feat: expose the run id as a GitHub Actions step output

[moha-bekh]

After a successful upload on GitHub Actions, write the CodSpeed run id to $GITHUB_OUTPUT as run-id, so later workflow steps can read the run back instead of guessing it from the commit and branch.

All uploads of a workflow run land in the same CodSpeed run, so the id of the last upload is the run id. Failing to write the output only logs a warning.

The action will expose it as a run-id output once this is released.

Closes COD-3661

[codspeed]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 33 untouched benchmarks
⏩ 4 skipped benchmarks¹

---

_{Comparing cod-3661-expose-the-run-id-as-an-output-of-the-runner-and-the-github (d803d08) with main (080ed5f)}

Footnotes

1. 4 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[greptile-apps]

Confidence Score: 5/5

[Medium risk] Adds run ID export to GitHub Actions step outputs.

The PR appears safe to merge; no new actionable failure or outstanding previous finding was established.

Summary

The PR exports the last successful upload’s CodSpeed run ID as a GitHub Actions run-id step output. It removes the opt-in CLI setting and makes export automatic for GitHub Actions while leaving other providers with a no-op implementation.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart LR
  A[Upload completed run parts] --> B[Last upload result]
  B --> C[Export run ID]
  C -->|GitHub Actions| D[Append run-id to GITHUB_OUTPUT]
  C -->|Other providers| E[No-op]
  D -->|Write fails| F[Log warning]

Loading

_{Reviews (5) · Last reviewed commit: "feat: always export the run id on GitHub..."}

[GuillaumeLagrange]

OLGTM

[GuillaumeLagrange]

No need for three commits though, squash and merge

[GuillaumeLagrange]

lgtm once tested with the action you can merge