fix(plugin-federation): add .js extension to the @apollo/subgraph subpath import

[hayes]

Fixes #1661.

The bug

packages/plugin-federation/src/schema-builder.ts imports @apollo/subgraph/dist/types with no file extension. Node's ESM resolver does not guess extensions for package subpaths, and @apollo/subgraph publishes no exports map that would remap it, so importing @pothos/plugin-federation from an ESM package throws at startup on 4.4.3 through 4.5.0:

Error [ERR_MODULE_NOT_FOUND]: Cannot find module '.../@apollo/subgraph/dist/types'
imported from .../@pothos/plugin-federation/esm/schema-builder.js
Did you mean to import "@apollo/subgraph/dist/types.js"?

CJS is unaffected — require() still resolves extensions, so lib/ works on both versions.

Why it regressed

Up to 4.4.2 the ESM build appended extensions via scripts/esm-transformer.ts, which resolved bare subpaths through require.resolve and rewrote them. The TypeScript 7 migration (a32b270) replaced that step with extensions written in source and enforced by biome's useImportExtensions. That rule only covers relative imports, so the relative specifiers in this file were updated and the bare subpath on line 2 was left as it was.

The fix

One character of behavior: @apollo/subgraph/dist/types → @apollo/subgraph/dist/types.js. dist/types.js and its sibling dist/types.d.ts both exist in the published package, so CJS, ESM, and type resolution all keep working.

Other occurrences

I swept every packages/*/src tree for non-relative subpath specifiers. @apollo/subgraph/dist/types was the only one. The other subpath imports in the repo are all in examples/ and website/ (next/*, drizzle-orm/*, @apollo/server/*, fumadocs-*), which are not published and whose targets all ship exports maps.

Regression guard

Added packages/plugin-federation/tests/esm-imports.test.ts. For each package subpath imported from src, it reads the target package's manifest: if there is no exports map to remap the subpath, the specifier has to name a file that exists. This is the check biome's rule does not do.

Verification

• The reproduction from the issue fails on the pre-fix build with the exact error above, and loads cleanly after: node --input-type=module -e "await import('./esm/index.js')" → OK; node -e "require('./lib/index.js')" → OK.
• The new test fails when the extension is removed and passes with it.
• pnpm turbo run build --filter='@pothos/plugin-federation...' succeeds; the built esm/ and lib/ output both carry dist/types.js.
• pnpm vitest --run in packages/plugin-federation: 3 files, 9 tests passed, no type errors.
• pnpm biome check clean.

One note on running the suite locally: the superGraph test in tests/index.test.ts starts local HTTP servers and fails with a 405 Method Not Allowed if an HTTP proxy is set in the environment. Unsetting the proxy variables makes it pass. Unrelated to this change.

🤖 Generated with Claude Code

https://claude.ai/code/session_01L1YyNQHKx3pmp3zS9f9CMw

---

Generated by Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: d561d35

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@pothos/plugin-federation	Patch
@pothos-examples/federation	Patch
@pothos-examples/prisma-federation	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated
pothos	Ready	Preview	Sep 3, 2026 4:13pm UTC

[pkg-pr-new]

Open in StackBlitz

@pothos/core

npm i https://pkg.pr.new/@pothos/core@1662

@pothos/plugin-add-graphql

npm i https://pkg.pr.new/@pothos/plugin-add-graphql@1662

@pothos/plugin-complexity

npm i https://pkg.pr.new/@pothos/plugin-complexity@1662

@pothos/plugin-dataloader

npm i https://pkg.pr.new/@pothos/plugin-dataloader@1662

@pothos/plugin-directives

npm i https://pkg.pr.new/@pothos/plugin-directives@1662

@pothos/plugin-drizzle

npm i https://pkg.pr.new/@pothos/plugin-drizzle@1662

@pothos/plugin-errors

npm i https://pkg.pr.new/@pothos/plugin-errors@1662

@pothos/plugin-example

npm i https://pkg.pr.new/@pothos/plugin-example@1662

@pothos/plugin-federation

npm i https://pkg.pr.new/@pothos/plugin-federation@1662

@pothos/plugin-grafast

npm i https://pkg.pr.new/@pothos/plugin-grafast@1662

@pothos/plugin-mocks

npm i https://pkg.pr.new/@pothos/plugin-mocks@1662

@pothos/plugin-prisma

npm i https://pkg.pr.new/@pothos/plugin-prisma@1662

@pothos/plugin-prisma-utils

npm i https://pkg.pr.new/@pothos/plugin-prisma-utils@1662

@pothos/plugin-relay

npm i https://pkg.pr.new/@pothos/plugin-relay@1662

@pothos/plugin-scope-auth

npm i https://pkg.pr.new/@pothos/plugin-scope-auth@1662

@pothos/plugin-simple-objects

npm i https://pkg.pr.new/@pothos/plugin-simple-objects@1662

@pothos/plugin-smart-subscriptions

npm i https://pkg.pr.new/@pothos/plugin-smart-subscriptions@1662

@pothos/plugin-sub-graph

npm i https://pkg.pr.new/@pothos/plugin-sub-graph@1662

@pothos/plugin-tracing

npm i https://pkg.pr.new/@pothos/plugin-tracing@1662

@pothos/plugin-validation

npm i https://pkg.pr.new/@pothos/plugin-validation@1662

@pothos/plugin-with-input

npm i https://pkg.pr.new/@pothos/plugin-with-input@1662

@pothos/plugin-zod

npm i https://pkg.pr.new/@pothos/plugin-zod@1662

@pothos/tracing-newrelic

npm i https://pkg.pr.new/@pothos/tracing-newrelic@1662

@pothos/tracing-opentelemetry

npm i https://pkg.pr.new/@pothos/tracing-opentelemetry@1662

@pothos/tracing-sentry

npm i https://pkg.pr.new/@pothos/tracing-sentry@1662

@pothos/tracing-xray

npm i https://pkg.pr.new/@pothos/tracing-xray@1662

commit: d561d35