From 95c72524677527dfe6b3db4ed62723804b3ade21 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Dach?= <dach.bartlomiej@gmail.com>
Date: Tue, 2 Sep 2025 14:43:41 +0200
Subject: [PATCH 1/2] Add failing test case

---
 .../Database/BeatmapImporterTests.cs          | 43 +++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/osu.Game.Tests/Database/BeatmapImporterTests.cs b/osu.Game.Tests/Database/BeatmapImporterTests.cs
index 38746f2567..f3ca665380 100644
--- a/osu.Game.Tests/Database/BeatmapImporterTests.cs
+++ b/osu.Game.Tests/Database/BeatmapImporterTests.cs
@@ -1018,6 +1018,49 @@ namespace osu.Game.Tests.Database
             });
         }
 
+        [Test]
+        public void TestBeatmapFilesInNestedDirectoriesAreIgnored()
+        {
+            RunTestWithRealmAsync(async (realm, storage) =>
+            {
+                var importer = new BeatmapImporter(storage, realm);
+                using var store = new RealmRulesetStore(realm, storage);
+
+                string? temp = TestResources.GetTestBeatmapForImport();
+
+                string extractedFolder = $"{temp}_extracted";
+                Directory.CreateDirectory(extractedFolder);
+
+                try
+                {
+                    using (var zip = ZipArchive.Open(temp))
+                        zip.WriteToDirectory(extractedFolder);
+
+                    var subdirectory = Directory.CreateDirectory(Path.Combine(extractedFolder, "subdir"));
+                    string modifiedCopyPath = Path.Combine(subdirectory.FullName, "duplicate.osu");
+                    File.Copy(Directory.GetFiles(extractedFolder, "*.osu").First(), modifiedCopyPath);
+
+                    using (var stream = File.OpenWrite(modifiedCopyPath))
+                    using (var textWriter = new StreamWriter(stream))
+                        await textWriter.WriteLineAsync("# adding a comment so that the hashes are different");
+
+                    using (var zip = ZipArchive.Create())
+                    {
+                        zip.AddAllFromDirectory(extractedFolder);
+                        zip.SaveTo(temp, new ZipWriterOptions(CompressionType.Deflate));
+                    }
+
+                    await importer.Import(temp);
+
+                    EnsureLoaded(realm.Realm);
+                }
+                finally
+                {
+                    Directory.Delete(extractedFolder, true);
+                }
+            });
+        }
+
         [Test]
         public void TestImportNestedStructure()
         {

From 79f7f0ecad2f5721ee84470db9f415cdcb57f417 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Dach?= <dach.bartlomiej@gmail.com>
Date: Tue, 2 Sep 2025 14:46:39 +0200
Subject: [PATCH 2/2] Ignore `.osu` files not placed at top level of beatmap
 archive on import

Closes https://github.com/ppy/osu/issues/34677.
---
 osu.Game/Beatmaps/BeatmapImporter.cs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/osu.Game/Beatmaps/BeatmapImporter.cs b/osu.Game/Beatmaps/BeatmapImporter.cs
index 28997509dc..f80c4de4ea 100644
--- a/osu.Game/Beatmaps/BeatmapImporter.cs
+++ b/osu.Game/Beatmaps/BeatmapImporter.cs
@@ -367,7 +367,11 @@ namespace osu.Game.Beatmaps
         {
             var beatmaps = new List<BeatmapInfo>();
 
-            foreach (var file in beatmapSet.Files.Where(f => f.Filename.EndsWith(".osu", StringComparison.OrdinalIgnoreCase)))
+            // stable appears to ignore `.osu` files which are not placed at the top level of the beatmap archive.
+            // the logic that achieves this is very difficult to make sense of, but appears to be located somewhere around
+            // https://github.com/peppy/osu-stable-reference/blob/67795dba3c308e7d0493b296149dcb073ca47ecb/osu!/GameplayElements/Beatmaps/BeatmapManager.cs#L207-L208
+            // only testing the `/` path separator character is sufficient as `RealmNamedFileUsage`s are normalised to use the front slash unix path separator convention
+            foreach (var file in beatmapSet.Files.Where(f => !f.Filename.Contains('/') && f.Filename.EndsWith(@".osu", StringComparison.OrdinalIgnoreCase)))
             {
                 using (var memoryStream = new MemoryStream(Files.Store.Get(file.File.GetStoragePath()))) // we need a memory stream so we can seek
                 {