feat: prevent cycle emit in slot (#10539)

blocksuite/framework/global/src/__tests__/slot.unit.spec.ts

@@ -43,4 +43,13 @@ describe('slot', () => {
     slot.emit();
     expect(callback).toBeCalledTimes(0);
   });
+
+  test('cycle emit', () => {
+    const slot = new Slot<number>();
+    const callback = vi.fn(v => slot.emit(v + 1));
+    slot.on(callback);
+    slot.emit(0);
+    expect(callback).toBeCalledTimes(1);
+    expect(callback).toBeCalledWith(0);
+  });
 });

blocksuite/framework/global/src/utils/slot.ts

@@ -14,16 +14,24 @@ export class Slot<T = void> implements Disposable {
   }
 
   emit(v: T) {
+    // Prevent recursive emit calls
+    if (this._emitting) {
+      return;
+    }
+
     const prevEmitting = this._emitting;
     this._emitting = true;
-    this._callbacks.forEach(f => {
-      try {
-        f(v);
-      } catch (err) {
-        console.error(err);
-      }
-    });
-    this._emitting = prevEmitting;
+    try {
+      this._callbacks.forEach(f => {
+        try {
+          f(v);
+        } catch (err) {
+          console.error(err);
+        }
+      });
+    } finally {
+      this._emitting = prevEmitting;
+    }
   }
 
   on(callback: (v: T) => unknown): Disposable {