refactor(effectScope): restore parent scope after detached scope run / off

packages/reactivity/__tests__/effectScope.spec.ts

@@ -6,7 +6,8 @@ import {
   onScopeDispose,
   computed,
   ref,
-  ComputedRef
+  ComputedRef,
+  getCurrentScope
 } from '../src'
 
 describe('reactivity/effect/scope', () => {
@@ -264,3 +265,29 @@ describe('reactivity/effect/scope', () => {
     expect(watchEffectSpy).toHaveBeenCalledTimes(2)
   })
 })
+
+it('getCurrentScope() stays valid when running a detached nested EffectScope', () => {
+  const parentScope = new EffectScope()
+
+  parentScope.run(() => {
+    const currentScope = getCurrentScope()
+    expect(currentScope).toBeDefined()
+    const detachedScope = new EffectScope(true)
+    detachedScope.run(() => {})
+
+    expect(getCurrentScope()).toBe(currentScope)
+  })
+})
+
+it('getCurrentScope() stays valid when offed a detached nested EffectScope', () => {
+  const parentScope = new EffectScope()
+
+  parentScope.run(() => {
+    const currentScope = getCurrentScope()
+    expect(currentScope).toBeDefined()
+    const detachedScope = new EffectScope(true)
+    detachedScope.off()
+
+    expect(getCurrentScope()).toBe(currentScope)
+  })
+})

packages/reactivity/src/effectScope.ts

@@ -17,8 +17,8 @@ export class EffectScope {
   private index: number | undefined
 
   constructor(detached = false) {
+    this.parent = activeEffectScope
     if (!detached && activeEffectScope) {
-      this.parent = activeEffectScope
       this.index =
         (activeEffectScope.scopes || (activeEffectScope.scopes = [])).push(
           this
@@ -62,12 +62,12 @@ export class EffectScope {
         }
       }
       // nested scope, dereference from parent to avoid memory leaks
-      if (this.parent && !fromParent) {
+      if (this.index !== undefined && this.parent && !fromParent) {
         // optimized O(1) removal
         const last = this.parent.scopes!.pop()
         if (last && last !== this) {
-          this.parent.scopes![this.index!] = last
-          last.index = this.index!
+          this.parent.scopes![this.index] = last
+          last.index = this.index
         }
       }
       this.active = false