From 5cc7160985a3418ad34980e55c6d21a31c61536d Mon Sep 17 00:00:00 2001
From: Tim Hockin <thockin@google.com>
Date: Thu, 23 Feb 2023 09:07:34 -0800
Subject: [PATCH] Clean up all old worktrees

---
 cmd/git-sync/main.go | 43 ++++++++++++++++++++++++++++++-------------
 test_e2e.sh          |  7 +++++++
 2 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/cmd/git-sync/main.go b/cmd/git-sync/main.go
index 23fe36d..c9f6871 100644
--- a/cmd/git-sync/main.go
+++ b/cmd/git-sync/main.go
@@ -1175,22 +1175,38 @@ func dirIsEmpty(dir string) (bool, error) {
 	return len(dirents) == 0, nil
 }
 
-func removeDirContents(dir string, log *logging.Logger) error {
+// removeDirContents iterated the specified dir and removes all contents,
+// except entries which are specifically excepted.
+func removeDirContents(dir string, log *logging.Logger, except ...string) error {
 	dirents, err := os.ReadDir(dir)
 	if err != nil {
 		return err
 	}
 
+	exceptMap := map[string]bool{}
+	for _, x := range except {
+		exceptMap[x] = true
+	}
+
+	// Save errors until the end.
+	var errs multiError
 	for _, fi := range dirents {
-		p := filepath.Join(dir, fi.Name())
+		name := fi.Name()
+		if exceptMap[name] {
+			continue
+		}
+		p := filepath.Join(dir, name)
 		if log != nil {
 			log.V(3).Info("removing path recursively", "path", p, "isDir", fi.IsDir())
 		}
 		if err := os.RemoveAll(p); err != nil {
-			return err
+			errs = append(errs, err)
 		}
 	}
 
+	if len(errs) != 0 {
+		return errs
+	}
 	return nil
 }
 
@@ -1261,7 +1277,7 @@ func (git *repoSync) createWorktree(ctx context.Context, hash string) (worktree,
 	}
 
 	git.log.V(0).Info("adding worktree", "path", worktree.Path(), "hash", hash)
-	_, err := git.run.Run(ctx, git.root, nil, git.cmd, "worktree", "add", "--detach", worktree.Path(), hash, "--no-checkout")
+	_, err := git.run.Run(ctx, git.root, nil, git.cmd, "worktree", "add", "--force", "--detach", worktree.Path(), hash, "--no-checkout")
 	if err != nil {
 		return "", err
 	}
@@ -1366,17 +1382,18 @@ func (git *repoSync) configureWorktree(ctx context.Context, worktree worktree) e
 	return nil
 }
 
-// cleanup removes old worktrees and runs git's garbage collection.
+// cleanup removes old worktrees and runs git's garbage collection.  The
+// specified worktree is preserved.
 func (git *repoSync) cleanup(ctx context.Context, worktree worktree) error {
 	// Save errors until the end.
 	var cleanupErrs multiError
 
-	// Clean up previous worktree.
-	// TODO: list and clean up all old worktrees
-	if worktree != "" {
-		if err := git.cleanupWorktree(ctx, worktree); err != nil {
-			cleanupErrs = append(cleanupErrs, err)
-		}
+	// Clean up previous worktree(s).
+	if err := removeDirContents(git.worktreeFor("").path(), git.log, worktree.hash()); err != nil {
+		cleanupErrs = append(cleanupErrs, err)
+	}
+	if _, err := git.run.Run(ctx, git.root, nil, git.cmd, "worktree", "prune", "--verbose"); err != nil {
+		cleanupErrs = append(cleanupErrs, err)
 	}
 
 	// Expire old refs.
@@ -1608,8 +1625,8 @@ func (git *repoSync) SyncRepo(ctx context.Context, refreshCreds func(context.Con
 	if currentHash == remoteHash {
 		currentWorktree = ""
 	}
-	if err := git.cleanup(ctx, currentWorktree); err != nil {
-		git.log.Error(err, "git cleanup failed", "oldWorktree", currentWorktree)
+	if err := git.cleanup(ctx, newWorktree); err != nil {
+		git.log.Error(err, "git cleanup failed", "newWorktree", newWorktree)
 	}
 
 	return changed, remoteHash, nil
diff --git a/test_e2e.sh b/test_e2e.sh
index f7e70fd..7837b7b 100755
--- a/test_e2e.sh
+++ b/test_e2e.sh
@@ -557,6 +557,10 @@ function e2e::worktree_cleanup() {
     SHA=$(git -C "$REPO" rev-list -n1 HEAD)
     git -C "$REPO" worktree add -q "$ROOT/.worktrees/$SHA" -b e2e --no-checkout
 
+    # add some garbage
+    mkdir -p "$ROOT/.worktrees/not_a_hash/subdir"
+    touch "$ROOT/.worktrees/not_a_directory"
+
     # resume time
     docker ps --filter label="git-sync-e2e=$RUNID" --format="{{.ID}}" \
         | while read CTR; do
@@ -567,6 +571,9 @@ function e2e::worktree_cleanup() {
     assert_file_exists "$ROOT"/link/file2
     assert_file_eq "$ROOT"/link/file2 "$FUNCNAME-ok"
     assert_metric_eq "${METRIC_GOOD_SYNC_COUNT}" 2
+    assert_file_absent "$ROOT/.worktrees/$SHA"
+    assert_file_absent "$ROOT/.worktrees/not_a_hash"
+    assert_file_absent "$ROOT/.worktrees/not_a_directory"
 }
 
 ##############################################