fix(reactivity): effect should handle self dependency mutations

packages/reactivity/__tests__/effect.spec.ts

@@ -6,7 +6,8 @@ import {
   TrackOpTypes,
   TriggerOpTypes,
   DebuggerEvent,
-  markNonReactive
+  markNonReactive,
+  ref
 } from '../src/index'
 import { ITERATE_KEY } from '../src/effect'
 
@@ -735,4 +736,14 @@ describe('reactivity/effect', () => {
     obj.foo = NaN
     expect(fnSpy).toHaveBeenCalledTimes(1)
   })
+
+  it('should handle self dependency mutations', () => {
+    const count = ref(0)
+    effect(() => {
+      count.value++
+    })
+    expect(count.value).toBe(1)
+    count.value = 10
+    expect(count.value).toBe(11)
+  })
 })

packages/reactivity/src/effect.ts

@@ -210,11 +210,17 @@ function addRunners(
 ) {
   if (effectsToAdd !== void 0) {
     effectsToAdd.forEach(effect => {
+      if (effect !== activeEffect) {
         if (effect.options.computed) {
           computedRunners.add(effect)
         } else {
           effects.add(effect)
         }
+      } else {
+        // the effect mutated its own dependency during its execution.
+        // this can be caused by operations like foo.value++
+        // do not trigger or we end in an infinite loop
+      }
     })
   }
 }