fix(plugin-vue): always transform cached modules in build watch mode

Author: edison1105

Diff for: packages/plugin-vue/src/index.ts

@@ -201,6 +201,8 @@ export default function vuePlugin(rawOptions: Options = {}): Plugin<Api> {
       : createFilter(customElement)
   })
 
+  let transformCachedModule = false
+
   return {
     name: 'vite:vue',
 
@@ -277,6 +279,17 @@ export default function vuePlugin(rawOptions: Options = {}): Plugin<Api> {
           !config.isProduction
         ),
       }
+      transformCachedModule =
+        config.command === 'build' &&
+        options.value.sourceMap &&
+        config.build.watch != null
+    },
+
+    shouldTransformCachedModule({ id }) {
+      if (transformCachedModule && parseVueRequest(id).query.vue) {
+        return true
+      }
+      return false
     },
 
     configureServer(server) {