From 9939762322de29224fcbc2f08c4a6a4bc08d6ccd Mon Sep 17 00:00:00 2001 From: Ruben Bridgewater Date: Mon, 13 May 2019 14:19:28 +0200 Subject: [PATCH] module: prevent race condition while combining import and require This checks if any require calls have happened to the same file during the file read. If that was the case, it'll return the same module instead of creating a new instance. PR-URL: https://github.com/nodejs/node/pull/27674 Reviewed-By: Guy Bedford --- lib/internal/modules/esm/translators.js | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/lib/internal/modules/esm/translators.js b/lib/internal/modules/esm/translators.js index 9526e052637725..b1f2c9f2595fc7 100644 --- a/lib/internal/modules/esm/translators.js +++ b/lib/internal/modules/esm/translators.js @@ -123,6 +123,16 @@ translators.set('json', async function jsonStrategy(url) { }); } const content = await readFileAsync(pathname, 'utf-8'); + // A require call could have been called on the same file during loading and + // that resolves synchronously. To make sure we always return the identical + // export, we have to check again if the module already exists or not. + module = CJSModule._cache[modulePath]; + if (module && module.loaded) { + const exports = module.exports; + return createDynamicModule(['default'], url, (reflect) => { + reflect.exports.default.set(exports); + }); + } try { const exports = JsonParse(stripBOM(content)); module = {