fix: ensure clientDir exists before writing _headers file

[Divkix]

Summary

• The closeBundle hook writes _headers to clientDir (dist/client/) without creating the directory first. Only distDir (dist/) is checked earlier in the hook.
• When build cache is invalidated (e.g., chunk graph changes), dist/client/ may not exist yet, causing an ENOENT error on writeFileSync.
• Adds fs.mkdirSync(clientDir, { recursive: true }) before the write. recursive: true is a no-op if the directory already exists, so this is safe on warm builds.

Reproduction

1. Delete dist/ entirely (simulating cache invalidation)
2. Run bun run build
3. Build fails with ENOENT: no such file or directory, open 'dist/client/_headers'

Fix

Single line addition at packages/vinext/src/index.ts — ensures the directory exists before writing.

Test plan

• Clean build (rm -rf dist && bun run build) succeeds without ENOENT
• Warm build (re-run bun run build with existing dist/) still succeeds (no-op mkdirSync)
• dist/client/_headers file is generated with correct cache headers

[Copilot]

Pull request overview

Fixes a build-time failure in the vinext:cloudflare-build closeBundle hook by ensuring the client output directory exists before writing the Cloudflare _headers file (used for immutable caching of content-hashed assets).

Changes:

• Create dist/client/ (clientDir) recursively before writing dist/client/_headers to prevent ENOENT on cold builds / cache invalidation.

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[james-elicx]

/bigbonk review

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/vinext@292

commit: d1373a6

[ask-bonk]

Clean, correct fix. The closeBundle hook guards distDir existence at line 3457 but never ensures clientDir (dist/client/) exists before writing _headers. All reads from clientDir earlier in the hook are individually guarded by existsSync, so they degrade gracefully — but the writeFileSync at line 3574 is the one unguarded write and will throw ENOENT when the directory is missing.

mkdirSync with recursive: true is the right call — idempotent on warm builds, creates the directory on cold builds. No concerns.

[ask-bonk]

Approved. The fix is correct and minimal:

• The closeBundle hook checks that distDir (dist/) exists at line 3457, but clientDir (dist/client/) is never guaranteed to exist before the writeFileSync at line 3574.
• All earlier reads from clientDir are individually guarded by existsSync, so they handle a missing directory gracefully — but the _headers write was the one unguarded operation.
• mkdirSync with recursive: true is idempotent (no-op when the directory already exists), so it's safe on both cold and warm builds.

github run