit", () => attemptCatch(new Fruit()));
+            checkPlate(1);
+            AddStep("miss banana", () => attemptCatch(new Banana { X = 100 }));
+            checkPlate(1);
+            AddStep("miss last banana", () => attemptCatch(new Banana { LastInCombo = true, X = 100 }));
+            checkPlate(0);
+        }
+
+        [Test]
+        public void TestLastBananaShouldClearPlateOnCatch()
+        {
+            AddStep("catch fruit", () => attemptCatch(new Fruit()));
+            checkPlate(1);
+            AddStep("catch banana", () => attemptCatch(new Banana()));
+            checkPlate(2);
+            AddStep("catch last banana", () => attemptCatch(new Banana { LastInCombo = true }));
+            checkPlate(0);
+        }
+
         [Test]
         public void TestCatcherRandomStacking()
         {
@@ -237,7 +259,7 @@ namespace osu.Game.Rulesets.Catch.Tests
 
         private void attemptCatch(Func<CatchHitObject> hitObject, int count)
         {
-            for (var i = 0; i < count; i++)
+            for (int i = 0; i < count; i++)
                 attemptCatch(hitObject(), out _, out _);
         }
 
@@ -290,7 +312,7 @@ namespace osu.Game.Rulesets.Catch.Tests
         {
             public IEnumerable<CaughtObject> CaughtObjects => this.ChildrenOfType<CaughtObject>();
 
-            public TestCatcher(DroppedObjectContainer droppedObjectTarget, BeatmapDifficulty difficulty)
+            public TestCatcher(DroppedObjectContainer droppedObjectTarget, IBeatmapDifficultyInfo difficulty)
                 : base(droppedObjectTarget, difficulty)
             {
             }
@@ -298,7 +320,7 @@ namespace osu.Game.Rulesets.Catch.Tests
 
         public class TestKiaiFruit : Fruit
         {
-            protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+            protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, IBeatmapDifficultyInfo difficulty)
             {
                 controlPointInfo.Add(0, new EffectControlPoint { KiaiMode = true });
                 base.ApplyDefaultsToSelf(controlPointInfo, difficulty);

osu.Game.Rulesets.Catch.Tests/TestSceneCatcherArea.cs

@@ -34,7 +34,7 @@ namespace osu.Game.Rulesets.Catch.Tests
 
         private ScheduledDelegate addManyFruit;
 
-        private BeatmapDifficulty beatmapDifficulty;
+        private IBeatmapDifficultyInfo beatmapDifficulty;
 
         public TestSceneCatcherArea()
         {
@@ -120,7 +120,7 @@ namespace osu.Game.Rulesets.Catch.Tests
 
         private class TestCatcherArea : CatcherArea
         {
-            public TestCatcherArea(BeatmapDifficulty beatmapDifficulty)
+            public TestCatcherArea(IBeatmapDifficultyInfo beatmapDifficulty)
             {
                 var droppedObjectContainer = new DroppedObjectContainer();
                 Add(droppedObjectContainer);

osu.Game.Rulesets.Catch.Tests/TestSceneDrawableHitObjects.cs

@@ -30,7 +30,7 @@ namespace osu.Game.Rulesets.Catch.Tests
             var controlPointInfo = new ControlPointInfo();
             controlPointInfo.Add(0, new TimingControlPoint());
 
-            WorkingBeatmap beatmap = CreateWorkingBeatmap(new Beatmap
+            IWorkingBeatmap beatmap = CreateWorkingBeatmap(new Beatmap
             {
                 HitObjects = new List<HitObject> { new Fruit() },
                 BeatmapInfo = new BeatmapInfo
@@ -118,7 +118,7 @@ namespace osu.Game.Rulesets.Catch.Tests
 
         private void spawnJuiceStream(bool hit = false)
         {
-            var xCoords = getXCoords(hit);
+            float xCoords = getXCoords(hit);
 
             var juice = new JuiceStream
             {

osu.Game.Rulesets.Catch.Tests/osu.Game.Rulesets.Catch.Tests.csproj

@@ -2,9 +2,9 @@
   <Import Project="..\osu.TestProject.props" />
   <ItemGroup Label="Package References">
     <PackageReference Include="Appveyor.TestLogger" Version="2.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
     <PackageReference Include="NUnit" Version="3.13.2" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.1.0" />
     <PackageReference Update="Microsoft.EntityFrameworkCore.Sqlite" Version="2.1.4" />
   </ItemGroup>
   <PropertyGroup Label="Project">

osu.Game.Rulesets.Catch/Beatmaps/CatchBeatmapProcessor.cs

@@ -211,7 +211,7 @@ namespace osu.Game.Rulesets.Catch.Beatmaps
 
             palpableObjects.Sort((h1, h2) => h1.StartTime.CompareTo(h2.StartTime));
 
-            double halfCatcherWidth = Catcher.CalculateCatchWidth(beatmap.BeatmapInfo.BaseDifficulty) / 2;
+            double halfCatcherWidth = Catcher.CalculateCatchWidth(beatmap.Difficulty) / 2;
 
             // Todo: This is wrong. osu!stable calculated hyperdashes using the full catcher size, excluding the margins.
             // This should theoretically cause impossible scenarios, but practically, likely due to the size of the playfield, it doesn't seem possible.
@@ -233,7 +233,7 @@ namespace osu.Game.Rulesets.Catch.Beatmaps
                 int thisDirection = nextObject.EffectiveX > currentObject.EffectiveX ? 1 : -1;
                 double timeToNext = nextObject.StartTime - currentObject.StartTime - 1000f / 60f / 4; // 1/4th of a frame of grace time, taken from osu-stable
                 double distanceToNext = Math.Abs(nextObject.EffectiveX - currentObject.EffectiveX) - (lastDirection == thisDirection ? lastExcess : halfCatcherWidth);
-                float distanceToHyper = (float)(timeToNext * Catcher.BASE_SPEED - distanceToNext);
+                float distanceToHyper = (float)(timeToNext * Catcher.BASE_DASH_SPEED - distanceToNext);
 
                 if (distanceToHyper < 0)
                 {

osu.Game.Rulesets.Catch/CatchRuleset.cs

@@ -133,6 +133,7 @@ namespace osu.Game.Rulesets.Catch
                         new MultiMod(new ModWindUp(), new ModWindDown()),
                         new CatchModFloatingFruits(),
                         new CatchModMuted(),
+                        new CatchModNoScope(),
                     };
 
                 default:
@@ -177,7 +178,7 @@ namespace osu.Game.Rulesets.Catch
             return base.GetDisplayNameForHitResult(result);
         }
 
-        public override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new CatchDifficultyCalculator(this, beatmap);
+        public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new CatchDifficultyCalculator(RulesetInfo, beatmap);
 
         public override ISkin CreateLegacySkinProvider(ISkin skin, IBeatmap beatmap) => new CatchLegacySkinTransformer(skin);
 
@@ -188,5 +189,7 @@ namespace osu.Game.Rulesets.Catch
         public override IConvertibleReplayFrame CreateConvertibleReplayFrame() => new CatchReplayFrame();
 
         public override HitObjectComposer CreateHitObjectComposer() => new CatchHitObjectComposer(this);
+
+        public override IBeatmapVerifier CreateBeatmapVerifier() => new CatchBeatmapVerifier();
     }
 }

osu.Game.Rulesets.Catch/Difficulty/CatchDifficultyAttributes.cs

@@ -1,12 +1,35 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.Collections.Generic;
+using Newtonsoft.Json;
 using osu.Game.Rulesets.Difficulty;
 
 namespace osu.Game.Rulesets.Catch.Difficulty
 {
     public class CatchDifficultyAttributes : DifficultyAttributes
     {
+        [JsonProperty("approach_rate")]
         public double ApproachRate { get; set; }
+
+        public override IEnumerable<(int attributeId, object value)> ToDatabaseAttributes()
+        {
+            foreach (var v in base.ToDatabaseAttributes())
+                yield return v;
+
+            // Todo: osu!catch should not output star rating in the 'aim' attribute.
+            yield return (ATTRIB_ID_AIM, StarRating);
+            yield return (ATTRIB_ID_APPROACH_RATE, ApproachRate);
+            yield return (ATTRIB_ID_MAX_COMBO, MaxCombo);
+        }
+
+        public override void FromDatabaseAttributes(IReadOnlyDictionary<int, double> values)
+        {
+            base.FromDatabaseAttributes(values);
+
+            StarRating = values[ATTRIB_ID_AIM];
+            ApproachRate = values[ATTRIB_ID_APPROACH_RATE];
+            MaxCombo = (int)values[ATTRIB_ID_MAX_COMBO];
+        }
     }
 }

osu.Game.Rulesets.Catch/Difficulty/CatchDifficultyCalculator.cs

@@ -23,7 +23,7 @@ namespace osu.Game.Rulesets.Catch.Difficulty
 
         private float halfCatcherWidth;
 
-        public CatchDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
+        public CatchDifficultyCalculator(IRulesetInfo ruleset, IWorkingBeatmap beatmap)
             : base(ruleset, beatmap)
         {
         }
@@ -31,10 +31,10 @@ namespace osu.Game.Rulesets.Catch.Difficulty
         protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
         {
             if (beatmap.HitObjects.Count == 0)
-                return new CatchDifficultyAttributes { Mods = mods, Skills = skills };
+                return new CatchDifficultyAttributes { Mods = mods };
 
             // this is the same as osu!, so there's potential to share the implementation... maybe
-            double preempt = BeatmapDifficulty.DifficultyRange(beatmap.BeatmapInfo.BaseDifficulty.ApproachRate, 1800, 1200, 450) / clockRate;
+            double preempt = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.ApproachRate, 1800, 1200, 450) / clockRate;
 
             return new CatchDifficultyAttributes
             {
@@ -42,7 +42,6 @@ namespace osu.Game.Rulesets.Catch.Difficulty
                 Mods = mods,
                 ApproachRate = preempt > 1200.0 ? -(preempt - 1800.0) / 120.0 : -(preempt - 1200.0) / 150.0 + 5.0,
                 MaxCombo = beatmap.HitObjects.Count(h => h is Fruit) + beatmap.HitObjects.OfType<JuiceStream>().SelectMany(j => j.NestedHitObjects).Count(h => !(h is TinyDroplet)),
-                Skills = skills
             };
         }
 
@@ -52,7 +51,7 @@ namespace osu.Game.Rulesets.Catch.Difficulty
 
             // In 2B beatmaps, it is possible that a normal Fruit is placed in the middle of a JuiceStream.
             foreach (var hitObject in beatmap.HitObjects
-                                             .SelectMany(obj => obj is JuiceStream stream ? stream.NestedHitObjects : new[] { obj })
+                                             .SelectMany(obj => obj is JuiceStream stream ? stream.NestedHitObjects.AsEnumerable() : new[] { obj })
                                              .Cast<CatchHitObject>()
                                              .OrderBy(x => x.StartTime))
             {
@@ -69,10 +68,10 @@ namespace osu.Game.Rulesets.Catch.Difficulty
 
         protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate)
         {
-            halfCatcherWidth = Catcher.CalculateCatchWidth(beatmap.BeatmapInfo.BaseDifficulty) * 0.5f;
+            halfCatcherWidth = Catcher.CalculateCatchWidth(beatmap.Difficulty) * 0.5f;
 
             // For circle sizes above 5.5, reduce the catcher width further to simulate imperfect gameplay.
-            halfCatcherWidth *= 1 - (Math.Max(0, beatmap.BeatmapInfo.BaseDifficulty.CircleSize - 5.5f) * 0.0625f);
+            halfCatcherWidth *= 1 - (Math.Max(0, beatmap.Difficulty.CircleSize - 5.5f) * 0.0625f);
 
             return new Skill[]
             {

osu.Game.Rulesets.Catch/Difficulty/Preprocessing/CatchDifficultyHitObject.cs

@@ -28,7 +28,7 @@ namespace osu.Game.Rulesets.Catch.Difficulty.Preprocessing
             : base(hitObject, lastObject, clockRate)
         {
             // We will scale everything by this factor, so we can assume a uniform CircleSize among beatmaps.
-            var scalingFactor = normalized_hitobject_radius / halfCatcherWidth;
+            float scalingFactor = normalized_hitobject_radius / halfCatcherWidth;
 
             NormalizedPosition = BaseObject.EffectiveX * scalingFactor;
             LastNormalizedPosition = LastObject.EffectiveX * scalingFactor;

osu.Game.Rulesets.Catch/Edit/CatchBeatmapVerifier.cs

@@ -0,0 +1,24 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+using System.Linq;
+using osu.Game.Rulesets.Catch.Edit.Checks;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Edit.Checks.Components;
+
+namespace osu.Game.Rulesets.Catch.Edit
+{
+    public class CatchBeatmapVerifier : IBeatmapVerifier
+    {
+        private readonly List<ICheck> checks = new List<ICheck>
+        {
+            new CheckBananaShowerGap()
+        };
+
+        public IEnumerable<Issue> Run(BeatmapVerifierContext context)
+        {
+            return checks.SelectMany(check => check.Run(context));
+        }
+    }
+}

osu.Game.Rulesets.Catch/Edit/CatchDistanceSnapGrid.cs

@@ -0,0 +1,141 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using JetBrains.Annotations;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Lines;
+using osu.Framework.Graphics.Primitives;
+using osu.Game.Rulesets.Catch.UI;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.UI;
+using osu.Game.Rulesets.UI.Scrolling;
+using osuTK;
+
+namespace osu.Game.Rulesets.Catch.Edit
+{
+    /// <summary>
+    /// The guide lines used in the osu!catch editor to compose patterns that can be caught with constant speed.
+    /// Currently, only forward placement (an object is snapped based on the previous object, not the opposite) is supported.
+    /// </summary>
+    public class CatchDistanceSnapGrid : CompositeDrawable
+    {
+        public double StartTime { get; set; }
+
+        public float StartX { get; set; }
+
+        private const double max_vertical_line_length_in_time = CatchPlayfield.WIDTH / Catcher.BASE_WALK_SPEED;
+
+        private readonly double[] velocities;
+
+        private readonly List<Path> verticalPaths = new List<Path>();
+
+        private readonly List<Vector2[]> verticalLineVertices = new List<Vector2[]>();
+
+        [Resolved]
+        private Playfield playfield { get; set; }
+
+        private ScrollingHitObjectContainer hitObjectContainer => (ScrollingHitObjectContainer)playfield.HitObjectContainer;
+
+        public CatchDistanceSnapGrid(double[] velocities)
+        {
+            RelativeSizeAxes = Axes.Both;
+            Anchor = Anchor.BottomLeft;
+
+            this.velocities = velocities;
+
+            for (int i = 0; i < velocities.Length; i++)
+            {
+                verticalPaths.Add(new SmoothPath
+                {
+                    PathRadius = 2,
+                    Alpha = 0.5f,
+                });
+
+                verticalLineVertices.Add(new[] { Vector2.Zero, Vector2.Zero });
+            }
+
+            AddRangeInternal(verticalPaths);
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            double currentTime = hitObjectContainer.Time.Current;
+
+            for (int i = 0; i < velocities.Length; i++)
+            {
+                double velocity = velocities[i];
+
+                // The line ends at the top of the playfield.
+                double endTime = hitObjectContainer.TimeAtPosition(-hitObjectContainer.DrawHeight, currentTime);
+
+                // Non-vertical lines are cut at the sides of the playfield.
+                // Vertical lines are cut at some reasonable length.
+                if (velocity > 0)
+                    endTime = Math.Min(endTime, StartTime + (CatchPlayfield.WIDTH - StartX) / velocity);
+                else if (velocity < 0)
+                    endTime = Math.Min(endTime, StartTime + StartX / -velocity);
+                else
+                    endTime = Math.Min(endTime, StartTime + max_vertical_line_length_in_time);
+
+                Vector2[] lineVertices = verticalLineVertices[i];
+                lineVertices[0] = calculatePosition(velocity, StartTime);
+                lineVertices[1] = calculatePosition(velocity, endTime);
+
+                var verticalPath = verticalPaths[i];
+                verticalPath.Vertices = verticalLineVertices[i];
+                verticalPath.OriginPosition = verticalPath.PositionInBoundingBox(Vector2.Zero);
+            }
+
+            Vector2 calculatePosition(double velocity, double time)
+            {
+                // Don't draw inverted lines.
+                time = Math.Max(time, StartTime);
+
+                float x = StartX + (float)((time - StartTime) * velocity);
+                float y = hitObjectContainer.PositionAtTime(time, currentTime);
+                return new Vector2(x, y);
+            }
+        }
+
+        [CanBeNull]
+        public SnapResult GetSnappedPosition(Vector2 screenSpacePosition)
+        {
+            double time = hitObjectContainer.TimeAtScreenSpacePosition(screenSpacePosition);
+
+            // If the cursor is below the distance snap grid, snap to the origin.
+            // Not returning `null` to retain the continuous snapping behavior when the cursor is slightly below the origin.
+            // This behavior is not currently visible in the editor because editor chooses the snap start time based on the mouse position.
+            if (time <= StartTime)
+            {
+                float y = hitObjectContainer.PositionAtTime(StartTime);
+                Vector2 originPosition = hitObjectContainer.ToScreenSpace(new Vector2(StartX, y));
+                return new SnapResult(originPosition, StartTime);
+            }
+
+            return enumerateSnappingCandidates(time)
+                   .OrderBy(pos => Vector2.DistanceSquared(screenSpacePosition, pos.ScreenSpacePosition))
+                   .FirstOrDefault();
+        }
+
+        private IEnumerable<SnapResult> enumerateSnappingCandidates(double time)
+        {
+            float y = hitObjectContainer.PositionAtTime(time);
+
+            foreach (double velocity in velocities)
+            {
+                float x = (float)(StartX + (time - StartTime) * velocity);
+                Vector2 screenSpacePosition = hitObjectContainer.ToScreenSpace(new Vector2(x, y + hitObjectContainer.DrawHeight));
+                yield return new SnapResult(screenSpacePosition, time);
+            }
+        }
+
+        protected override bool ComputeIsMaskedAway(RectangleF maskingBounds) => false;
+    }
+}

osu.Game.Rulesets.Catch/Edit/CatchEditorPlayfield.cs

@@ -9,7 +9,7 @@ namespace osu.Game.Rulesets.Catch.Edit
     public class CatchEditorPlayfield : CatchPlayfield
     {
         // TODO fixme: the size of the catcher is not changed when circle size is changed in setup screen.
-        public CatchEditorPlayfield(BeatmapDifficulty difficulty)
+        public CatchEditorPlayfield(IBeatmapDifficultyInfo difficulty)
             : base(difficulty)
         {
         }

osu.Game.Rulesets.Catch/Edit/CatchHitObjectComposer.cs

@@ -2,14 +2,23 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
+using System.Linq;
+using JetBrains.Annotations;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Input;
 using osu.Game.Beatmaps;
+using osu.Game.Graphics.UserInterface;
 using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Catch.UI;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.UI;
+using osu.Game.Screens.Edit.Components.TernaryButtons;
 using osu.Game.Screens.Edit.Compose.Components;
 using osuTK;
 
@@ -17,6 +26,14 @@ namespace osu.Game.Rulesets.Catch.Edit
 {
     public class CatchHitObjectComposer : HitObjectComposer<CatchHitObject>
     {
+        private const float distance_snap_radius = 50;
+
+        private CatchDistanceSnapGrid distanceSnapGrid;
+
+        private readonly Bindable<TernaryState> distanceSnapToggle = new Bindable<TernaryState>();
+
+        private InputManager inputManager;
+
         public CatchHitObjectComposer(CatchRuleset ruleset)
             : base(ruleset)
         {
@@ -30,6 +47,27 @@ namespace osu.Game.Rulesets.Catch.Edit
                 RelativeSizeAxes = Axes.Both,
                 PlayfieldBorderStyle = { Value = PlayfieldBorderStyle.Corners }
             });
+
+            LayerBelowRuleset.Add(distanceSnapGrid = new CatchDistanceSnapGrid(new[]
+            {
+                0.0,
+                Catcher.BASE_DASH_SPEED, -Catcher.BASE_DASH_SPEED,
+                Catcher.BASE_WALK_SPEED, -Catcher.BASE_WALK_SPEED,
+            }));
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            inputManager = GetContainingInputManager();
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            updateDistanceSnapGrid();
         }
 
         protected override DrawableRuleset<CatchHitObject> CreateDrawableRuleset(Ruleset ruleset, IBeatmap beatmap, IReadOnlyList<Mod> mods = null) =>
@@ -42,14 +80,95 @@ namespace osu.Game.Rulesets.Catch.Edit
             new BananaShowerCompositionTool()
         };
 
+        protected override IEnumerable<TernaryButton> CreateTernaryButtons() => base.CreateTernaryButtons().Concat(new[]
+        {
+            new TernaryButton(distanceSnapToggle, "Distance Snap", () => new SpriteIcon { Icon = FontAwesome.Solid.Ruler })
+        });
+
         public override SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition)
         {
             var result = base.SnapScreenSpacePositionToValidTime(screenSpacePosition);
-            // TODO: implement position snap
             result.ScreenSpacePosition.X = screenSpacePosition.X;
+
+            if (distanceSnapGrid.IsPresent && distanceSnapGrid.GetSnappedPosition(result.ScreenSpacePosition) is SnapResult snapResult &&
+                Vector2.Distance(snapResult.ScreenSpacePosition, result.ScreenSpacePosition) < distance_snap_radius)
+            {
+                result = snapResult;
+            }
+
             return result;
         }
 
         protected override ComposeBlueprintContainer CreateBlueprintContainer() => new CatchBlueprintContainer(this);
+
+        [CanBeNull]
+        private PalpableCatchHitObject getLastSnappableHitObject(double time)
+        {
+            var hitObject = EditorBeatmap.HitObjects.OfType<CatchHitObject>().LastOrDefault(h => h.GetEndTime() < time && !(h is BananaShower));
+
+            switch (hitObject)
+            {
+                case Fruit fruit:
+                    return fruit;
+
+                case JuiceStream juiceStream:
+                    return juiceStream.NestedHitObjects.OfType<PalpableCatchHitObject>().LastOrDefault(h => !(h is TinyDroplet));
+
+                default:
+                    return null;
+            }
+        }
+
+        [CanBeNull]
+        private PalpableCatchHitObject getDistanceSnapGridSourceHitObject()
+        {
+            switch (BlueprintContainer.CurrentTool)
+            {
+                case SelectTool _:
+                    if (EditorBeatmap.SelectedHitObjects.Count == 0)
+                        return null;
+
+                    double minTime = EditorBeatmap.SelectedHitObjects.Min(hitObject => hitObject.StartTime);
+                    return getLastSnappableHitObject(minTime);
+
+                case FruitCompositionTool _:
+                case JuiceStreamCompositionTool _:
+                    if (!CursorInPlacementArea)
+                        return null;
+
+                    if (EditorBeatmap.PlacementObject.Value is JuiceStream)
+                    {
+                        // Juice stream path is not subject to snapping.
+                        return null;
+                    }
+
+                    double timeAtCursor = ((CatchPlayfield)Playfield).TimeAtScreenSpacePosition(inputManager.CurrentState.Mouse.Position);
+                    return getLastSnappableHitObject(timeAtCursor);
+
+                default:
+                    return null;
+            }
+        }
+
+        private void updateDistanceSnapGrid()
+        {
+            if (distanceSnapToggle.Value != TernaryState.True)
+            {
+                distanceSnapGrid.Hide();
+                return;
+            }
+
+            var sourceHitObject = getDistanceSnapGridSourceHitObject();
+
+            if (sourceHitObject == null)
+            {
+                distanceSnapGrid.Hide();
+                return;
+            }
+
+            distanceSnapGrid.Show();
+            distanceSnapGrid.StartTime = sourceHitObject.GetEndTime();
+            distanceSnapGrid.StartX = sourceHitObject.EffectiveX;
+        }
     }
 }

osu.Game.Rulesets.Catch/Edit/Checks/CheckBananaShowerGap.cs

@@ -0,0 +1,102 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Edit.Checks.Components;
+using osu.Game.Rulesets.Objects;
+
+namespace osu.Game.Rulesets.Catch.Edit.Checks
+{
+    /// <summary>
+    /// Check the spinner/banana shower gaps specified in the osu!catch difficulty specific ranking criteria.
+    /// </summary>
+    public class CheckBananaShowerGap : ICheck
+    {
+        private static readonly Dictionary<DifficultyRating, (int startGap, int endGap)> spinner_delta_threshold = new Dictionary<DifficultyRating, (int, int)>
+        {
+            [DifficultyRating.Easy] = (250, 250),
+            [DifficultyRating.Normal] = (250, 250),
+            [DifficultyRating.Hard] = (125, 250),
+            [DifficultyRating.Insane] = (125, 125),
+            [DifficultyRating.Expert] = (62, 125),
+            [DifficultyRating.ExpertPlus] = (62, 125)
+        };
+
+        public CheckMetadata Metadata { get; } = new CheckMetadata(CheckCategory.Compose, "Too short spinner gap");
+
+        public IEnumerable<IssueTemplate> PossibleTemplates => new IssueTemplate[]
+        {
+            new IssueTemplateBananaShowerStartGap(this),
+            new IssueTemplateBananaShowerEndGap(this)
+        };
+
+        public IEnumerable<Issue> Run(BeatmapVerifierContext context)
+        {
+            var hitObjects = context.Beatmap.HitObjects;
+            (int expectedStartDelta, int expectedEndDelta) = spinner_delta_threshold[context.InterpretedDifficulty];
+
+            for (int i = 0; i < hitObjects.Count - 1; ++i)
+            {
+                if (!(hitObjects[i] is BananaShower bananaShower))
+                    continue;
+
+                // Skip if the previous hitobject is a banana shower, consecutive spinners are allowed
+                if (i != 0 && hitObjects[i - 1] is CatchHitObject previousHitObject && !(previousHitObject is BananaShower))
+                {
+                    double spinnerStartDelta = bananaShower.StartTime - previousHitObject.GetEndTime();
+
+                    if (spinnerStartDelta < expectedStartDelta)
+                    {
+                        yield return new IssueTemplateBananaShowerStartGap(this)
+                            .Create(spinnerStartDelta, expectedStartDelta, bananaShower, previousHitObject);
+                    }
+                }
+
+                // Skip if the next hitobject is a banana shower, consecutive spinners are allowed
+                if (hitObjects[i + 1] is CatchHitObject nextHitObject && !(nextHitObject is BananaShower))
+                {
+                    double spinnerEndDelta = nextHitObject.StartTime - bananaShower.EndTime;
+
+                    if (spinnerEndDelta < expectedEndDelta)
+                    {
+                        yield return new IssueTemplateBananaShowerEndGap(this)
+                            .Create(spinnerEndDelta, expectedEndDelta, bananaShower, nextHitObject);
+                    }
+                }
+            }
+        }
+
+        public abstract class IssueTemplateBananaShowerGap : IssueTemplate
+        {
+            protected IssueTemplateBananaShowerGap(ICheck check, IssueType issueType, string unformattedMessage)
+                : base(check, issueType, unformattedMessage)
+            {
+            }
+
+            public Issue Create(double deltaTime, int expectedDeltaTime, params HitObject[] hitObjects)
+            {
+                return new Issue(hitObjects, this, Math.Floor(deltaTime), expectedDeltaTime);
+            }
+        }
+
+        public class IssueTemplateBananaShowerStartGap : IssueTemplateBananaShowerGap
+        {
+            public IssueTemplateBananaShowerStartGap(ICheck check)
+                : base(check, IssueType.Problem, "There is only {0} ms between the start of the spinner and the last object, it should not be less than {1} ms.")
+            {
+            }
+        }
+
+        public class IssueTemplateBananaShowerEndGap : IssueTemplateBananaShowerGap
+        {
+            public IssueTemplateBananaShowerEndGap(ICheck check)
+                : base(check, IssueType.Problem, "There is only {0} ms between the end of the spinner and the next object, it should not be less than {1} ms.")
+            {
+            }
+        }
+    }
+}

osu.Game.Rulesets.Catch/Edit/DrawableCatchEditorRuleset.cs

@@ -16,6 +16,6 @@ namespace osu.Game.Rulesets.Catch.Edit
         {
         }
 
-        protected override Playfield CreatePlayfield() => new CatchEditorPlayfield(Beatmap.BeatmapInfo.BaseDifficulty);
+        protected override Playfield CreatePlayfield() => new CatchEditorPlayfield(Beatmap.Difficulty);
     }
 }

osu.Game.Rulesets.Catch/Mods/CatchModAutoplay.cs

@@ -3,10 +3,10 @@
 
 using System.Collections.Generic;
 using osu.Game.Beatmaps;
+using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Rulesets.Catch.Replays;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Scoring;
-using osu.Game.Users;
 
 namespace osu.Game.Rulesets.Catch.Mods
 {
@@ -14,7 +14,7 @@ namespace osu.Game.Rulesets.Catch.Mods
     {
         public override Score CreateReplayScore(IBeatmap beatmap, IReadOnlyList<Mod> mods) => new Score
         {
-            ScoreInfo = new ScoreInfo { User = new User { Username = "osu!salad!" } },
+            ScoreInfo = new ScoreInfo { User = new APIUser { Username = "osu!salad" } },
             Replay = new CatchAutoGenerator(beatmap).Generate(),
         };
     }

osu.Game.Rulesets.Catch/Mods/CatchModCinema.cs

@@ -3,11 +3,11 @@
 
 using System.Collections.Generic;
 using osu.Game.Beatmaps;
+using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Rulesets.Catch.Objects;
 using osu.Game.Rulesets.Catch.Replays;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Scoring;
-using osu.Game.Users;
 
 namespace osu.Game.Rulesets.Catch.Mods
 {
@@ -15,7 +15,7 @@ namespace osu.Game.Rulesets.Catch.Mods
     {
         public override Score CreateReplayScore(IBeatmap beatmap, IReadOnlyList<Mod> mods) => new Score
         {
-            ScoreInfo = new ScoreInfo { User = new User { Username = "osu!salad!" } },
+            ScoreInfo = new ScoreInfo { User = new APIUser { Username = "osu!salad" } },
             Replay = new CatchAutoGenerator(beatmap).Generate(),
         };
     }

osu.Game.Rulesets.Catch/Mods/CatchModHidden.cs

@@ -52,8 +52,8 @@ namespace osu.Game.Rulesets.Catch.Mods
         {
             var hitObject = drawable.HitObject;
 
-            var offset = hitObject.TimePreempt * fade_out_offset_multiplier;
-            var duration = offset - hitObject.TimePreempt * fade_out_duration_multiplier;
+            double offset = hitObject.TimePreempt * fade_out_offset_multiplier;
+            double duration = offset - hitObject.TimePreempt * fade_out_duration_multiplier;
 
             using (drawable.BeginAbsoluteSequence(hitObject.StartTime - offset))
                 drawable.FadeOut(duration);

osu.Game.Rulesets.Catch/Mods/CatchModNoScope.cs

@@ -0,0 +1,40 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using osu.Framework.Bindables;
+using osu.Game.Rulesets.Mods;
+using osu.Framework.Utils;
+using osu.Game.Configuration;
+using osu.Game.Overlays.Settings;
+using osu.Game.Rulesets.Catch.UI;
+using osu.Game.Rulesets.UI;
+
+namespace osu.Game.Rulesets.Catch.Mods
+{
+    public class CatchModNoScope : ModNoScope, IUpdatableByPlayfield
+    {
+        public override string Description => "Where's the catcher?";
+
+        [SettingSource(
+            "Hidden at combo",
+            "The combo count at which the catcher becomes completely hidden",
+            SettingControlType = typeof(SettingsSlider<int, HiddenComboSlider>)
+        )]
+        public override BindableInt HiddenComboCount { get; } = new BindableInt
+        {
+            Default = 10,
+            Value = 10,
+            MinValue = 0,
+            MaxValue = 50,
+        };
+
+        public void Update(Playfield playfield)
+        {
+            var catchPlayfield = (CatchPlayfield)playfield;
+            bool shouldAlwaysShowCatcher = IsBreakTime.Value;
+            float targetAlpha = shouldAlwaysShowCatcher ? 1 : ComboBasedAlpha;
+            catchPlayfield.CatcherArea.Alpha = (float)Interpolation.Lerp(catchPlayfield.CatcherArea.Alpha, targetAlpha, Math.Clamp(catchPlayfield.Time.Elapsed / TRANSITION_DURATION, 0, 1));
+        }
+    }
+}

osu.Game.Rulesets.Catch/Objects/CatchHitObject.cs

@@ -128,11 +128,11 @@ namespace osu.Game.Rulesets.Catch.Objects
         /// </summary>
         public int RandomSeed => (int)StartTime;
 
-        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, IBeatmapDifficultyInfo difficulty)
         {
             base.ApplyDefaultsToSelf(controlPointInfo, difficulty);
 
-            TimePreempt = (float)BeatmapDifficulty.DifficultyRange(difficulty.ApproachRate, 1800, 1200, 450);
+            TimePreempt = (float)IBeatmapDifficultyInfo.DifficultyRange(difficulty.ApproachRate, 1800, 1200, 450);
 
             Scale = (1.0f - 0.7f * (difficulty.CircleSize - 5) / 5) / 2;
         }

osu.Game.Rulesets.Catch/Objects/JuiceStream.cs

@@ -37,14 +37,13 @@ namespace osu.Game.Rulesets.Catch.Objects
         /// </summary>
         public double SpanDuration => Duration / this.SpanCount();
 
-        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, IBeatmapDifficultyInfo difficulty)
         {
             base.ApplyDefaultsToSelf(controlPointInfo, difficulty);
 
             TimingControlPoint timingPoint = controlPointInfo.TimingPointAt(StartTime);
-            DifficultyControlPoint difficultyPoint = controlPointInfo.DifficultyPointAt(StartTime);
 
-            double scoringDistance = base_scoring_distance * difficulty.SliderMultiplier * difficultyPoint.SpeedMultiplier;
+            double scoringDistance = base_scoring_distance * difficulty.SliderMultiplier * DifficultyControlPoint.SliderVelocity;
 
             Velocity = scoringDistance / timingPoint.BeatLength;
             TickDistance = scoringDistance / difficulty.SliderTickRate;
@@ -146,7 +145,7 @@ namespace osu.Game.Rulesets.Catch.Objects
 
         public double Distance => Path.Distance;
 
-        public List<IList<HitSampleInfo>> NodeSamples { get; set; } = new List<IList<HitSampleInfo>>();
+        public IList<IList<HitSampleInfo>> NodeSamples { get; set; } = new List<IList<HitSampleInfo>>();
 
         public double? LegacyLastTickOffset { get; set; }
     }

osu.Game.Rulesets.Catch/Replays/CatchAutoGenerator.cs

@@ -26,9 +26,6 @@ namespace osu.Game.Rulesets.Catch.Replays
             if (Beatmap.HitObjects.Count == 0)
                 return;
 
-            // todo: add support for HT DT
-            const double dash_speed = Catcher.BASE_SPEED;
-            const double movement_speed = dash_speed / 2;
             float lastPosition = CatchPlayfield.CENTER_X;
             double lastTime = 0;
 
@@ -47,8 +44,8 @@ namespace osu.Game.Rulesets.Catch.Replays
                 // The case where positionChange > 0 and timeAvailable == 0 results in PositiveInfinity which provides expected beheaviour.
                 double speedRequired = positionChange == 0 ? 0 : positionChange / timeAvailable;
 
-                bool dashRequired = speedRequired > movement_speed;
-                bool impossibleJump = speedRequired > movement_speed * 2;
+                bool dashRequired = speedRequired > Catcher.BASE_WALK_SPEED;
+                bool impossibleJump = speedRequired > Catcher.BASE_DASH_SPEED;
 
                 // todo: get correct catcher size, based on difficulty CS.
                 const float catcher_width_half = Catcher.BASE_SIZE * 0.3f * 0.5f;
@@ -73,7 +70,7 @@ namespace osu.Game.Rulesets.Catch.Replays
                 else if (dashRequired)
                 {
                     // we do a movement in two parts - the dash part then the normal part...
-                    double timeAtNormalSpeed = positionChange / movement_speed;
+                    double timeAtNormalSpeed = positionChange / Catcher.BASE_WALK_SPEED;
                     double timeWeNeedToSave = timeAtNormalSpeed - timeAvailable;
                     double timeAtDashSpeed = timeWeNeedToSave / 2;
 
@@ -86,7 +83,7 @@ namespace osu.Game.Rulesets.Catch.Replays
                 }
                 else
                 {
-                    double timeBefore = positionChange / movement_speed;
+                    double timeBefore = positionChange / Catcher.BASE_WALK_SPEED;
 
                     addFrame(h.StartTime - timeBefore, lastPosition);
                     addFrame(h.StartTime, h.EffectiveX);

osu.Game.Rulesets.Catch/Replays/CatchFramedReplayInputHandler.cs

@@ -21,7 +21,7 @@ namespace osu.Game.Rulesets.Catch.Replays
 
         public override void CollectPendingInputs(List<IInput> inputs)
         {
-            var position = Interpolation.ValueAt(CurrentTime, StartFrame.Position, EndFrame.Position, StartFrame.Time, EndFrame.Time);
+            float position = Interpolation.ValueAt(CurrentTime, StartFrame.Position, EndFrame.Position, StartFrame.Time, EndFrame.Time);
 
             inputs.Add(new CatchReplayState
             {

osu.Game.Rulesets.Catch/Skinning/Legacy/CatchLegacySkinTransformer.cs

@@ -66,7 +66,7 @@ namespace osu.Game.Rulesets.Catch.Skinning.Legacy
                         return null;
 
                     case CatchSkinComponents.Catcher:
-                        var version = GetConfig<LegacySkinConfiguration.LegacySetting, decimal>(LegacySkinConfiguration.LegacySetting.Version)?.Value ?? 1;
+                        decimal version = GetConfig<SkinConfiguration.LegacySetting, decimal>(SkinConfiguration.LegacySetting.Version)?.Value ?? 1;
 
                         if (version < 2.3m)
                         {

osu.Game.Rulesets.Catch/UI/CatchPlayfield.cs

@@ -34,9 +34,9 @@ namespace osu.Game.Rulesets.Catch.UI
 
         internal CatcherArea CatcherArea { get; private set; }
 
-        private readonly BeatmapDifficulty difficulty;
+        private readonly IBeatmapDifficultyInfo difficulty;
 
-        public CatchPlayfield(BeatmapDifficulty difficulty)
+        public CatchPlayfield(IBeatmapDifficultyInfo difficulty)
         {
             this.difficulty = difficulty;
         }

osu.Game.Rulesets.Catch/UI/Catcher.cs

@@ -57,14 +57,19 @@ namespace osu.Game.Rulesets.Catch.UI
         public bool CatchFruitOnPlate { get; set; } = true;
 
         /// <summary>
-        /// The relative space to cover in 1 millisecond. based on 1 game pixel per millisecond as in osu-stable.
+        /// The speed of the catcher when the catcher is dashing.
         /// </summary>
-        public const double BASE_SPEED = 1.0;
+        public const double BASE_DASH_SPEED = 1.0;
 
         /// <summary>
-        /// The current speed of the catcher.
+        /// The speed of the catcher when the catcher is not dashing.
         /// </summary>
-        public double Speed => (Dashing ? 1 : 0.5) * BASE_SPEED * hyperDashModifier;
+        public const double BASE_WALK_SPEED = 0.5;
+
+        /// <summary>
+        /// The current speed of the catcher with the hyper-dash modifier applied.
+        /// </summary>
+        public double Speed => (Dashing ? BASE_DASH_SPEED : BASE_WALK_SPEED) * hyperDashModifier;
 
         /// <summary>
         /// The amount by which caught fruit should be scaled down to fit on the plate.
@@ -124,7 +129,7 @@ namespace osu.Game.Rulesets.Catch.UI
         private readonly DrawablePool<CaughtBanana> caughtBananaPool;
         private readonly DrawablePool<CaughtDroplet> caughtDropletPool;
 
-        public Catcher([NotNull] DroppedObjectContainer droppedObjectTarget, BeatmapDifficulty difficulty = null)
+        public Catcher([NotNull] DroppedObjectContainer droppedObjectTarget, IBeatmapDifficultyInfo difficulty = null)
         {
             this.droppedObjectTarget = droppedObjectTarget;
 
@@ -172,7 +177,7 @@ namespace osu.Game.Rulesets.Catch.UI
         /// <summary>
         /// Calculates the scale of the catcher based off the provided beatmap difficulty.
         /// </summary>
-        private static Vector2 calculateScale(BeatmapDifficulty difficulty) => new Vector2(1.0f - 0.7f * (difficulty.CircleSize - 5) / 5);
+        private static Vector2 calculateScale(IBeatmapDifficultyInfo difficulty) => new Vector2(1.0f - 0.7f * (difficulty.CircleSize - 5) / 5);
 
         /// <summary>
         /// Calculates the width of the area used for attempting catches in gameplay.
@@ -184,7 +189,7 @@ namespace osu.Game.Rulesets.Catch.UI
         /// Calculates the width of the area used for attempting catches in gameplay.
         /// </summary>
         /// <param name="difficulty">The beatmap difficulty.</param>
-        public static float CalculateCatchWidth(BeatmapDifficulty difficulty) => CalculateCatchWidth(calculateScale(difficulty));
+        public static float CalculateCatchWidth(IBeatmapDifficultyInfo difficulty) => CalculateCatchWidth(calculateScale(difficulty));
 
         /// <summary>
         /// Determine if this catcher can catch a <see cref="CatchHitObject"/> in the current position.
@@ -205,6 +210,7 @@ namespace osu.Game.Rulesets.Catch.UI
             catchResult.CatcherAnimationState = CurrentState;
             catchResult.CatcherHyperDash = HyperDashing;
 
+            // Ignore JuiceStreams and BananaShowers
             if (!(drawableObject is DrawablePalpableCatchHitObject palpableObject)) return;
 
             var hitObject = palpableObject.HitObject;
@@ -226,11 +232,11 @@ namespace osu.Game.Rulesets.Catch.UI
             if (result.IsHit && hitObject.HyperDash)
             {
                 var target = hitObject.HyperDashTarget;
-                var timeDifference = target.StartTime - hitObject.StartTime;
+                double timeDifference = target.StartTime - hitObject.StartTime;
                 double positionDifference = target.EffectiveX - X;
-                var velocity = positionDifference / Math.Max(1.0, timeDifference - 1000.0 / 60.0);
+                double velocity = positionDifference / Math.Max(1.0, timeDifference - 1000.0 / 60.0);
 
-                SetHyperDashState(Math.Abs(velocity), target.EffectiveX);
+                SetHyperDashState(Math.Abs(velocity) / BASE_DASH_SPEED, target.EffectiveX);
             }
             else
                 SetHyperDashState();
@@ -239,6 +245,14 @@ namespace osu.Game.Rulesets.Catch.UI
                 CurrentState = hitObject.Kiai ? CatcherAnimationState.Kiai : CatcherAnimationState.Idle;
             else if (!(hitObject is Banana))
                 CurrentState = CatcherAnimationState.Fail;
+
+            if (palpableObject.HitObject.LastInCombo)
+            {
+                if (result.Judgement is CatchJudgement catchJudgement && catchJudgement.ShouldExplodeFor(result))
+                    Explode();
+                else
+                    Drop();
+            }
         }
 
         public void OnRevertResult(DrawableCatchHitObject drawableObject, JudgementResult result)
@@ -266,7 +280,7 @@ namespace osu.Game.Rulesets.Catch.UI
         /// <param name="targetPosition">When this catcher crosses this position, this catcher ends hyper-dashing.</param>
         public void SetHyperDashState(double modifier = 1, float targetPosition = -1)
         {
-            var wasHyperDashing = HyperDashing;
+            bool wasHyperDashing = HyperDashing;
 
             if (modifier <= 1 || X == targetPosition)
             {

osu.Game.Rulesets.Catch/UI/CatcherArea.cs

@@ -6,11 +6,9 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Input.Bindings;
 using osu.Framework.Input.Events;
-using osu.Game.Rulesets.Catch.Judgements;
 using osu.Game.Rulesets.Catch.Objects.Drawables;
 using osu.Game.Rulesets.Catch.Replays;
 using osu.Game.Rulesets.Judgements;
-using osu.Game.Rulesets.Scoring;
 using osu.Game.Rulesets.UI;
 using osuTK;
 
@@ -72,18 +70,6 @@ namespace osu.Game.Rulesets.Catch.UI
         public void OnNewResult(DrawableCatchHitObject hitObject, JudgementResult result)
         {
             Catcher.OnNewResult(hitObject, result);
-
-            if (!result.Type.IsScorable())
-                return;
-
-            if (hitObject.HitObject.LastInCombo)
-            {
-                if (result.Judgement is CatchJudgement catchJudgement && catchJudgement.ShouldExplodeFor(result))
-                    Catcher.Explode();
-                else
-                    Catcher.Drop();
-            }
-
             comboDisplay.OnNewResult(hitObject, result);
         }
 

osu.Game.Rulesets.Catch/UI/DrawableCatchRuleset.cs

@@ -27,14 +27,14 @@ namespace osu.Game.Rulesets.Catch.UI
             : base(ruleset, beatmap, mods)
         {
             Direction.Value = ScrollingDirection.Down;
-            TimeRange.Value = BeatmapDifficulty.DifficultyRange(beatmap.BeatmapInfo.BaseDifficulty.ApproachRate, 1800, 1200, 450);
+            TimeRange.Value = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.ApproachRate, 1800, 1200, 450);
         }
 
         protected override ReplayInputHandler CreateReplayInputHandler(Replay replay) => new CatchFramedReplayInputHandler(replay);
 
         protected override ReplayRecorder CreateReplayRecorder(Score score) => new CatchReplayRecorder(score, (CatchPlayfield)Playfield);
 
-        protected override Playfield CreatePlayfield() => new CatchPlayfield(Beatmap.BeatmapInfo.BaseDifficulty);
+        protected override Playfield CreatePlayfield() => new CatchPlayfield(Beatmap.Difficulty);
 
         public override PlayfieldAdjustmentContainer CreatePlayfieldAdjustmentContainer() => new CatchPlayfieldAdjustmentContainer();
 

osu.Game.Rulesets.Mania.Tests.iOS/Application.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.iOS;
 using UIKit;
 
 namespace osu.Game.Rulesets.Mania.Tests.iOS
@@ -9,7 +10,7 @@ namespace osu.Game.Rulesets.Mania.Tests.iOS
     {
         public static void Main(string[] args)
         {
-            UIApplication.Main(args, "GameUIApplication", "AppDelegate");
+            UIApplication.Main(args, typeof(GameUIApplication), typeof(AppDelegate));
         }
     }
 }

osu.Game.Rulesets.Mania.Tests/Editor/ManiaPlacementBlueprintTestScene.cs

@@ -43,7 +43,7 @@ namespace osu.Game.Rulesets.Mania.Tests.Editor
 
         protected override SnapResult SnapForBlueprint(PlacementBlueprint blueprint)
         {
-            var time = column.TimeAtScreenSpacePosition(InputManager.CurrentState.Mouse.Position);
+            double time = column.TimeAtScreenSpacePosition(InputManager.CurrentState.Mouse.Position);
             var pos = column.ScreenSpacePositionAtTime(time);
 
             return new SnapResult(pos, time, column);

osu.Game.Rulesets.Mania.Tests/Editor/TestSceneManiaBeatSnapGrid.cs

@@ -13,6 +13,7 @@ using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Mania.Beatmaps;
 using osu.Game.Rulesets.Mania.Edit;
 using osu.Game.Rulesets.Mania.UI;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.UI;
 using osu.Game.Rulesets.UI.Scrolling;
@@ -101,27 +102,27 @@ namespace osu.Game.Rulesets.Mania.Tests.Editor
             throw new System.NotImplementedException();
         }
 
-        public override float GetBeatSnapDistanceAt(double referenceTime)
+        public override float GetBeatSnapDistanceAt(HitObject referenceObject)
         {
             throw new System.NotImplementedException();
         }
 
-        public override float DurationToDistance(double referenceTime, double duration)
+        public override float DurationToDistance(HitObject referenceObject, double duration)
         {
             throw new System.NotImplementedException();
         }
 
-        public override double DistanceToDuration(double referenceTime, float distance)
+        public override double DistanceToDuration(HitObject referenceObject, float distance)
         {
             throw new System.NotImplementedException();
         }
 
-        public override double GetSnappedDurationFromDistance(double referenceTime, float distance)
+        public override double GetSnappedDurationFromDistance(HitObject referenceObject, float distance)
         {
             throw new System.NotImplementedException();
         }
 
-        public override float GetSnappedDistanceFromDistance(double referenceTime, float distance)
+        public override float GetSnappedDistanceFromDistance(HitObject referenceObject, float distance)
         {
             throw new System.NotImplementedException();
         }

osu.Game.Rulesets.Mania.Tests/Editor/TestSceneManiaComposeScreen.cs

@@ -22,6 +22,9 @@ namespace osu.Game.Rulesets.Mania.Tests.Editor
         [Resolved]
         private SkinManager skins { get; set; }
 
+        [Cached]
+        private EditorClipboard clipboard = new EditorClipboard();
+
         [SetUpSteps]
         public void SetUpSteps()
         {

osu.Game.Rulesets.Mania.Tests/ManiaBeatmapConversionTest.cs

@@ -111,7 +111,7 @@ namespace osu.Game.Rulesets.Mania.Tests
 
         public int CompareTo(ConvertValue other)
         {
-            var result = StartTime.CompareTo(other.StartTime);
+            int result = StartTime.CompareTo(other.StartTime);
 
             if (result != 0)
                 return result;

osu.Game.Rulesets.Mania.Tests/ManiaBeatmapSampleConversionTest.cs

@@ -38,7 +38,7 @@ namespace osu.Game.Rulesets.Mania.Tests
         private IList<string> getSampleNames(IList<HitSampleInfo> hitSampleInfo)
             => hitSampleInfo.Select(sample => sample.LookupNames.First()).ToList();
 
-        private IList<IList<string>> getNodeSampleNames(List<IList<HitSampleInfo>> hitSampleInfo)
+        private IList<IList<string>> getNodeSampleNames(IList<IList<HitSampleInfo>> hitSampleInfo)
             => hitSampleInfo?.Select(getSampleNames)
                             .ToList();
 

osu.Game.Rulesets.Mania.Tests/ManiaColumnTypeTest.cs

@@ -43,7 +43,7 @@ namespace osu.Game.Rulesets.Mania.Tests
 
         private IEnumerable<ColumnType> getResults(StageDefinition definition)
         {
-            for (var i = 0; i < definition.Columns; i++)
+            for (int i = 0; i < definition.Columns; i++)
                 yield return definition.GetTypeOfColumn(i);
         }
     }

osu.Game.Rulesets.Mania.Tests/ManiaDifficultyCalculatorTest.cs

@@ -22,7 +22,7 @@ namespace osu.Game.Rulesets.Mania.Tests
         public void TestClockRateAdjusted(double expected, string name)
             => Test(expected, name, new ManiaModDoubleTime());
 
-        protected override DifficultyCalculator CreateDifficultyCalculator(WorkingBeatmap beatmap) => new ManiaDifficultyCalculator(new ManiaRuleset(), beatmap);
+        protected override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new ManiaDifficultyCalculator(new ManiaRuleset().RulesetInfo, beatmap);
 
         protected override Ruleset CreateRuleset() => new ManiaRuleset();
     }

osu.Game.Rulesets.Mania.Tests/TestSceneHoldNoteInput.cs

@@ -388,7 +388,7 @@ namespace osu.Game.Rulesets.Mania.Tests
                     },
                 };
 
-                beatmap.ControlPointInfo.Add(0, new DifficultyControlPoint { SpeedMultiplier = 0.1f });
+                beatmap.ControlPointInfo.Add(0, new EffectControlPoint { ScrollSpeed = 0.1f });
             }
 
             AddStep("load player", () =>

osu.Game.Rulesets.Mania.Tests/TestSceneOutOfOrderHits.cs

@@ -148,7 +148,7 @@ namespace osu.Game.Rulesets.Mania.Tests
                     },
                 });
 
-                Beatmap.Value.Beatmap.ControlPointInfo.Add(0, new DifficultyControlPoint { SpeedMultiplier = 0.1f });
+                Beatmap.Value.Beatmap.ControlPointInfo.Add(0, new EffectControlPoint { ScrollSpeed = 0.1f });
 
                 var p = new ScoreAccessibleReplayPlayer(new Score { Replay = new Replay { Frames = frames } });
 

osu.Game.Rulesets.Mania.Tests/osu.Game.Rulesets.Mania.Tests.csproj

@@ -2,9 +2,9 @@
   <Import Project="..\osu.TestProject.props" />
   <ItemGroup Label="Package References">
     <PackageReference Include="Appveyor.TestLogger" Version="2.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
     <PackageReference Include="NUnit" Version="3.13.2" />
-    <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.1.0" />
     <PackageReference Update="Microsoft.EntityFrameworkCore.Sqlite" Version="2.1.4" />
   </ItemGroup>
   <PropertyGroup Label="Project">

osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs

@@ -42,8 +42,8 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
         {
             IsForCurrentRuleset = beatmap.BeatmapInfo.Ruleset.Equals(ruleset.RulesetInfo);
 
-            var roundedCircleSize = Math.Round(beatmap.BeatmapInfo.BaseDifficulty.CircleSize);
-            var roundedOverallDifficulty = Math.Round(beatmap.BeatmapInfo.BaseDifficulty.OverallDifficulty);
+            double roundedCircleSize = Math.Round(beatmap.Difficulty.CircleSize);
+            double roundedOverallDifficulty = Math.Round(beatmap.Difficulty.OverallDifficulty);
 
             if (IsForCurrentRuleset)
             {
@@ -71,9 +71,9 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
             originalTargetColumns = TargetColumns;
         }
 
-        public static int GetColumnCountForNonConvert(BeatmapInfo beatmap)
+        public static int GetColumnCountForNonConvert(BeatmapInfo beatmapInfo)
         {
-            var roundedCircleSize = Math.Round(beatmap.BaseDifficulty.CircleSize);
+            double roundedCircleSize = Math.Round(beatmapInfo.BaseDifficulty.CircleSize);
             return (int)Math.Max(1, roundedCircleSize);
         }
 
@@ -81,7 +81,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
 
         protected override Beatmap<ManiaHitObject> ConvertBeatmap(IBeatmap original, CancellationToken cancellationToken)
         {
-            BeatmapDifficulty difficulty = original.BeatmapInfo.BaseDifficulty;
+            IBeatmapDifficultyInfo difficulty = original.Difficulty;
 
             int seed = (int)MathF.Round(difficulty.DrainRate + difficulty.CircleSize) * 20 + (int)(difficulty.OverallDifficulty * 41.2) + (int)MathF.Round(difficulty.ApproachRate);
             Random = new FastRandom(seed);

osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/DistanceObjectPatternGenerator.cs

@@ -47,7 +47,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
             Debug.Assert(distanceData != null);
 
             TimingControlPoint timingPoint = beatmap.ControlPointInfo.TimingPointAt(hitObject.StartTime);
-            DifficultyControlPoint difficultyPoint = beatmap.ControlPointInfo.DifficultyPointAt(hitObject.StartTime);
+            DifficultyControlPoint difficultyPoint = hitObject.DifficultyControlPoint;
 
             double beatLength;
 #pragma warning disable 618
@@ -55,13 +55,13 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
 #pragma warning restore 618
                 beatLength = timingPoint.BeatLength * legacyDifficultyPoint.BpmMultiplier;
             else
-                beatLength = timingPoint.BeatLength / difficultyPoint.SpeedMultiplier;
+                beatLength = timingPoint.BeatLength / difficultyPoint.SliderVelocity;
 
             SpanCount = repeatsData?.SpanCount() ?? 1;
             StartTime = (int)Math.Round(hitObject.StartTime);
 
             // This matches stable's calculation.
-            EndTime = (int)Math.Floor(StartTime + distanceData.Distance * beatLength * SpanCount * 0.01 / beatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier);
+            EndTime = (int)Math.Floor(StartTime + distanceData.Distance * beatLength * SpanCount * 0.01 / beatmap.Difficulty.SliderMultiplier);
 
             SegmentDuration = (EndTime - StartTime) / SpanCount;
         }
@@ -488,12 +488,12 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
         /// Retrieves the list of node samples that occur at time greater than or equal to <paramref name="time"/>.
         /// </summary>
         /// <param name="time">The time to retrieve node samples at.</param>
-        private List<IList<HitSampleInfo>> nodeSamplesAt(int time)
+        private IList<IList<HitSampleInfo>> nodeSamplesAt(int time)
         {
             if (!(HitObject is IHasPathWithRepeats curveData))
                 return null;
 
-            var index = SegmentDuration == 0 ? 0 : (time - StartTime) / SegmentDuration;
+            int index = SegmentDuration == 0 ? 0 : (time - StartTime) / SegmentDuration;
 
             // avoid slicing the list & creating copies, if at all possible.
             return index == 0 ? curveData.NodeSamples : curveData.NodeSamples.Skip(index).ToList();

osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/HitObjectPatternGenerator.cs

@@ -302,7 +302,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
 
             var pattern = new Pattern();
 
-            int noteCount = getRandomNoteCountMirrored(centreProbability, p2, p3, out var addToCentre);
+            int noteCount = getRandomNoteCountMirrored(centreProbability, p2, p3, out bool addToCentre);
 
             int columnLimit = (TotalColumns % 2 == 0 ? TotalColumns : TotalColumns - 1) / 2;
             int nextColumn = GetRandomColumn(upperBound: columnLimit);

osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/PatternGenerator.cs

@@ -111,7 +111,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
                 if (drainTime == 0)
                     drainTime = 10000;
 
-                BeatmapDifficulty difficulty = OriginalBeatmap.BeatmapInfo.BaseDifficulty;
+                IBeatmapDifficultyInfo difficulty = OriginalBeatmap.Difficulty;
                 conversionDifficulty = ((difficulty.DrainRate + Math.Clamp(difficulty.ApproachRate, 4, 7)) / 1.5 + (double)OriginalBeatmap.HitObjects.Count / drainTime * 9f) / 38f * 5f / 1.15;
                 conversionDifficulty = Math.Min(conversionDifficulty.Value, 12);
 
@@ -149,7 +149,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
         {
             lowerBound ??= RandomStart;
             upperBound ??= TotalColumns;
-            nextColumn ??= (_ => GetRandomColumn(lowerBound, upperBound));
+            nextColumn ??= _ => GetRandomColumn(lowerBound, upperBound);
 
             // Check for the initial column
             if (isValid(initialColumn))
@@ -176,7 +176,19 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
 
             return initialColumn;
 
-            bool isValid(int column) => validation?.Invoke(column) != false && !patterns.Any(p => p.ColumnHasObject(column));
+            bool isValid(int column)
+            {
+                if (validation?.Invoke(column) == false)
+                    return false;
+
+                foreach (var p in patterns)
+                {
+                    if (p.ColumnHasObject(column))
+                        return false;
+                }
+
+                return true;
+            }
         }
 
         /// <summary>

osu.Game.Rulesets.Mania/Beatmaps/Patterns/Pattern.cs

@@ -12,46 +12,68 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns
     /// </summary>
     internal class Pattern
     {
-        private readonly List<ManiaHitObject> hitObjects = new List<ManiaHitObject>();
+        private List<ManiaHitObject> hitObjects;
+        private HashSet<int> containedColumns;
 
         /// <summary>
         /// All the hit objects contained in this pattern.
         /// </summary>
-        public IEnumerable<ManiaHitObject> HitObjects => hitObjects;
+        public IEnumerable<ManiaHitObject> HitObjects => hitObjects ?? Enumerable.Empty<ManiaHitObject>();
 
         /// <summary>
         /// Check whether a column of this patterns contains a hit object.
         /// </summary>
         /// <param name="column">The column index.</param>
         /// <returns>Whether the column with index <paramref name="column"/> contains a hit object.</returns>
-        public bool ColumnHasObject(int column) => hitObjects.Exists(h => h.Column == column);
+        public bool ColumnHasObject(int column) => containedColumns?.Contains(column) == true;
 
         /// <summary>
         /// Amount of columns taken up by hit objects in this pattern.
         /// </summary>
-        public int ColumnWithObjects => HitObjects.GroupBy(h => h.Column).Count();
+        public int ColumnWithObjects => containedColumns?.Count ?? 0;
 
         /// <summary>
         /// Adds a hit object to this pattern.
         /// </summary>
         /// <param name="hitObject">The hit object to add.</param>
-        public void Add(ManiaHitObject hitObject) => hitObjects.Add(hitObject);
+        public void Add(ManiaHitObject hitObject)
+        {
+            prepareStorage();
+
+            hitObjects.Add(hitObject);
+            containedColumns.Add(hitObject.Column);
+        }
 
         /// <summary>
         /// Copies hit object from another pattern to this one.
         /// </summary>
         /// <param name="other">The other pattern.</param>
-        public void Add(Pattern other) => hitObjects.AddRange(other.HitObjects);
+        public void Add(Pattern other)
+        {
+            prepareStorage();
+
+            if (other.hitObjects != null)
+            {
+                hitObjects.AddRange(other.hitObjects);
+
+                foreach (var h in other.hitObjects)
+                    containedColumns.Add(h.Column);
+            }
+        }
 
         /// <summary>
         /// Clears this pattern, removing all hit objects.
         /// </summary>
-        public void Clear() => hitObjects.Clear();
+        public void Clear()
+        {
+            hitObjects?.Clear();
+            containedColumns?.Clear();
+        }
 
-        /// <summary>
-        /// Removes a hit object from this pattern.
-        /// </summary>
-        /// <param name="hitObject">The hit object to remove.</param>
-        public bool Remove(ManiaHitObject hitObject) => hitObjects.Remove(hitObject);
+        private void prepareStorage()
+        {
+            hitObjects ??= new List<ManiaHitObject>();
+            containedColumns ??= new HashSet<int>();
+        }
     }
 }

osu.Game.Rulesets.Mania/Configuration/ManiaRulesetConfigManager.cs

@@ -28,7 +28,12 @@ namespace osu.Game.Rulesets.Mania.Configuration
         public override TrackedSettings CreateTrackedSettings() => new TrackedSettings
         {
             new TrackedSetting<double>(ManiaRulesetSetting.ScrollTime,
-                v => new SettingDescription(v, "Scroll Speed", $"{(int)Math.Round(DrawableManiaRuleset.MAX_TIME_RANGE / v)} ({v}ms)"))
+                scrollTime => new SettingDescription(
+                    rawValue: scrollTime,
+                    name: "Scroll Speed",
+                    value: $"{(int)Math.Round(DrawableManiaRuleset.MAX_TIME_RANGE / scrollTime)} ({scrollTime}ms)"
+                )
+            )
         };
     }
 

osu.Game.Rulesets.Mania/Difficulty/ManiaDifficultyAttributes.cs

@@ -1,13 +1,38 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.Collections.Generic;
+using Newtonsoft.Json;
 using osu.Game.Rulesets.Difficulty;
 
 namespace osu.Game.Rulesets.Mania.Difficulty
 {
     public class ManiaDifficultyAttributes : DifficultyAttributes
     {
+        [JsonProperty("great_hit_window")]
         public double GreatHitWindow { get; set; }
+
+        [JsonProperty("score_multiplier")]
         public double ScoreMultiplier { get; set; }
+
+        public override IEnumerable<(int attributeId, object value)> ToDatabaseAttributes()
+        {
+            foreach (var v in base.ToDatabaseAttributes())
+                yield return v;
+
+            // Todo: osu!mania doesn't output MaxCombo attribute for some reason.
+            yield return (ATTRIB_ID_STRAIN, StarRating);
+            yield return (ATTRIB_ID_GREAT_HIT_WINDOW, GreatHitWindow);
+            yield return (ATTRIB_ID_SCORE_MULTIPLIER, ScoreMultiplier);
+        }
+
+        public override void FromDatabaseAttributes(IReadOnlyDictionary<int, double> values)
+        {
+            base.FromDatabaseAttributes(values);
+
+            StarRating = values[ATTRIB_ID_STRAIN];
+            GreatHitWindow = values[ATTRIB_ID_GREAT_HIT_WINDOW];
+            ScoreMultiplier = values[ATTRIB_ID_SCORE_MULTIPLIER];
+        }
     }
 }