Question

A developer defines the following matrix strategy in a workflow job named `test`:

```yaml
jobs:
  test:
    strategy:
      matrix:
        os: [ubuntu-latest, windows-latest]
        node: [16, 18, 20]
        include:
          - os: ubuntu-latest
            node: 20
            experimental: true
    runs-on: ${{ matrix.os }}
```

In the Actions UI checks list, one variant appears as `test (ubuntu-latest, 20, true)` and shows a red X, while `test (ubuntu-latest, 20)` is not listed separately. What does this tell you about the failed variant?

Accepted Answer

The `include` entry merged its `experimental: true` value into the existing ubuntu-latest/node-20 combination, so that single job carries all three axis values and is the one that failed.

Answer

The `include` entry created an additional 7th job separate from the base 6, and both the merged job and the original ubuntu-latest/node-20 job failed.

Answer

The `experimental: true` flag caused GitHub to run the ubuntu-latest/node-20 job in a special sandbox that is expected to fail and can be ignored.

Answer

The variant name shows `true` because `fail-fast` was triggered, marking the ubuntu-latest/node-20 job as experimental after the first failure.