esm: update containsModuleSyntax re removal of stripShebang

Author: GeoffreyBooth

lib/internal/modules/cjs/loader.js

@@ -896,11 +896,11 @@ Module.containsModuleSyntax = (source) => {
   // writing, Acorn doesn't support import() expressions as they are only Stage
   // 3; yet Node already supports them.
   const acorn = require('internal/deps/acorn/acorn/dist/acorn');
-  source = stripShebang(source);
   source = stripBOM(source);
   try {
     let prevToken, prevPrevToken;
-    for (const { type: token } of acorn.tokenizer(source)) {
+    const acornOptions = { allowHashBang: true };
+    for (const { type: token } of acorn.tokenizer(source, acornOptions)) {
       if (prevToken &&
         // By definition import or export must be followed by another token.
         (prevToken.keyword === 'import' || prevToken.keyword === 'export') &&

test/es-module/test-esm-contains-module-syntax.js

@@ -10,6 +10,7 @@ expect('esm-with-import-statement.js', 'module');
 expect('esm-with-export-statement.js', 'module');
 expect('esm-with-import-expression.js', 'module');
 expect('esm-with-indented-import-statement.js', 'module');
+expect('hashbang.js', 'module');
 
 expect('cjs-with-require.js', 'commonjs');
 expect('cjs-with-import-expression.js', 'commonjs');

test/fixtures/es-modules/detect/hashbang.js

@@ -0,0 +1,3 @@
+#!/usr/bin/env node
+import { version } from 'process';
+console.log(version);