From 7e6a76e587d7434f56459a6cb9a652f536dc663a Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Tue, 4 May 2021 18:20:14 -0400
Subject: [PATCH] wip: enable private vnode properties even for built-ins

---
 packages/runtime-core/src/compat/compatConfig.ts |  5 +++--
 packages/runtime-core/src/compat/renderFn.ts     | 11 ++++++++---
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/packages/runtime-core/src/compat/compatConfig.ts b/packages/runtime-core/src/compat/compatConfig.ts
index d715d9704..cbff8c785 100644
--- a/packages/runtime-core/src/compat/compatConfig.ts
+++ b/packages/runtime-core/src/compat/compatConfig.ts
@@ -566,10 +566,11 @@ export function getCompatConfigForKey(
 
 export function isCompatEnabled(
   key: DeprecationTypes,
-  instance: ComponentInternalInstance | null
+  instance: ComponentInternalInstance | null,
+  enableForBuiltIn = false
 ): boolean {
   // skip compat for built-in components
-  if (instance && instance.type.__isBuiltIn) {
+  if (!enableForBuiltIn && instance && instance.type.__isBuiltIn) {
     return false
   }
 
diff --git a/packages/runtime-core/src/compat/renderFn.ts b/packages/runtime-core/src/compat/renderFn.ts
index ba67cd366..af8e78a33 100644
--- a/packages/runtime-core/src/compat/renderFn.ts
+++ b/packages/runtime-core/src/compat/renderFn.ts
@@ -307,16 +307,21 @@ export function defineLegacyVNodeProperties(vnode: VNode) {
   if (
     isCompatEnabled(
       DeprecationTypes.RENDER_FUNCTION,
-      currentRenderingInstance
+      currentRenderingInstance,
+      true /* enable for built-ins */
     ) &&
-    isCompatEnabled(DeprecationTypes.PRIVATE_APIS, currentRenderingInstance)
+    isCompatEnabled(
+      DeprecationTypes.PRIVATE_APIS,
+      currentRenderingInstance,
+      true /* enable for built-ins */
+    )
   ) {
     const context = currentRenderingInstance
     const getInstance = () => vnode.component && vnode.component.proxy
     let componentOptions: any
     Object.defineProperties(vnode, {
       tag: { get: () => vnode.type },
-      data: { get: () => vnode.props, set: p => (vnode.props = p) },
+      data: { get: () => vnode.props || {}, set: p => (vnode.props = p) },
       elm: { get: () => vnode.el },
       componentInstance: { get: getInstance },
       child: { get: getInstance },