Question

You are authoring a composite action for your organization. The action.yml defines a `runs.using: composite` block with several `run:` steps that execute build commands. When a teammate consumes the action in a workflow, the run fails immediately with the error: "Error: Required property is missing: shell". What must you change in the action.yml to resolve this?

Accepted Answer

Add a `shell:` key (for example `shell: bash`) to each `run:` step in the composite action's steps.

Answer

Change `runs.using` from `composite` to `node20`, since `run:` steps are only valid in JavaScript actions.

Answer

Add a top-level `defaults.run.shell` key at the root of action.yml to apply a shell to all steps.

Answer

Move the `shell:` key into the workflow file that calls the action, under the `uses:` step.