Question

Your team maintains a popular JavaScript action distributed via the GitHub Marketplace. After GitHub's immutable-actions feature is enabled for your repository and you publish a new release, a downstream consumer reports that their workflow now resolves your action from the GitHub Container Registry (ghcr.io) rather than fetching the Git ref from the repository. The consumer asks what practical change immutable actions introduce for how they should reference your action. Which statement best describes the correct implication for the consumer?

Accepted Answer

Once published as an immutable action, a given released version tag cannot be moved or overwritten, so consumers can safely pin to that semantic version tag knowing its contents will never change.

Answer

Immutable actions require consumers to reference the action by its ghcr.io image digest instead of the standard owner/repo@ref syntax in the uses field.

Answer

Immutable actions eliminate the need for version pinning entirely because GitHub now guarantees all tags, including branch names, are frozen at first use.

Answer

After immutable publishing, moving major-version tags (like v1) are no longer supported at all, forcing consumers to switch exclusively to full commit SHAs.