Upload-artifact error in edx-platform unit tests CI

[timmc-edx]

Starting 2024-06-12 we've seen a number of instances of an error during unit-test CI runs on the master branch: an artifact with this name already exists on the workflow run. It seems to always succeed on re-run, but is affecting most or all commits as of 2024-06-13.

Notes

• Example: https://github.com/openedx/edx-platform/actions/runs/9499447454/job/26180361169
• Possibly related:
  • chore: update all github actions versions and switch to github runners #34708
  • [bug] (v4) Unable to upload to same artifact name from multiple jobs actions/upload-artifact#478

Sample instance

Run actions/upload-artifact@v4
With the provided path, there will be 1 file uploaded
Artifact 'pytest-warnings-json' (ID: 1597981853) deleted
Artifact name is valid!
Root directory input is valid!
Error: Failed to CreateArtifact: Received non-retryable error: Failed request: (409) Conflict: an artifact with this name already exists on the workflow run

The config reported for upload-artifact in that run:

   with:
    name: pytest-warnings-json
    path: test_root/log/pytest_warnings*.json
  
    overwrite: true
    if-no-files-found: warn
    compression-level: 6

[feanil]

So I took a quick look into this and it gets a bit weirder. It looks like this step downloads the warnings files to compile the full report but there is no step in any of the workflows that uploads the warnings files anymore...so...it looks like it just downloads an old one and generates the same report each time? I might be missing something but if it's causing issues and it's broken, it may make sense to just comment out this job until we can get it fully working again.