fix(compiler-sfc): avoid hangs when rewriting default export specifiers

packages/compiler-sfc/__tests__/rewriteDefault.spec.ts

@@ -1,4 +1,5 @@
-import { rewriteDefault } from '../src'
+import { parse } from '@babel/parser'
+import { compileScript, parse as parseSFC, rewriteDefault } from '../src'
 
 describe('compiler sfc: rewriteDefault', () => {
   test('without export default', () => {
@@ -79,6 +80,83 @@ describe('compiler sfc: rewriteDefault', () => {
     `)
   })
 
+  describe.each([
+    '/* comma, brace } */',
+    '// comma, brace }\n',
+    '// comma, brace }\r',
+    '// comma, brace }\r\n',
+    '// comma, brace }\u2028',
+    '// comma, brace }\u2029',
+  ])('trailing export specifier comment %s', comment => {
+    test.each([
+      [`a as default ${comment}`, []],
+      [`a as default ${comment}, a as b`, ['b']],
+      [`a as b, a as default ${comment}, a as c`, ['b', 'c']],
+      [`a as b, a as default ${comment}`, ['b']],
+    ] as const)('rewrite local exports: %s', (specifiers, names) => {
+      const output = rewriteDefault(
+        `const a = 1\nexport { ${specifiers} }`,
+        'script',
+      )
+      const ast = parse(output, { sourceType: 'module' })
+      const exports = ast.program.body.find(
+        node => node.type === 'ExportNamedDeclaration',
+      )!
+
+      expect(exports.specifiers.map(specifier => specifier.exported)).toEqual(
+        names.map(name => expect.objectContaining({ name })),
+      )
+      expect(output).toContain('const script = a')
+    })
+
+    test.each(['default', 'default as default', 'foo as default'])(
+      'rewrite re-exports: %s',
+      specifier => {
+        const output = rewriteDefault(
+          `export { ${specifier} ${comment}, bar } from './index.js'`,
+          'script',
+        )
+        const ast = parse(output, { sourceType: 'module' })
+        const exports = ast.program.body.find(
+          node => node.type === 'ExportNamedDeclaration',
+        )!
+
+        expect(exports.specifiers).toHaveLength(1)
+        expect(exports.specifiers[0].exported).toMatchObject({ name: 'bar' })
+        expect(exports.source).toMatchObject({ value: './index.js' })
+        expect(output).toContain('const script = __VUE_DEFAULT__')
+      },
+    )
+  })
+
+  test('rewrite an explicitly aliased default re-export', () => {
+    expect(
+      rewriteDefault(
+        `export { default as default } from './index.js'`,
+        'script',
+      ),
+    ).toBe(
+      `import { default as __VUE_DEFAULT__ } from './index.js'\n` +
+        `export {  } from './index.js'\nconst script = __VUE_DEFAULT__`,
+    )
+  })
+
+  test('compile a normal script with a trailing export specifier comment', () => {
+    const { descriptor } = parseSFC(
+      `<script>const App = {}; export { App as default /* comma, brace } */ }</script>`,
+    )
+    const compiled = compileScript(descriptor, {
+      id: 'test',
+      genDefaultAs: '_sfc_main',
+    })
+    const ast = parse(compiled.content, { sourceType: 'module' })
+
+    expect(ast.program.body[ast.program.body.length - 1]).toMatchObject({
+      type: 'VariableDeclaration',
+      declarations: [{ id: { name: '_sfc_main' }, init: { name: 'App' } }],
+    })
+  })
+
   test('export named default multiline /w comments', () => {
     expect(
       rewriteDefault(

packages/compiler-sfc/src/rewriteDefault.ts

@@ -62,7 +62,7 @@ export function rewriteDefaultAST(
               s.prepend(
                 `import { default as __VUE_DEFAULT__ } from '${node.source.value}'\n`,
               )
-              const end = specifierEnd(s, specifier.local.end!, node.end!)
+              const end = specifierEnd(s, specifier.end!, node.end!)
               s.remove(specifier.start!, end)
               s.append(`\nconst ${as} = __VUE_DEFAULT__`)
               continue
@@ -73,7 +73,7 @@ export function rewriteDefaultAST(
                   specifier.local.end!,
                 )} as __VUE_DEFAULT__ } from '${node.source.value}'\n`,
               )
-              const end = specifierEnd(s, specifier.exported.end!, node.end!)
+              const end = specifierEnd(s, specifier.end!, node.end!)
               s.remove(specifier.start!, end)
               s.append(`\nconst ${as} = __VUE_DEFAULT__`)
               continue
@@ -112,11 +112,19 @@ function specifierEnd(s: MagicString, end: number, nodeEnd: number | null) {
   while (end < nodeEnd!) {
     if (/\s/.test(s.slice(end, end + 1))) {
       end++
+    } else if (s.slice(end, end + 2) === '/*') {
+      const commentEnd = s.original.indexOf('*/', end + 2)
+      end = commentEnd === -1 ? nodeEnd! : commentEnd + 2
+    } else if (s.slice(end, end + 2) === '//') {
+      end += 2
+      while (end < nodeEnd! && !/[\r\n\u2028\u2029]/.test(s.original[end])) {
+        end++
+      }
     } else if (s.slice(end, end + 1) === ',') {
       end++
       hasCommas = true
       break
-    } else if (s.slice(end, end + 1) === '}') {
+    } else {
       break
     }
   }