Clean partial editor mounts and failed refreshes

packages/block-editor/src/runtime.ts

@@ -31,8 +31,20 @@ export function mountBlockEditor(root: HTMLElement, options: MountEditorOptions)
   live.style.cssText =
     "position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0";
   root.append(live);
+  const destroy = () => {
+    if (destroyed) return;
+    destroyed = true;
+    generation++;
+    try {
+      cleanups.forEach((cleanup) => cleanup());
+    } finally {
+      cleanups = [];
+      try { manager?.destroy(); } finally { live.remove(); }
+    }
+  };
   const refresh = () => {
     if (destroyed) return;
+    try {
     const currentGeneration = ++generation;
     cleanups.forEach((cleanup) => cleanup());
     cleanups = [];
@@ -145,18 +157,13 @@ export function mountBlockEditor(root: HTMLElement, options: MountEditorOptions)
         }),
       );
     }
+    } catch (error) {
+      try { destroy(); } finally { throw error; }
+    }
   };
   refresh();
   return {
     refresh,
-    destroy() {
-      if (destroyed) return;
-      destroyed = true;
-      generation++;
-      cleanups.forEach((cleanup) => cleanup());
-      cleanups = [];
-      manager?.destroy();
-      live.remove();
-    },
+    destroy,
   };
 }