From 7527d3654760b36539de2474255c8bb9c1d976ee Mon Sep 17 00:00:00 2001
From: Saul-Mirone <Saul-Mirone@outlook.com>
Date: Sat, 1 Mar 2025 08:10:41 +0000
Subject: [PATCH] feat: prevent cycle emit in slot (#10539)

---
 .../global/src/__tests__/slot.unit.spec.ts    |  9 +++++++
 blocksuite/framework/global/src/utils/slot.ts | 24 ++++++++++++-------
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/blocksuite/framework/global/src/__tests__/slot.unit.spec.ts b/blocksuite/framework/global/src/__tests__/slot.unit.spec.ts
index 61a84358d9..7ce32c93b3 100644
--- a/blocksuite/framework/global/src/__tests__/slot.unit.spec.ts
+++ b/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);
+  });
 });
diff --git a/blocksuite/framework/global/src/utils/slot.ts b/blocksuite/framework/global/src/utils/slot.ts
index c276a3a618..beac24d955 100644
--- a/blocksuite/framework/global/src/utils/slot.ts
+++ b/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 {