Fix skin editor freezing game if opened during active gameplay

osu.Game/Database/ImportParameters.cs

@@ -21,5 +21,11 @@ public struct ImportParameters
         /// Whether this import should use hard links rather than file copy operations if available.
         /// </summary>
         public bool PreferHardLinks { get; set; }
+
+        /// <summary>
+        /// If set to <see langword="true"/>, this import will not respect <see cref="RealmArchiveModelImporter{TModel}.PauseImports"/>.
+        /// This is useful for cases where an import <em>must</em> complete even if gameplay is in progress.
+        /// </summary>
+        public bool ImportImmediately { get; set; }
     }
 }

osu.Game/Database/RealmArchiveModelImporter.cs

@@ -261,7 +261,7 @@ await Task.WhenAll(tasks.Select(async task =>
         /// <param name="cancellationToken">An optional cancellation token.</param>
         public virtual Live<TModel>? ImportModel(TModel item, ArchiveReader? archive = null, ImportParameters parameters = default, CancellationToken cancellationToken = default) => Realm.Run(realm =>
         {
-            pauseIfNecessary(cancellationToken);
+            pauseIfNecessary(parameters, cancellationToken);
 
             TModel? existing;
 
@@ -560,9 +560,9 @@ protected virtual void UndeleteForReuse(TModel existing)
         /// <returns>Whether to perform deletion.</returns>
         protected virtual bool ShouldDeleteArchive(string path) => false;
 
-        private void pauseIfNecessary(CancellationToken cancellationToken)
+        private void pauseIfNecessary(ImportParameters importParameters, CancellationToken cancellationToken)
         {
-            if (!PauseImports)
+            if (!PauseImports || importParameters.ImportImmediately)
                 return;
 
             Logger.Log($@"{GetType().Name} is being paused.");

osu.Game/Skinning/SkinManager.cs

@@ -182,7 +182,10 @@ public bool EnsureMutableSkin()
                     Name = NamingUtils.GetNextBestName(existingSkinNames, $@"{s.Name} (modified)")
                 };
 
-                var result = skinImporter.ImportModel(skinInfo);
+                var result = skinImporter.ImportModel(skinInfo, parameters: new ImportParameters
+                {
+                    ImportImmediately = true // to avoid possible deadlocks when editing skin during gameplay.
+                });
 
                 if (result != null)
                 {