refactor: GCInterval replaces LightGC; Sync/Init drop lightGC param

gitshallow.Repo.GCInterval int:
  0 (default) = git auto gc (no explicit call)
  N = aggressive gc + prune every Nth successful pull

GC() simplified to always aggressive+prune (the only mode we use).
Sync(), Init(), Fetch() all parameter-free; GCInterval baked into Repo.

net/gitshallow/cmd/git-shallow-sync/main.go

@@ -57,7 +57,7 @@ func main() {
 
 	repo := gitshallow.New(url, absPath, defaultDepth, defaultBranch)
 
-	updated, err := repo.Sync(false)
+	updated, err := repo.Sync()
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Sync failed: %v\n", err)
 		os.Exit(1)

net/gitshallow/gitshallow.go

@@ -15,9 +15,15 @@ type Repo struct {
 	Path   string
 	Depth  int    // 0 defaults to 1, -1 for all
 	Branch string // Optional: specific branch to clone/pull
-	LightGC bool   // true = skip aggressive GC; false (default) = aggressive+prune
+
+	// GCInterval controls explicit aggressive GC after pulls.
+	//   0 (default) — no explicit gc; git runs gc.auto on its own schedule
+	//   1           — aggressive gc after every pull
+	//   N           — aggressive gc after every Nth pull
+	GCInterval int
 
 	mu        sync.Mutex
+	pullCount int
 }
 
 // New creates a new Repo instance.
@@ -35,23 +41,20 @@ func New(url, path string, depth int, branch string) *Repo {
 
 // Init clones the repo if missing, then syncs once.
 // Returns whether anything new was fetched.
-func (r *Repo) Init(lightGC bool) (bool, error) {
+func (r *Repo) Init() (bool, error) {
 	gitDir := filepath.Join(r.Path, ".git")
 	if _, err := os.Stat(gitDir); err != nil {
 		if _, err := r.Clone(); err != nil {
 			return false, err
 		}
 	}
-
-	updated, err := r.syncGit(lightGC)
-	return updated, err
+	return r.syncGit()
 }
 
 // Clone performs a shallow clone (--depth N --single-branch --no-tags).
 func (r *Repo) Clone() (bool, error) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
-
 	return r.clone()
 }
 
@@ -59,7 +62,6 @@ func (r *Repo) clone() (bool, error) {
 	if r.exists() {
 		return false, nil
 	}
-
 	if r.URL == "" {
 		return false, fmt.Errorf("repository URL is required")
 	}
@@ -93,18 +95,15 @@ func (r *Repo) exists() bool {
 // runGit executes a git command in the repo directory (or parent for clone).
 func (r *Repo) runGit(args ...string) (string, error) {
 	cmd := exec.Command("git", args...)
-
 	if _, err := os.Stat(r.Path); err == nil && r.exists() {
 		cmd.Dir = r.Path
 	} else {
 		cmd.Dir = filepath.Dir(r.Path)
 	}
-
 	output, err := cmd.CombinedOutput()
 	if err != nil {
 		return "", fmt.Errorf("git %s failed: %v\n%s", strings.Join(args, " "), err, output)
 	}
-
 	return strings.TrimSpace(string(output)), nil
 }
 
@@ -112,7 +111,6 @@ func (r *Repo) runGit(args ...string) (string, error) {
 func (r *Repo) Pull() (updated bool, err error) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
-
 	return r.pull()
 }
 
@@ -144,47 +142,36 @@ func (r *Repo) pull() (updated bool, err error) {
 	if err != nil {
 		return false, err
 	}
-
 	return oldHead != newHead, nil
 }
 
-// GC runs git gc. aggressiveGC adds --aggressive; pruneNow adds --prune=now.
-func (r *Repo) GC(aggressiveGC, pruneNow bool) error {
+// GC runs git gc --aggressive --prune=now.
+func (r *Repo) GC() error {
 	r.mu.Lock()
 	defer r.mu.Unlock()
-
-	return r.gc(aggressiveGC, pruneNow)
+	return r.gc()
 }
 
-func (r *Repo) gc(aggressiveGC, pruneNow bool) error {
+func (r *Repo) gc() error {
 	if !r.exists() {
 		return fmt.Errorf("repository does not exist at %s", r.Path)
 	}
-
-	args := []string{"gc"}
-	if aggressiveGC {
-		args = append(args, "--aggressive")
-	}
-	if pruneNow {
-		args = append(args, "--prune=now")
-	}
-
-	_, err := r.runGit(args...)
+	_, err := r.runGit("gc", "--aggressive", "--prune=now")
 	return err
 }
 
-// Sync clones if missing, pulls, and runs GC. Returns whether HEAD changed.
-// lightGC=false runs aggressive GC with --prune=now to minimize disk use.
-func (r *Repo) Sync(lightGC bool) (bool, error) {
-	return r.syncGit(lightGC)
+// Sync clones if missing, pulls, and conditionally runs GC based on GCEvery.
+// Returns whether HEAD changed.
+func (r *Repo) Sync() (bool, error) {
+	return r.syncGit()
 }
 
-// Fetch satisfies httpcache.Syncer using the Repo's LightGC setting.
+// Fetch satisfies httpcache.Syncer.
 func (r *Repo) Fetch() (bool, error) {
-	return r.syncGit(r.LightGC)
+	return r.syncGit()
 }
 
-func (r *Repo) syncGit(lightGC bool) (updated bool, err error) {
+func (r *Repo) syncGit() (updated bool, err error) {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 
@@ -199,5 +186,12 @@ func (r *Repo) syncGit(lightGC bool) (updated bool, err error) {
 		return updated, err
 	}
 
-	return true, r.gc(!lightGC, !lightGC)
+	if r.GCInterval > 0 {
+		r.pullCount++
+		if r.pullCount%r.GCInterval == 0 {
+			return true, r.gc()
+		}
+	}
+
+	return true, nil
 }

net/ipcohort/cmd/check-ip/blacklist.go

@@ -82,7 +82,7 @@ func (s *Sources) Fetch() (bool, error) {
 // For HTTP: fetches each cacher unconditionally on first run.
 func (s *Sources) Init() error {
 	if s.gitRepo != nil {
-		_, err := s.gitRepo.Init(s.gitRepo.LightGC)
+		_, err := s.gitRepo.Init()
 		return err
 	}
 	for _, syn := range s.syncs {