: If your pipeline tests your code across multiple operating systems or runtime versions, embed those variables directly into your key. A cache created on a Node.js 18 Linux environment will crash if restored into a Node.js 22 Windows environment.
: This specific problem was resolved by updating from actions/cache@v3 to v4 or later, as the newer version implemented optimizations to avoid the Node.js bug. Keeping your actions updated is a fundamental best practice. It is also wise to set a segment download timeout, which prevents a stuck download from hanging your job indefinitely. The default is 10 minutes, and you can customize it by setting an environment variable named SEGMENT_DOWNLOAD_TIMEOUT_MINS .
Is this for a (like GitHub Actions, GitLab, or Jenkins)? debug-action-cache
The response shows:
to pull the most recent partial match. If this is missing, you will always start from scratch on a primary miss. Immutability : Once a cache is saved for a specific cannot be updated : If your pipeline tests your code across
If you're caching web assets or API responses within your actions, check the HTTP Cache Headers
| Problem | Likely cause | Debug check | |--------|--------------|--------------| | Cache miss every run | Key includes github.sha or github.run_id | Log the key — is it changing? | | Cache saved every run | Key too specific + no restore-keys | Add a broader restore-keys | | Cache too large (>10 GB) | Unnecessary files | List cached dir content in debug mode | | Cache not restored on pull_request | Different branch base | Use restore-keys without branch hash | Keeping your actions updated is a fundamental best practice
If you are currently debugging a specific cache failure, let me know you are using, the programming language/package manager involved, and any error messages you see in your logs. I can provide a tailored workflow snippet to fix the issue. Share public link
- name: Cache Node modules uses: actions/cache@v4 with: path: ~/.npm key: $ runner.os -node-$ hashFiles('**/package-lock.json') restore-keys: | $ runner.os -node- Use code with caution.
: Use the mxschmitt/action-tmate action to pause your workflow and SSH into the runner. This allows you to manually check if the files were actually restored to the directory you expected.
By implementing these diagnostic strategies and architectural safeguards, you can confidently resolve caching bottlenecks, stabilize flaky deployments, and keep your development loops exceptionally fast.