Bun: Internal error 'directory mismatch for directory' in v1 action on GitHub-hosted runners

[sjawhar]

Summary

Every invocation of anthropics/claude-code-action@v1 from our repo's review workflow fails with a Bun internal error during action setup:

Internal error: directory mismatch for directory "/home/runner/work/_actions/anthropics/claude-code-action/v1/tsconfig.json", fd 4

The error comes from Bun (the runtime the action uses); no user code runs. It reproduces on every PR in our repo.

Reproduction

A reproducing run from PR #10526 in our repo (trajectory-labs-pbc/agent-c):
https://github.com/trajectory-labs-pbc/agent-c/actions/runs/24585295927/job/71893230564

The failure occurs in the review job, during action setup, before any user inputs are consumed.

Impact

review jobs fail on every PR, blocking green CI for repos that require all checks to pass.

Environment

• Runner: ubuntu-latest (GitHub-hosted)
• Action ref: anthropics/claude-code-action@v1
• Our repo: public, standard PR-triggered workflow

Ask

• Pin Bun to a known-good version inside the action, or
• Surface a more actionable error if this is a repo- or path-specific issue, or
• Advise on a workaround we can apply from the caller side.

Happy to provide more logs on request.