Allow templates to parse v8intrinsics (#11695)

* Allow templates to parse v8intrinsics

The `v8intrinsic` and `placeholders` parser plugins conflict, so enabling `placeholders` unconditionally was causing errors for V8's internal codemods. This allows them to set `syntacticPlaceholders = false` (so they'll use the legacy identifier format) and enable `v8intrinsic` by itself.

* Fix linter

* Linter

packages/babel-template/src/parse.js

@@ -27,8 +27,6 @@ export default function parseAndBuildMetadata<T>(
   code: string,
   opts: TemplateOpts,
 ): Metadata {
-  const ast = parseWithCodeFrame(code, opts.parser);
-
   const {
     placeholderWhitelist,
     placeholderPattern,
@@ -36,6 +34,8 @@ export default function parseAndBuildMetadata<T>(
     syntacticPlaceholders,
   } = opts;
 
+  const ast = parseWithCodeFrame(code, opts.parser, syntacticPlaceholders);
+
   t.removePropertiesDeep(ast, {
     preserveComments,
   });
@@ -191,13 +191,19 @@ type MetadataState = {
 function parseWithCodeFrame(
   code: string,
   parserOpts: ParserOpts,
+  syntacticPlaceholders?: boolean,
 ): BabelNodeFile {
+  const plugins = (parserOpts.plugins || []).slice();
+  if (syntacticPlaceholders !== false) {
+    plugins.push("placeholders");
+  }
+
   parserOpts = {
     allowReturnOutsideFunction: true,
     allowSuperOutsideMethod: true,
     sourceType: "module",
     ...parserOpts,
-    plugins: (parserOpts.plugins || []).concat("placeholders"),
+    plugins,
   };
 
   try {

packages/babel-template/test/index.js

@@ -294,6 +294,17 @@ describe("@babel/template", function () {
             template(`%%FOO%%`, { syntacticPlaceholders: false })({
               FOO: t.numericLiteral(1),
             });
+          }).toThrow(/Unexpected token.*/);
+        });
+
+        it("disallow manually enabled placeholders", () => {
+          expect(() => {
+            template(`%%FOO%%`, {
+              syntacticPlaceholders: false,
+              plugins: ["placeholders"],
+            })({
+              FOO: t.numericLiteral(1),
+            });
           }).toThrow(/%%.*placeholders can't be used/);
         });
 
@@ -303,6 +314,16 @@ describe("@babel/template", function () {
           });
           expect(generator(output).code).toMatchInlineSnapshot(`"1;"`);
         });
+
+        it("allows v8intrinsics", () => {
+          const output = template(`%DebugPrint(1)`, {
+            syntacticPlaceholders: false,
+            plugins: ["v8intrinsic"],
+          })();
+          expect(generator(output).code).toMatchInlineSnapshot(
+            `"%DebugPrint(1);"`,
+          );
+        });
       });
 
       describe("undefined", () => {