git

type Exec struct {
	// Dir is the working directory git commands run in. Required.
	Dir string

	// Env is the environment passed to git invocations. Empty means
	// inherit os.Environ; tests override this to set GIT_AUTHOR_*
	// for deterministic commit metadata.
	Env []string
}

type Fake struct {

	// Tags is the current set of tags. Order is irrelevant; ListTags
	// sorts on output for deterministic comparisons.
	Tags []string

	// Branch tracks the currently-checked-out branch name.
	Branch string

	// HeadSHA is what CurrentSHA returns. Tests may set this to
	// anything; the default (empty) yields a deterministic placeholder.
	HeadSHA string

	// Staged is the set of paths Add has been called with since the
	// last Commit. Each Commit appends a snapshot to Commits and
	// clears Staged.
	Staged []string

	// Removed records every Remove(paths...) call's paths.
	Removed []string

	// Commits is one entry per Commit() call: {Message, Files}.
	Commits []FakeCommit

	// Pushes records every Push call as "<remote>:<ref>[:force]".
	Pushes []string

	// PushedTags records every PushTags(remote) call.
	PushedTags []string

	// Dirty toggles IsClean's return value. By default the fake
	// reports clean; set Dirty=true to make IsClean return false.
	Dirty bool

	// FailNext, when non-nil, is returned by the next operation
	// regardless of which one. Single-shot: cleared after firing.
	// Used to test error-handling paths in higher layers.
	FailNext error

	// Dir, when non-empty, is the repository root. When set,
	// [Fake.Remove] also physically deletes the named paths from disk
	// (mirroring `git rm -f`). Tests that verify working-tree state
	// after Remove should set Dir; tests that only inspect Removed
	// can leave it empty.
	Dir string
	// contains filtered or unexported fields
}

type FakeCommit struct {
	Message string
	Files   []string

	// Deletions are the paths Remove(...) recorded for this commit.
	// Subset of Files. Tracked separately so
	// DeletedFilesInCommitsMatching can answer accurately without
	// the fake needing to know each path's add-vs-delete state.
	Deletions []string
}

type Repo interface {
	// ListTags returns every tag whose name starts with prefix. An
	// empty prefix returns all tags. Order is unspecified; callers
	// that need semver order sort with semver.Compare.
	ListTags(prefix string) ([]string, error)

	// TagsAtHead returns every tag pointing at the current HEAD
	// commit (i.e. `git tag --points-at HEAD`). Used by `monorel
	// publish` to find which tags to create provider Releases for.
	// Order is unspecified.
	TagsAtHead() ([]string, error)

	// CurrentSHA returns the SHA at HEAD.
	CurrentSHA() (string, error)

	// HeadCommitMessage returns the full commit message of HEAD
	// (subject + body, including any trailers). Used by `monorel tag`
	// to read the trailers `monorel apply` writes for downstream
	// tag creation.
	HeadCommitMessage() (string, error)

	// Add stages the named paths. No-op when paths is empty.
	Add(paths ...string) error

	// Remove unstages and deletes the named paths from the working
	// tree (i.e. `git rm`). Used to consume changeset files at
	// release time.
	Remove(paths ...string) error

	// Commit creates a commit with the given message at HEAD.
	// Returns an error if there is nothing staged.
	Commit(message string) error

	// CreateTag creates an annotated tag at HEAD. message is the
	// tag annotation; pass an empty string for a lightweight tag.
	CreateTag(name, message string) error

	// Push pushes ref to remote (e.g. Push("origin", "main") or
	// Push("origin", "monorel/release"). force=true uses --force-
	// with-lease so a stale local view doesn't clobber an upstream
	// update we don't know about.
	Push(remote, ref string, force bool) error

	// PushTags pushes every local tag to remote. monorel pushes
	// tags after the release commit lands so the order in the
	// remote's reflog is "commit, then its tags."
	PushTags(remote string) error

	// Fetch updates remote-tracking refs for ref from remote
	// (`git fetch --no-tags <remote> <ref>`). Used by the auto
	// orchestrator to refresh origin/<base-branch> before creating
	// monorel/release from it. Empty ref fetches every ref the
	// remote advertises.
	//
	// Tags are not auto-fetched (--no-tags); the auto orchestrator
	// only needs the refs that affect the release branch's plan.
	// Call ListTags or a separate fetch if you need them.
	Fetch(remote, ref string) error

	// CheckoutBranch checks out branch, creating it from the
	// current HEAD if it doesn't exist (`git checkout -B`). For
	// creating a branch from a non-HEAD start point (e.g. a remote
	// tracking ref), use [Repo.CheckoutNewBranch].
	CheckoutBranch(branch string) error

	// CheckoutNewBranch creates branch at startPoint and checks it
	// out (`git checkout -B <branch> <startPoint>`). Used by the
	// auto orchestrator to create monorel/release from the freshly
	// fetched origin/<base>.
	CheckoutNewBranch(branch, startPoint string) error

	// IsClean reports whether the working tree has no uncommitted
	// or untracked changes (i.e. `git status --porcelain` is empty).
	// Pre-release safety check: monorel refuses to run release on
	// a dirty tree.
	IsClean() (bool, error)

	// DeletedFilesInCommitsMatching returns the union of every file
	// path deleted (`--diff-filter=D`) by a commit whose subject or
	// body literally contains messageGrep. The substring match is
	// case-sensitive and does NOT use regex.
	//
	// Used by `monorel doctor` to scan past `chore(release):`
	// commits for the changeset filenames they consumed, so a
	// stale-branch + squash-merge revival can be detected.
	//
	// Order: deduplicated, sorted lexicographically. Includes paths
	// that were re-added by later commits — callers intersect
	// against the live tree to flag that case.
	DeletedFilesInCommitsMatching(messageGrep string) ([]string, error)
}