fix(html): preserve content for <template> with unknown lang

src/language-html/utils.js

@@ -40,6 +40,15 @@ function hasPrettierIgnore(path) {
     return false;
   }
 
+  if (
+    node.type === "element" &&
+    node.fullName === "template" &&
+    node.attrMap.lang &&
+    node.attrMap.lang !== "html"
+  ) {
+    return true;
+  }
+
   // TODO: handle non-text children in <pre>
   if (
     isPreLikeNode(node) &&

tests/html_vue/__snapshots__/jsfmt.spec.js.snap

@@ -1140,6 +1140,36 @@ exports[`template.vue - vue-verify 2`] = `
 
 `;
 
+exports[`template-lang.vue - vue-verify 1`] = `
+<template lang="pug">
+  .test
+    #foo
+  .bla
+</template>
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+<template lang="pug">
+  .test
+    #foo
+  .bla
+</template>
+
+`;
+
+exports[`template-lang.vue - vue-verify 2`] = `
+<template lang="pug">
+  .test
+    #foo
+  .bla
+</template>
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+<template lang="pug">
+  .test
+    #foo
+  .bla
+</template>
+
+`;
+
 exports[`test.vue - vue-verify 1`] = `
 <script>
 </script>

tests/html_vue/template-lang.vue

@@ -0,0 +1,5 @@
+<template lang="pug">
+  .test
+    #foo
+  .bla
+</template>