You have a GitHub repository that uses GitHub Actions to validate pull requests opened by...

Answer area

Correct selection

Concurrency scope

Set concurrency at the workflow level

Concurrency expression

group: ${{ github.ref }}

Workflow-level concurrency controls overlapping executions of the entire workflow. Using github.ref as the group key makes executions associated with the same ref compete for the same concurrency slot, while executions associated with different refs belong to separate groups.

For a typical pull request event, github.ref identifies the pull request merge ref. Repeated updates to that pull request therefore produce the same group value. Another pull request has a different ref and can execute independently. This provides the required coordination without imposing a single repository-wide queue on unrelated pull requests.

A constant group value would unnecessarily serialize different branches. Conversely, a group based on a unique run identifier would create a separate group for every execution and fail to prevent overlap. An actor-based group would coordinate by the initiating account rather than the pull request.

Cancellation of an already running execution is a separate policy controlled by cancel-in-progress. It is not required merely to establish the requested grouping.

Study-guide topics: concurrency boundaries, shared execution coordination, and branch-scoped orchestration. Reference: GitHub Actions—Control workflow and job concurrency .

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