The 'workflow_run' trigger has a 'branches:' filter. What does it filter?
Select an answer to reveal the explanation.
Short Explanation and Infographic
workflow_run's branches filter narrows which branch the upstream workflow was running on — not the current workflow's branch.
Full explanation below image
![Educational infographic 1024x768 showing workflowrun branches filter. Upstream Workflow A runs on: push to main (branches: main triggers downstream), push to feature-branch (no trigger, filtered out). Downstream Workflow B: workflowrun: workflows: [CI], branches: [main]. Arrow showing only main-branch completion triggers downstream. Labels distinguishing 'triggering workflow's branch' vs 'current workflow's branch'.](/media/github/gh-200/GH-200-q127-infographic.webp)
Full Explanation
The 'workflow_run' trigger's 'branches:' and 'branches-ignore:' filters specify which branches the TRIGGERING (upstream) workflow must have been running on for the downstream workflow to fire. For example, 'branches: [main]' means 'only trigger when the named workflow completed a run that was on the main branch.' This is different from other triggers where 'branches:' filters the branch being pushed or PR'd. The downstream 'workflow_run' workflow always runs on the default branch. This makes it useful for: deploy on main builds only, skip PR build artifacts for deployment.