Unraveling the GitHub Actions Cache Mystery: Why Your Workflow Might Ignore Your Latest Code

The Phantom Workflow: When GitHub Actions Ignores Your Updates

Imagine pushing a critical update to your GitHub Actions workflow, only to find your CI/CD pipeline stubbornly running an old, incorrect version. This frustrating scenario, where your actions seem to ignore your latest code, can halt releases and significantly impact your team's development velocity. This community insight dives into a recent discussion where a developer faced this exact challenge, uncovering a surprising root cause and practical workarounds.

Our discussion began with anthonypdawson's predicament: his GitHub Actions workflow was failing with errors like Permission denied and command not found for a script (scripts/add_release_reason.py) that no longer existed in his workflow file. Despite his local file being updated, the action run referenced an outdated version, completely blocking his releases.

Run cp README.md README.md.bak /home/runner/work/_temp/d6b35d15-baf9-409c-ba83-9ad8371aa0b2.sh: line 7: scripts/add_release_reason.py: Permission denied /home/runner/work/_temp/d6b35d15-baf9-409c-ba83-9ad8371aa0b2.sh: line 7: for: command not found Error: Process completed with exit code 127.

The immediate question for anthonypdawson, and for any dev team or delivery manager witnessing such an issue, was: "How can I make my action use the correct workflow again?" The pipeline was effectively frozen, directly impacting release schedules and team productivity.

Beyond the Obvious: Why Standard Fixes Fell Short

Community member MasteraSnackin quickly identified the core issue: GitHub Actions was likely using an older commit of the workflow file. Common solutions suggested, which usually resolve such issues, included:

• Manually triggering the workflow: Using the "Run workflow" button in the Actions tab to force a new run with the current workflow definition.
• Verifying the commit SHA: Checking the workflow file at the specific commit SHA shown in the failed run to confirm its content.
• Forcing a new push: Making a small, innocuous change to the workflow file, committing, and pushing to trigger a fresh evaluation.
• Leveraging workflow_dispatch: Ensuring that manual runs were indeed picking up the latest workflow definition.

However, for anthonypdawson, these standard troubleshooting steps proved ineffective. The workflow stubbornly clung to its outdated script reference, leading to the crucial realization that this wasn't a typical configuration error but something deeper within GitHub's infrastructure.

The Deep Dive: Unmasking the Workflow Cache Bug

The underlying problem, as both MasteraSnackin and rinas21 elaborated, points to a rare but impactful GitHub Actions internal caching bug. When a workflow is triggered, GitHub Actions is *supposed* to use the workflow file from the commit that triggered the run. However, in these specific scenarios, GitHub's internal cache can get stuck on an older version of the workflow definition, even after new commits are pushed.

This means that even if your repository's HEAD points to a commit where scripts/add_release_reason.py is long gone, the GitHub Actions runner might internally pull an older, cached version of your workflow file that still contains that problematic reference. The key diagnostic step here is to always check the "Set up job" step in your failed action run. This step explicitly shows the exact commit SHA being used for the workflow file. Comparing this SHA with your current branch HEAD will quickly reveal if GitHub is indeed running an outdated definition.

Practical Strategies for Unblocking Releases and Restoring Delivery Flow

When faced with a stale workflow, immediate action is required to maintain delivery momentum. Here are the most effective strategies:

Immediate Workarounds:

• Rename the Workflow File: This was anthonypdawson's successful, albeit unusual, fix. GitHub keys its workflow cache by filename, so creating a "new" workflow file (e.g., from release.yml to release-v2.yml) effectively bypasses the stale cache. Once the new workflow runs correctly, you can optionally revert to the original name if desired, hoping the cache has cleared in the interim.
• Delete and Re-add the Workflow File: A more drastic but often effective reset. Temporarily delete the .github/workflows/your-workflow.yml file, push the change, then re-add it in a subsequent commit and push again. This forces GitHub to re-index the workflow from scratch.
• Leverage workflow_dispatch with Caution: While useful for manual triggers, if the underlying cache is stale, even a manual trigger might pick up the old definition. Always verify the commit SHA in the "Set up job" step.

Proactive Measures & Diagnostics:

• Verify Commit SHAs Religiously: Make it a habit to check the "Set up job" step in any failed run. This provides irrefutable evidence of which workflow version GitHub is *actually* executing.
• Engage GitHub Support: If the issue persists despite workarounds, open a GitHub Support ticket with the specific run URL. They have the capability to investigate and clear server-side cache issues.
• Review Branch Protection & Merge Queues: In complex repository setups, certain branch protections or merge queue configurations could subtly influence which commit SHA is used to trigger a workflow. While less common for this specific issue, it's worth a diagnostic check.

Impact on Productivity and Performance Metrics

For dev team members, product/project managers, delivery managers, and CTOs, a stalled CI/CD pipeline due to a caching bug is more than just a technical glitch; it's a direct impediment to achieving critical performance metrics. Unforeseen blockers like this directly impact:

• Deployment Frequency: Releases are delayed or halted, reducing the number of successful deployments within a given period.
• Lead Time for Changes: The time from commit to production stretches, making the entire development process less agile and responsive.
• Change Failure Rate: While not a direct failure of the code, the inability to deploy correctly can be misconstrued as a failure in the delivery process.

Such unexpected tooling behavior can significantly skew your team's performance metrics, making it challenging to accurately assess efficiency and identify genuine bottlenecks. When engineers are blocked by infrastructure issues, it can lead to frustration and a dip in morale, potentially even impacting individual software engineer performance review examples if the root cause isn't clearly understood and communicated. It underscores the importance of resilient tooling and a clear understanding of its quirks.

Furthermore, these incidents are prime candidates for discussion in retrospective scrum templates. Analyzing why the issue occurred, how it was resolved, and what steps can prevent recurrence (or at least speed up resolution) is crucial for continuous improvement in your delivery pipeline.

Key Takeaways for Technical Leaders and Dev Teams

The GitHub Actions cache mystery highlights a critical lesson: even robust platforms can have their quirks. For technical leaders, ensuring your teams understand these nuances and have clear escalation paths is vital. For dev teams, knowing how to diagnose and work around such issues empowers them to maintain velocity.

While GitHub Actions remains an incredibly powerful tool for automation, understanding its internal mechanisms, especially caching, is paramount for maintaining high performance metrics and a smooth delivery pipeline. Don't let a phantom workflow derail your releases; be prepared to diagnose, workaround, and, when necessary, escalate to keep your CI/CD running efficiently.