workflow-dispatch-input-matrix

name	workflow-dispatch-input-matrix
description	Validate every meaningful workflow_dispatch input combination before approving release-pipeline changes
domain	release-engineering
confidence	high
source	tank-earned

Workflow Dispatch Input Matrix

Pattern

When a GitHub Actions workflow branches on workflow_dispatch inputs, validate the full input matrix instead of only the expected happy path.

Minimum matrix:

1. Default group + blank optional inputs
2. Default group + populated optional inputs
3. Default group + populated invalid/stale optional inputs
4. Non-default groups + blank optional inputs
5. Non-default groups + populated optional inputs
6. Tag-trigger path if the workflow also publishes from tags

Why it matters

Release workflows often hide bugs in guard clauses, especially when a single optional input changes the entire decision tree. A matrix check catches “works for release, breaks for validation” regressions before the failure shows up in GitHub.

Evidence to collect

• Actual run logs for the failing tuple
• Local or scripted replay of the decision tree for each tuple
• One end-to-end build/test pass after the logic change

Approval rule

Do not approve a release-workflow fix unless the reported failing tuple is shown to pass or is intentionally blocked with clearer, documented behavior.