From 5f17ad233f8105017683315785ce0c28d97051d5 Mon Sep 17 00:00:00 2001
From: HcySunYang <HcySunYang@outlook.com>
Date: Tue, 5 Jan 2021 22:49:03 +0800
Subject: [PATCH 1/2] feat(runtime-dom): add a warning for isCustomElement in
 runtime-only build

---
 packages/runtime-core/src/component.ts |  2 ++
 packages/runtime-core/src/index.ts     |  2 +-
 packages/runtime-dom/src/index.ts      | 23 ++++++++++++++++++++++-
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/packages/runtime-core/src/component.ts b/packages/runtime-core/src/component.ts
index 788a20b4343..cba5e604962 100644
--- a/packages/runtime-core/src/component.ts
+++ b/packages/runtime-core/src/component.ts
@@ -654,6 +654,8 @@ type CompileFunction = (
 
 let compile: CompileFunction | undefined
 
+export const isRuntimeOnly = () => !compile
+
 /**
  * For runtime-dom to register the compiler.
  * Note the exported method uses any to avoid d.ts relying on the compiler types.
diff --git a/packages/runtime-core/src/index.ts b/packages/runtime-core/src/index.ts
index 818caa597e6..a24672226db 100644
--- a/packages/runtime-core/src/index.ts
+++ b/packages/runtime-core/src/index.ts
@@ -87,7 +87,7 @@ export {
   resolveDynamicComponent
 } from './helpers/resolveAssets'
 // For integration with runtime compiler
-export { registerRuntimeCompiler } from './component'
+export { registerRuntimeCompiler, isRuntimeOnly } from './component'
 export {
   useTransitionState,
   resolveTransitionHooks,
diff --git a/packages/runtime-dom/src/index.ts b/packages/runtime-dom/src/index.ts
index 0dfe9fba003..9078f49ecf7 100644
--- a/packages/runtime-dom/src/index.ts
+++ b/packages/runtime-dom/src/index.ts
@@ -7,7 +7,8 @@ import {
   Renderer,
   HydrationRenderer,
   App,
-  RootHydrateFunction
+  RootHydrateFunction,
+  isRuntimeOnly
 } from '@vue/runtime-core'
 import { nodeOps } from './nodeOps'
 import { patchProp, forcePatchProp } from './patchProp'
@@ -55,6 +56,7 @@ export const createApp = ((...args) => {
 
   if (__DEV__) {
     injectNativeTagCheck(app)
+    injectCustomElementCheck(app)
   }
 
   const { mount } = app
@@ -83,6 +85,7 @@ export const createSSRApp = ((...args) => {
 
   if (__DEV__) {
     injectNativeTagCheck(app)
+    injectCustomElementCheck(app)
   }
 
   const { mount } = app
@@ -105,6 +108,24 @@ function injectNativeTagCheck(app: App) {
   })
 }
 
+function injectCustomElementCheck(app: App) {
+  if (isRuntimeOnly()) {
+    const value = app.config.isCustomElement
+    Object.defineProperty(app.config, 'isCustomElement', {
+      get() {
+        return value
+      },
+      set() {
+        warn(
+          `The \`isCustomElement\` config option is only respected when using the runtime compiler.` +
+            `If you are using the runtime-only build, \`isCustomElement\` must be passed to \`@vue/compiler-dom\` in the build setup instead` +
+            `- for example, via the \`compilerOptions\` option in vue-loader: https://vue-loader.vuejs.org/options.html#compileroptions.`
+        )
+      }
+    })
+  }
+}
+
 function normalizeContainer(
   container: Element | ShadowRoot | string
 ): Element | null {

From 952c5910dde0c60742fc432ec841e6b6bfc7fa93 Mon Sep 17 00:00:00 2001
From: HcySunYang <HcySunYang@outlook.com>
Date: Tue, 5 Jan 2021 22:51:28 +0800
Subject: [PATCH 2/2] chore: add comments

---
 packages/runtime-core/src/component.ts | 1 +
 packages/runtime-dom/src/index.ts      | 1 +
 2 files changed, 2 insertions(+)

diff --git a/packages/runtime-core/src/component.ts b/packages/runtime-core/src/component.ts
index cba5e604962..4053e1520c1 100644
--- a/packages/runtime-core/src/component.ts
+++ b/packages/runtime-core/src/component.ts
@@ -654,6 +654,7 @@ type CompileFunction = (
 
 let compile: CompileFunction | undefined
 
+// dev only
 export const isRuntimeOnly = () => !compile
 
 /**
diff --git a/packages/runtime-dom/src/index.ts b/packages/runtime-dom/src/index.ts
index 9078f49ecf7..1edef363f88 100644
--- a/packages/runtime-dom/src/index.ts
+++ b/packages/runtime-dom/src/index.ts
@@ -108,6 +108,7 @@ function injectNativeTagCheck(app: App) {
   })
 }
 
+// dev only
 function injectCustomElementCheck(app: App) {
   if (isRuntimeOnly()) {
     const value = app.config.isCustomElement