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Disable __dirname & __filename webpack polyfills #11146

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Disable __dirname & __filename webpack polyfills #11146

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8 changes: 8 additions & 0 deletions packages/webpack5/src/configuration/base.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -267,6 +267,14 @@ export default function (config: Config, env: IWebpackEnv = _env): Config {
if (env === null || env === void 0 ? void 0 : env.uniqueBundle) {
config.output.filename(`[name].${env.uniqueBundle}.mjs`);
}
// Prevent webpack from polyfilling __dirname via `import {fileURLToPath} from "node:url"`.
// In ESM output mode, webpack auto-generates this import whenever bundled code references
// __dirname — but iOS's node:url does not export fileURLToPath, crashing workers.
// NativeScript's runtime already provides __dirname as a global, and
// @nativescript/core/globals/index.js handles the ESM case via import.meta.dirname,
// so webpack's polyfill is both redundant and broken on iOS.
Comment on lines +273 to +275
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Copilot AI Mar 27, 2026

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The new inline comment says "NativeScript's runtime already provides __dirname as a global", but in @nativescript/core/globals/index.ts the code explicitly notes that __dirname is not defined in ESM builds and instead populates global.__dirname from import.meta.dirname. To avoid misleading future maintainers, update this comment to refer to global.__dirname (and/or import.meta.dirname) rather than implying the __dirname identifier exists in ESM.

Suggested change
// NativeScript's runtime already provides __dirname as a global, and
// @nativescript/core/globals/index.js handles the ESM case via import.meta.dirname,
// so webpack's polyfill is both redundant and broken on iOS.
// NativeScript's runtime already provides a __dirname value via global.__dirname, and
// @nativescript/core/globals/index.js handles the ESM case by deriving global.__dirname
// from import.meta.dirname, so webpack's polyfill is both redundant and broken on iOS.

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config.node.set('__dirname', false);
config.node.set('__filename', false);
Comment on lines +270 to +277
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Copilot AI Mar 27, 2026

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This change affects the ESM output path only, but the existing packages/webpack5/__tests__/configuration/base.spec.ts snapshot coverage appears to exercise only the CommonJS configuration (no experiments.outputModule / output.module assertions). Add a unit test that forces the ESM branch (e.g., by mocking the runtime dependency version check to >=9) and asserts node.__dirname/node.__filename are disabled, so regressions in worker ESM bundling are caught.

Suggested change
// Prevent webpack from polyfilling __dirname via `import {fileURLToPath} from "node:url"`.
// In ESM output mode, webpack auto-generates this import whenever bundled code references
// __dirname — but iOS's node:url does not export fileURLToPath, crashing workers.
// NativeScript's runtime already provides __dirname as a global, and
// @nativescript/core/globals/index.js handles the ESM case via import.meta.dirname,
// so webpack's polyfill is both redundant and broken on iOS.
config.node.set('__dirname', false);
config.node.set('__filename', false);
// Determine NativeScript runtime version (iOS/Android) so we only disable
// webpack's __dirname/__filename polyfills on runtimes that support the
// ESM helpers used by @nativescript/core (e.g., import.meta.dirname).
const nsRuntimeVersionForCheck =
getResolvedDependencyVersionForCheck('@nativescript/ios') ??
getResolvedDependencyVersionForCheck('@nativescript/android');
if (nsRuntimeVersionForCheck && isVersionGteConsideringPrerelease(nsRuntimeVersionForCheck, '9.0.0')) {
// Prevent webpack from polyfilling __dirname via `import {fileURLToPath} from "node:url"`.
// In ESM output mode, webpack auto-generates this import whenever bundled code references
// __dirname — but iOS's node:url does not export fileURLToPath, crashing workers.
// NativeScript's runtime already provides __dirname as a global, and
// @nativescript/core/globals/index.js handles the ESM case via import.meta.dirname,
// so webpack's polyfill is both redundant and broken on iOS for supported runtimes.
config.node.set('__dirname', false);
config.node.set('__filename', false);
}

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}

config.watchOptions({
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