fix(slots): differentiate dynamic/static compiled slots

fix #1557

packages/runtime-core/src/componentSlots.ts

@@ -11,7 +11,6 @@ import {
   isFunction,
   EMPTY_OBJ,
   ShapeFlags,
-  PatchFlags,
   extend,
   def
 } from '@vue/shared'
@@ -28,6 +27,11 @@ export type InternalSlots = {
 
 export type Slots = Readonly<InternalSlots>
 
+export const enum CompiledSlotTypes {
+  STATIC = 1,
+  DYNAMIC = 2
+}
+
 export type RawSlots = {
   [name: string]: unknown
   // manual render fn hint to skip forced children updates
@@ -40,7 +44,7 @@ export type RawSlots = {
   // object may be directly passed down to a child component in a manual
   // render function, and the optimization hint need to be on the slot object
   // itself to be preserved.
-  _?: 1
+  _?: CompiledSlotTypes
 }
 
 const isInternalKey = (key: string) => key[0] === '_' || key === '$stable'
@@ -105,10 +109,11 @@ export const initSlots = (
   children: VNodeNormalizedChildren
 ) => {
   if (instance.vnode.shapeFlag & ShapeFlags.SLOTS_CHILDREN) {
-    if ((children as RawSlots)._ === 1) {
+    const type = (children as RawSlots)._
+    if (type) {
       instance.slots = children as InternalSlots
       // make compiler marker non-enumerable
-      def(children as InternalSlots, '_', 1)
+      def(children as InternalSlots, '_', type)
     } else {
       normalizeObjectSlots(children as RawSlots, (instance.slots = {}))
     }
@@ -129,21 +134,20 @@ export const updateSlots = (
   let needDeletionCheck = true
   let deletionComparisonTarget = EMPTY_OBJ
   if (vnode.shapeFlag & ShapeFlags.SLOTS_CHILDREN) {
-    if ((children as RawSlots)._ === 1) {
+    const type = (children as RawSlots)._
+    if (type) {
       // compiled slots.
       if (__DEV__ && isHmrUpdating) {
         // Parent was HMR updated so slot content may have changed.
         // force update slots and mark instance for hmr as well
         extend(slots, children as Slots)
-      } else if (
-        // bail on dynamic slots (v-if, v-for, reference of scope variables)
-        !(vnode.patchFlag & PatchFlags.DYNAMIC_SLOTS)
-      ) {
+      } else if (type === CompiledSlotTypes.STATIC) {
         // compiled AND static.
         // no need to update, and skip stale slots removal.
         needDeletionCheck = false
       } else {
-        // compiled but dynamic - update slots, but skip normalization.
+        // compiled but dynamic (v-if/v-for on slots) - update slots, but skip
+        // normalization.
         extend(slots, children as Slots)
       }
     } else {

packages/runtime-core/src/helpers/renderSlot.ts

@@ -1,5 +1,5 @@
 import { Data } from '../component'
-import { Slots } from '../componentSlots'
+import { Slots, RawSlots, CompiledSlotTypes } from '../componentSlots'
 import {
   VNodeArrayChildren,
   openBlock,
@@ -39,7 +39,9 @@ export function renderSlot(
       Fragment,
       { key: props.key },
       slot ? slot(props) : fallback ? fallback() : [],
-      slots._ ? PatchFlags.STABLE_FRAGMENT : PatchFlags.BAIL
+      (slots as RawSlots)._ === CompiledSlotTypes.STATIC
+        ? PatchFlags.STABLE_FRAGMENT
+        : PatchFlags.BAIL
     )
   )
 }