Fixed recursion issue when emptying recycle bin

Co-Authored-By: Taloth <Taloth@users.noreply.github.com>

src/NzbDrone.Common.Test/DiskTests/DiskProviderFixtureBase.cs

@@ -224,6 +224,38 @@ namespace NzbDrone.Common.Test.DiskTests
             Subject.GetParentFolder(path).Should().Be(parent);
         }
 
+        [Test]
+        public void RemoveEmptySubfolders_should_remove_nested_empty_folder()
+        {
+            var mainDir = GetTempFilePath();
+            var subDir1 = Path.Combine(mainDir, "depth1");
+            var subDir2 = Path.Combine(subDir1, "depth2");
+            Directory.CreateDirectory(subDir2);
+
+            Subject.RemoveEmptySubfolders(mainDir);
+
+            Directory.Exists(mainDir).Should().Be(true);
+            Directory.Exists(subDir1).Should().Be(false);
+        }
+
+        [Test]
+        public void RemoveEmptySubfolders_should_not_remove_nested_nonempty_folder()
+        {
+            var mainDir = GetTempFilePath();
+            var subDir1 = Path.Combine(mainDir, "depth1");
+            var subDir2 = Path.Combine(subDir1, "depth2");
+            var file = Path.Combine(subDir1, "file1.txt");
+            Directory.CreateDirectory(subDir2);
+            File.WriteAllText(file, "I should not be deleted");
+
+            Subject.RemoveEmptySubfolders(mainDir);
+
+            Directory.Exists(mainDir).Should().Be(true);
+            Directory.Exists(subDir1).Should().Be(true);
+            Directory.Exists(subDir2).Should().Be(false);
+            File.Exists(file).Should().Be(true);
+        }
+
         private void DoHardLinkRename(FileShare fileShare)
         {
             var sourceDir = GetTempFilePath();

src/NzbDrone.Common/Disk/DiskProviderBase.cs

@@ -517,15 +517,21 @@ namespace NzbDrone.Common.Disk
 
         public void RemoveEmptySubfolders(string path)
         {
-            var subfolders = GetDirectories(path, SearchOption.AllDirectories);
-            var files = GetFiles(path, SearchOption.AllDirectories);
-
-            // By sorting by length descending we ensure we always delete children before parents
-            foreach (var subfolder in subfolders.OrderByDescending(x => x.Length))
+            // Depth first search for empty subdirectories
+            foreach (var subdir in Directory.EnumerateDirectories(path))
             {
-                if (files.None(f => subfolder.IsParentPath(f)))
+                RemoveEmptySubfolders(subdir);
+
+                if (Directory.EnumerateFileSystemEntries(subdir).Empty())
                 {
-                    DeleteFolder(subfolder, false);
+                    try
+                    {
+                        Directory.Delete(subdir, false);
+                    }
+                    catch (Exception ex)
+                    {
+                        Logger.Warn(ex, "Failed to remove empty directory {0}", subdir);
+                    }
                 }
             }
         }