From 0772b5b53737669eaa459524e0eee818c0395a40 Mon Sep 17 00:00:00 2001 From: Christoph Tavan Date: Fri, 18 Sep 2020 16:35:34 +0200 Subject: [PATCH] module: fix crash on multiline named cjs imports The node process crashes when trying to parse a multiline import statement for named exports of a CommonJS module: TypeError: Cannot read property '0' of null at ModuleJob._instantiate (internal/modules/esm/module_job.js:112:77) at async ModuleJob.run (internal/modules/esm/module_job.js:137:5) at async Loader.import (internal/modules/esm/loader.js:165:24) at async rejects.name (file:///***/node/test/es-module/test-esm-cjs-named-error.mjs:56:3) at async waitForActual (assert.js:721:5) at async rejects (assert.js:830:25), The reason is that the regexp that is currently used to decorate the original error fails for multi line import statements. Unfortunately the undecorated error stack only contains the single line which causes the import to fail: file:///***/node/test/fixtures/es-modules/package-cjs-named-error/multi-line.mjs:2 comeOn, ^^^^^^ SyntaxError: The requested module './fail.cjs' does not provide an export named 'comeOn' at ModuleJob._instantiate (internal/modules/esm/module_job.js:98:21) at async ModuleJob.run (internal/modules/esm/module_job.js:141:5) at async Loader.import (internal/modules/esm/loader.js:165:24) at async rejects.name (file:///***/node/test/es-module/test-esm-cjs-named-error.mjs:56:3) at async waitForActual (assert.js:721:5) at async rejects (assert.js:830:25) Hence, for multiline import statements we cannot create an equivalent piece of code that uses default import followed by an object destructuring assignment. In any case the node process should definitely not crash. So until we have a more sophisticated way of extracting the entire problematic multiline import statement, show the code example only for single-line imports where the current regexp approach works well. Refs: https://github.com/nodejs/node/issues/35259 PR-URL: https://github.com/nodejs/node/pull/35275 Reviewed-By: Matteo Collina Reviewed-By: Anna Henningsen Reviewed-By: Myles Borins Reviewed-By: Rich Trott --- lib/internal/modules/esm/module_job.js | 21 ++++++++++++------- test/es-module/test-esm-cjs-named-error.mjs | 11 ++++++++++ .../package-cjs-named-error/fail.cjs | 3 ++- .../package-cjs-named-error/multi-line.mjs | 4 ++++ 4 files changed, 31 insertions(+), 8 deletions(-) create mode 100644 test/fixtures/es-modules/package-cjs-named-error/multi-line.mjs diff --git a/lib/internal/modules/esm/module_job.js b/lib/internal/modules/esm/module_job.js index 3f11ffc768eedb..ed681541d12723 100644 --- a/lib/internal/modules/esm/module_job.js +++ b/lib/internal/modules/esm/module_job.js @@ -107,16 +107,23 @@ class ModuleJob { await this.loader.resolve(childSpecifier, parentFileUrl); const format = await this.loader.getFormat(childFileURL); if (format === 'commonjs') { - const importStatement = splitStack[1]; - const namedImports = StringPrototypeMatch(importStatement, /{.*}/)[0]; - const destructuringAssignment = StringPrototypeReplace(namedImports, /\s+as\s+/g, ': '); e.message = `The requested module '${childSpecifier}' is expected ` + 'to be of type CommonJS, which does not support named exports. ' + 'CommonJS modules can be imported by importing the default ' + - 'export.\n' + - 'For example:\n' + - `import pkg from '${childSpecifier}';\n` + - `const ${destructuringAssignment} = pkg;`; + 'export.'; + // TODO(@ctavan): The original error stack only provides the single + // line which causes the error. For multi-line import statements we + // cannot generate an equivalent object descructuring assignment by + // just parsing the error stack. + const importStatement = splitStack[1]; + const oneLineNamedImports = StringPrototypeMatch(importStatement, /{.*}/); + if (oneLineNamedImports) { + const destructuringAssignment = + StringPrototypeReplace(oneLineNamedImports[0], /\s+as\s+/g, ': '); + e.message += '\nFor example:\n' + + `import pkg from '${childSpecifier}';\n` + + `const ${destructuringAssignment} = pkg;`; + } const newStack = StringPrototypeSplit(e.stack, '\n'); newStack[3] = `SyntaxError: ${e.message}`; e.stack = ArrayPrototypeJoin(newStack, '\n'); diff --git a/test/es-module/test-esm-cjs-named-error.mjs b/test/es-module/test-esm-cjs-named-error.mjs index d71dc959e21fb7..e9ddc67c0fbcea 100644 --- a/test/es-module/test-esm-cjs-named-error.mjs +++ b/test/es-module/test-esm-cjs-named-error.mjs @@ -10,6 +10,10 @@ const expectedRelative = 'The requested module \'./fail.cjs\' is expected to ' + 'import pkg from \'./fail.cjs\';\n' + 'const { comeOn } = pkg;'; +const expectedWithoutExample = 'The requested module \'./fail.cjs\' is ' + + 'expected to be of type CommonJS, which does not support named exports. ' + + 'CommonJS modules can be imported by importing the default export.'; + const expectedRenamed = 'The requested module \'./fail.cjs\' is expected to ' + 'be of type CommonJS, which does not support named exports. CommonJS ' + 'modules can be imported by importing the default export.\n' + @@ -52,6 +56,13 @@ rejects(async () => { message: expectedRenamed }, 'should correctly format named imports with renames'); +rejects(async () => { + await import(`${fixtureBase}/multi-line.mjs`); +}, { + name: 'SyntaxError', + message: expectedWithoutExample, +}, 'should correctly format named imports across multiple lines'); + rejects(async () => { await import(`${fixtureBase}/json-hack.mjs`); }, { diff --git a/test/fixtures/es-modules/package-cjs-named-error/fail.cjs b/test/fixtures/es-modules/package-cjs-named-error/fail.cjs index 40c512ab0e5ad2..cab82d3eb60d60 100644 --- a/test/fixtures/es-modules/package-cjs-named-error/fail.cjs +++ b/test/fixtures/es-modules/package-cjs-named-error/fail.cjs @@ -1,3 +1,4 @@ module.exports = { - comeOn: 'fhqwhgads' + comeOn: 'fhqwhgads', + everybody: 'to the limit', }; diff --git a/test/fixtures/es-modules/package-cjs-named-error/multi-line.mjs b/test/fixtures/es-modules/package-cjs-named-error/multi-line.mjs new file mode 100644 index 00000000000000..a4f80eba042576 --- /dev/null +++ b/test/fixtures/es-modules/package-cjs-named-error/multi-line.mjs @@ -0,0 +1,4 @@ +import { + comeOn, + everybody, +} from './fail.cjs';