Process env build paths by ScriptedAlchemy · Pull Request #4482 · module-federation/core

ScriptedAlchemy · 2026-02-28T01:48:43Z

Description

This PR refactors internal path resolution in several packages to leverage process.env.IS_ESM_BUILD for compile-time format detection, eliminating runtime heuristics and string replacements. This ensures that tsdown can perform dead code elimination, resulting in CJS and ESM build outputs that contain only the paths and logic relevant to their respective module formats.

Specifically:

nextjs-mf: Replaced string replacement and runtime path candidates with compile-time if (process.env.IS_ESM_BUILD === 'true') blocks to hardcode .mjs or .js paths for next-fragments and runtimePlugin.
node: Updated UniversalFederationPlugin to use process.env.IS_ESM_BUILD for selecting runtimePlugin.mjs or runtimePlugin.js.
sdk: Modified node.ts to use process.env.IS_ESM_BUILD for correct require vs createRequire handling.

This change guarantees that the generated dist files for CJS and ESM builds are correctly tree-shaken and contain only the necessary code.

Related Issue

Addresses feedback and comments from PR #4460.

Types of changes

Docs change / refactoring / dependency upgrade
Bug fix (non-breaking change which fixes an issue)

Checklist

I have added tests to cover my changes.
All new and existing tests passed.
I have updated the documentation.

Co-authored-by: zackary.l.jackson <zackary.l.jackson@gmail.com>

…xport

…essor

Use tsdown with nx run-commands for migrated packages and align export and type outputs for publint. Remove legacy rollup configs and add shared migration scaffolding. Co-authored-by: Cursor <cursoragent@cursor.com>

Align package build metadata with tsdown output and type extension updates. Remove CJS fallback from ESM runtime alias resolution for consistent module format selection. Co-authored-by: Cursor <cursoragent@cursor.com>

Use .d.mts for import types so exports match emitted ESM declaration files. Co-authored-by: Cursor <cursoragent@cursor.com>

cursor · 2026-02-28T01:48:45Z

Cursor Agent can help with this pull request. Just @cursor in comments and I'll start working on changes in this branch.
_{Learn more about Cursor Agents}

changeset-bot · 2026-02-28T01:48:49Z

⚠️ No Changeset found

Latest commit: 10aa45b

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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pkg-pr-new · 2026-02-28T01:53:19Z

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@module-federation/devtools

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create-module-federation

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commit: 47512f5

ScriptedAlchemy · 2026-02-28T02:05:21Z

@codex review this pr

chatgpt-codex-connector · 2026-02-28T02:09:14Z

Codex Review: Didn't find any major issues. Keep them coming!

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Remove runtime candidate arrays and fallback probing. Select exactly one plugin file per build: plugin.js for ESM, plugin.cjs for CJS.

- rslib.config: define process.env.IS_ESM_BUILD per format (true for esm, false for cjs) - ModuleFederationPlugin: remove runtime candidate-array resolution - Use deterministic branch on IS_ESM_BUILD for runtime-tools and runtime paths - .js for ESM build, .cjs for CJS build - Keep implementationPath and require.resolve paths behavior - Preserve useful error message with specifier, paths, and original error

… tests - Remove instantiate() call after link() in ConfigTestCases.rstest.ts Node's link() already performs instantiation; calling instantiate() on a linked module throws in Node 20+ - Add status checks for cached ESM modules: return early when evaluated, skip link when already linked - Apply same instantiate() removal in asModule.js helper for consistency

ScriptedAlchemy · 2026-02-28T06:12:07Z

@codex deep research for bugs

chatgpt-codex-connector · 2026-02-28T06:19:37Z

Summary

Added a missing changeset for the PR’s publishable package behavior changes, marking @module-federation/data-prefetch, @module-federation/enhanced, @module-federation/nextjs-mf, @module-federation/node, @module-federation/rspack, and @module-federation/sdk as patch. .changeset/deep-bugs-research.mdL1-L7
Documented the release note context for the ESM/CJS build-path refactor and Node 20 ESM evaluation alignment so the original PR changes are versioned correctly on release. .changeset/deep-bugs-research.mdL10-L10
Committed on branch work with commit 7f71455 and created a follow-up PR via the make_pr tool.

Testing

✅ curl -L -s 'https://duckduckgo.com/html/?q=node+require.resolve+package+exports+subpath' | head -n 20
❌ npx nx format:check (fails in current branch baseline; Nx falls back to all files because main ref is unavailable and reports multiple repo files needing formatting)
✅ git status --short
✅ git log --oneline -3

Skipped checks (and why)

Skipped package build/test matrices from AGENTS because this follow-up only adds a changeset file (docs/release metadata), with no additional source-code behavior changes beyond the existing PR.

View task →

netlify · 2026-02-28T07:16:43Z

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github-actions · 2026-02-28T07:59:50Z

Bundle Size Report

9 package(s) changed, 32 unchanged.

Package	Total dist	Delta	ESM gzip	Delta
`modern-js-plugin`	184.8 kB	+4.0 kB (+2.2%)	1.2 kB	no change
`modern-js-plugin-v3`	176.4 kB	+4.0 kB (+2.3%)	872 B	no change
`enhanced`	1.29 MB	-1621 B (-0.1%)	744 B	no change
`data-prefetch`	118.2 kB	-683 B (-0.6%)	105 B	no change
`node`	188.4 kB	+348 B (+0.2%)	217 B	no change
`runtime-tools`	4.9 kB	+39 B (+0.8%)	95 B	no change
`nextjs-mf`	127.4 kB	-28 B (-0.0%)	160 B	no change
`inject-external-runtime-core-plugin`	5.4 kB	-26 B (-0.5%)	548 B	no change
`rspack`	58.6 kB	+8 B (+0.0%)	211 B	no change

Total dist: 6.72 MB (+6.2 kB (+0.1%))
Total ESM gzip: 79.1 kB (no change)

ScriptedAlchemy · 2026-02-28T20:22:37Z

@codex review pr

chatgpt-codex-connector

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Reviewed commit: 8ecaacd542

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chatgpt-codex-connector · 2026-02-28T20:33:38Z

packages/sdk/src/node.ts


            let requireFn: NodeRequire;
-            if (process.env['IS_ESM_BUILD'] === 'true') {
+            if (process.env.IS_ESM_BUILD === 'true') {


Use bracket access for undeclared IS_ESM_BUILD env key

packages/sdk/tsconfig.json enables noPropertyAccessFromIndexSignature, and NodeJS.ProcessEnv in this package does not declare IS_ESM_BUILD; using process.env.IS_ESM_BUILD here raises TS4111 during type/declaration builds. Since sdk builds with tsdown + dts.resolver: 'tsc', this can break the package build unless the env key is declared in ProcessEnv or accessed via process.env['IS_ESM_BUILD'].

Useful? React with 👍 / 👎.

chatgpt-codex-connector · 2026-02-28T20:33:38Z

packages/enhanced/src/lib/container/runtime/FederationRuntimePlugin.ts

+  const runtimeToolsSpec = `@module-federation/runtime-tools/dist/index${ext}`;
+  const bundlerRuntimeSpec = `@module-federation/webpack-bundler-runtime/dist/index${ext}`;
+  const runtimeSpec = `@module-federation/runtime/dist/index${ext}`;


Restore legacy runtime entry fallbacks for implementation path

This change hardcodes runtime resolution to dist/index.{js,cjs} only, removing the previous fallback set for legacy entry names and package-root resolution. In mixed-version setups (especially when implementation points to older runtime packages), require.resolve can now fail during plugin initialization, which prevents runtime alias wiring and breaks federation startup.

Useful? React with 👍 / 👎.

cursoragent and others added 30 commits February 17, 2026 20:44

feat(runtime): add shared webpack require accessor helpers

e22f492

Co-authored-by: zackary.l.jackson <zackary.l.jackson@gmail.com>

fix(utils): update remote container typing for helper import

dce6b4d

refactor(runtime-core): decouple bundler ignore helper from sdk exports

76c2216

fix(utils): keep remote container type surface unchanged

adff9b6

fix(webpack-bundler-runtime): keep internal direct webpack require usage

707aab5

refactor(utils): simplify esm remote initialization typing

aa47578

fix(webpack-bundler-runtime): use module-level webpack require accessor

14d1b76

feat(runtime-core): prefer bundler runtime import ignore helper

04ba1b4

refactor(webpack-bundler-runtime): keep ignore helper as standalone e…

7b274f1

…xport

Merge branch 'main' into cursor/bundler-runtime-require-access-725d

e3de5a3

refactor(node): migrate runtime webpack require access to bundler acc…

e0c0704

…essor

refactor: keep webpack require helpers on accessor entrypoint

f953e6e

test(webpack-bundler-runtime): avoid global webpack require mutation

4c257d8

refactor(runtime-core): source bundler-ignore helper from sdk

92b7ec0

refactor(sdk): expose bundler helper via standalone entrypoint

2e41604

refactor: route webpack runtime helpers through sdk bundler entry

49d79a6

refactor(core): migrate selected packages from rollup to tsdown

0ffd5be

Use tsdown with nx run-commands for migrated packages and align export and type outputs for publint. Remove legacy rollup configs and add shared migration scaffolding. Co-authored-by: Cursor <cursoragent@cursor.com>

fix(error-codes): align import types extension

b0ab6dc

Use .d.mts for import types so exports match emitted ESM declaration files. Co-authored-by: Cursor <cursoragent@cursor.com>

fix(utils): avoid esm namespace mutation and defer webpack require

385f226

refactor(webpack-bundler-runtime): remove accessor entrypoint leftovers

0211f52

fix(webpack-bundler-runtime): use sdk bundler webpack require

ac23c9a

fix: add regression coverage and align release metadata

c911bb6

fix(node): inline webpack require in runtime chunk strategies

ce7453a

feat(sdk): expose webpack sharing accessors in bundler entry

f2ba7eb

fix(node): use sdk bundler accessor in strategies

ca9fea3

Merge branch 'cursor/bundler-runtime-require-access-725d' into feat/tsup

bc4c4e4

fix: align tsdown unbundle and federation externals

cf22aee

fix: handle empty install args in codex setup

abd5278

fix(module-federation): clean sdk dist and drop legacy plugin probes

9c1cdd5

refactor(nextjs-mf): preselect format-specific resolve paths

743543c

ScriptedAlchemy marked this pull request as ready for review February 28, 2026 02:05

cursoragent added 6 commits February 28, 2026 03:20

fix(data-prefetch): use deterministic plugin path from IS_ESM_BUILD

b1403c2

Remove runtime candidate arrays and fallback probing. Select exactly one plugin file per build: plugin.js for ESM, plugin.cjs for CJS.

fix(rspack): use dot notation for IS_ESM_BUILD define

8dff7ba

fix(module-federation): hardcode rslib esm/cjs build branches

3df094d

fix(module-federation): restore safe IS_ESM_BUILD resolution

37efbac

fix(module-federation): harden remaining runtime plugin resolves

fd1b9fe

Base automatically changed from feat/tsup to main February 28, 2026 06:47

fix(module-federation): align enhanced runtime path selection

68ca383

ScriptedAlchemy and others added 2 commits February 27, 2026 23:25

chore: merge main into cursor/process-env-build-paths-15c0

94a598b

fix(module-federation): resolve modernjs package roots without exports

8ecaacd

chatgpt-codex-connector bot reviewed Feb 28, 2026

View reviewed changes

ScriptedAlchemy added 3 commits March 2, 2026 13:40

Merge branch 'main' into cursor/process-env-build-paths-15c0

318975a

Merge branch 'main' into cursor/process-env-build-paths-15c0

7f35e91

Merge branch 'main' into cursor/process-env-build-paths-15c0

10aa45b

zhoushaw merged commit c2a1d99 into main Mar 8, 2026
24 checks passed

zhoushaw deleted the cursor/process-env-build-paths-15c0 branch March 8, 2026 23:52

2heal1 mentioned this pull request Mar 14, 2026

Release v2.2.0 #4541

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