wip: whitespace behavior compat

packages/runtime-core/src/compat/compatConfig.ts

@@ -24,6 +24,7 @@ export const enum DeprecationTypes {
   CONFIG_KEY_CODES = 'CONFIG_KEY_CODES',
   CONFIG_PRODUCTION_TIP = 'CONFIG_PRODUCTION_TIP',
   CONFIG_IGNORED_ELEMENTS = 'CONFIG_IGNORED_ELEMENTS',
+  CONFIG_WHITESPACE = 'CONFIG_WHITESPACE',
 
   INSTANCE_SET = 'INSTANCE_SET',
   INSTANCE_DELETE = 'INSTANCE_DELETE',
@@ -162,6 +163,15 @@ const deprecationData: Record<DeprecationTypes, DeprecationData> = {
     link: `https://v3.vuejs.org/guide/migration/global-api.html#config-ignoredelements-is-now-config-iscustomelement`
   },
 
+  [DeprecationTypes.CONFIG_WHITESPACE]: {
+    // this warning is only relevant in the full build when using runtime
+    // compilation, so it's put in the runtime compatConfig list.
+    message:
+      `Vue 3 compiler's whitespace option will default to "condense" instead of ` +
+      `"preserve". To suppress this warning, provide an explicit value for ` +
+      `\`config.compilerOptions.whitespace\`.`
+  },
+
   [DeprecationTypes.INSTANCE_SET]: {
     message:
       `vm.$set() has been removed as it is no longer needed in Vue 3. ` +

packages/runtime-core/src/compat/global.ts

@@ -141,13 +141,15 @@ export function createCompatVue(
     // copy over global config mutations
     isCopyingConfig = true
     for (const key in singletonApp.config) {
+      if (key === 'isNativeTag') continue
       if (
-        key !== 'isNativeTag' &&
-        !(key === 'isCustomElement' && isRuntimeOnly())
+        isRuntimeOnly() &&
+        (key === 'isCustomElement' || key === 'compilerOptions')
       ) {
-        // @ts-ignore
-        app.config[key] = singletonApp.config[key]
+        continue
       }
+      // @ts-ignore
+      app.config[key] = singletonApp.config[key]
     }
     isCopyingConfig = false