Fix multiple issues causing database reset to fail

osu.Game/Database/DatabaseContextFactory.cs

@@ -1,6 +1,7 @@
 // Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
 // Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
+using System;
 using System.Linq;
 using System.Threading;
 using Microsoft.EntityFrameworkCore.Storage;
@@ -46,7 +47,10 @@ namespace osu.Game.Database
         public DatabaseWriteUsage GetForWrite(bool withTransaction = true)
         {
             Monitor.Enter(writeLock);
+            OsuDbContext context;
 
+            try
+            {
                 if (currentWriteTransaction == null && withTransaction)
                 {
                     // this mitigates the fact that changes on tracked entities will not be rolled back with the transaction by ensuring write operations are always executed in isolated contexts.
@@ -54,12 +58,24 @@ namespace osu.Game.Database
                     if (threadContexts.IsValueCreated)
                         recycleThreadContexts();
 
-                currentWriteTransaction = threadContexts.Value.Database.BeginTransaction();
+                    context = threadContexts.Value;
+                    currentWriteTransaction = context.Database.BeginTransaction();
+                }
+                else
+                {
+                    context = threadContexts.Value;
+                }
+            }
+            catch (Exception e)
+            {
+                // retrieval of a context could trigger a fatal error.
+                Monitor.Exit(writeLock);
+                throw;
             }
 
             Interlocked.Increment(ref currentWriteUsages);
 
-            return new DatabaseWriteUsage(threadContexts.Value, usageCompleted) { IsTransactionLeader = currentWriteTransaction != null && currentWriteUsages == 1 };
+            return new DatabaseWriteUsage(context, usageCompleted) { IsTransactionLeader = currentWriteTransaction != null && currentWriteUsages == 1 };
         }
 
         private void usageCompleted(DatabaseWriteUsage usage)
@@ -100,19 +116,18 @@ namespace osu.Game.Database
 
         private void recycleThreadContexts() => threadContexts = new ThreadLocal<OsuDbContext>(CreateContext);
 
-        protected virtual OsuDbContext CreateContext()
+        protected virtual OsuDbContext CreateContext() => new OsuDbContext(host.Storage.GetDatabaseConnectionString(database_name))
         {
-            var ctx = new OsuDbContext(host.Storage.GetDatabaseConnectionString(database_name));
+            Database = { AutoTransactionsEnabled = false }
-            ctx.Database.AutoTransactionsEnabled = false;
+        };
-
-            return ctx;
-        }
 
         public void ResetDatabase()
         {
             lock (writeLock)
             {
                 recycleThreadContexts();
+                GC.Collect();
+                GC.WaitForPendingFinalizers();
                 host.Storage.DeleteDatabase(database_name);
             }
         }

osu.Game/Database/OsuDbContext.cs

@@ -58,13 +58,22 @@ namespace osu.Game.Database
             this.connectionString = connectionString;
 
             var connection = Database.GetDbConnection();
+            try
+            {
                 connection.Open();
+
                 using (var cmd = connection.CreateCommand())
                 {
                     cmd.CommandText = "PRAGMA journal_mode=WAL;";
                     cmd.ExecuteNonQuery();
                 }
             }
+            catch (Exception e)
+            {
+                connection.Close();
+                throw;
+            }
+        }
 
         protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
         {

osu.Game/OsuGameBase.cs

@@ -211,15 +211,17 @@ namespace osu.Game
                 using (var db = contextFactory.GetForWrite(false))
                     db.Context.Migrate();
             }
-            catch (MigrationFailedException e)
+            catch (Exception e)
             {
                 Logger.Error(e.InnerException ?? e, "Migration failed! We'll be starting with a fresh database.", LoggingTarget.Database);
 
                 // if we failed, let's delete the database and start fresh.
                 // todo: we probably want a better (non-destructive) migrations/recovery process at a later point than this.
                 contextFactory.ResetDatabase();
+
                 Logger.Log("Database purged successfully.", LoggingTarget.Database, LogLevel.Important);
 
+                // only run once more, then hard bail.
                 using (var db = contextFactory.GetForWrite(false))
                     db.Context.Migrate();
             }