git

type BranchRef struct {
	Name   string
	Commit string
}

type Runner interface {
	// LsRemoteTags lists the repo's tags and the commits they point to.
	LsRemoteTags(ctx context.Context, url string) ([]TagRef, error)
	// LsRemoteHeads lists the repo's branches and their head commits.
	LsRemoteHeads(ctx context.Context, url string) ([]BranchRef, error)
	// ResolveRef resolves a branch, tag, or commit ref to an immutable commit SHA.
	ResolveRef(ctx context.Context, url, ref string) (string, error)
	// FetchCommit materializes the tree at commit into dest, without a .git dir.
	FetchCommit(ctx context.Context, url, commit, dest string) error
}

type SystemRunner struct{}

type TagRef struct {
	Name   string
	Commit string
}