Revert "refactor(runtime-core): pre-refactoring of scheduling rewrite"

This reverts commit 1c8897e.

Author: johnsoncodehk

packages/reactivity/__tests__/effectScope.spec.ts

@@ -2,7 +2,6 @@ import { nextTick, watch, watchEffect } from '@vue/runtime-core'
 import {
   type ComputedRef,
   EffectScope,
-  ReactiveEffect,
   computed,
   effect,
   effectScope,
@@ -90,7 +89,7 @@ describe('reactivity/effect/scope', () => {
       })
     })
 
-    expect(getEffectsCount(scope)).toBe(1)
+    expect(getEffectsCount(scope)).toBe(2)
     expect(scope.deps?.nextDep?.dep).toBeInstanceOf(EffectScope)
 
     expect(dummy).toBe(0)
@@ -368,7 +367,7 @@ describe('reactivity/effect/scope', () => {
 function getEffectsCount(scope: EffectScope): number {
   let n = 0
   for (let dep = scope.deps; dep !== undefined; dep = dep.nextDep) {
-    if (dep.dep instanceof ReactiveEffect) {
+    if ('notify' in dep.dep) {
       n++
     }
   }

packages/reactivity/src/effect.ts

@@ -60,7 +60,7 @@ export class ReactiveEffect<T = any>
   // Subscriber
   deps: Link | undefined = undefined
   depsTail: Link | undefined = undefined
-  flags: number = SubscriberFlags.Dirty
+  flags: number = 0
   cleanups: number = 0
 
   // Dependency

packages/reactivity/src/system.ts

@@ -151,7 +151,7 @@ export function propagate(current: Link): void {
     const sub = current.sub
     const subFlags = sub.flags
 
-    let shouldNotify = false
+    let shouldNotify = 0
 
     if (
       !(
@@ -163,23 +163,23 @@ export function propagate(current: Link): void {
       )
     ) {
       sub.flags = subFlags | targetFlag
-      shouldNotify = true
+      shouldNotify = 1
     } else if (
       subFlags & SubscriberFlags.Recursed &&
       !(subFlags & SubscriberFlags.Tracking)
     ) {
       sub.flags = (subFlags & ~SubscriberFlags.Recursed) | targetFlag
-      shouldNotify = true
+      shouldNotify = 1
     } else if (
       !(subFlags & (SubscriberFlags.Dirty | SubscriberFlags.Pending)) &&
       isValidLink(current, sub)
     ) {
       sub.flags = subFlags | SubscriberFlags.Recursed | targetFlag
-      shouldNotify = !('notify' in sub)
+      shouldNotify = 2
     }
 
     if (shouldNotify) {
-      if ('notify' in sub) {
+      if (shouldNotify === 1 && 'notify' in sub) {
         notifyBuffer[notifyBufferLength++] = sub
       } else {
         const subSubs = (sub as Dependency).subs