From 0067298fe7466d56623d8183ac15b07ff67cd038 Mon Sep 17 00:00:00 2001
From: Alexander Wang <alex@terrastruct.com>
Date: Tue, 11 Feb 2025 10:33:59 -0700
Subject: [PATCH] cli: ignore watch events from backup files

---
 d2cli/watch.go | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/d2cli/watch.go b/d2cli/watch.go
index 6c240a711..f34dd0a1a 100644
--- a/d2cli/watch.go
+++ b/d2cli/watch.go
@@ -264,6 +264,12 @@ func (w *watcher) watchLoop(ctx context.Context) error {
 				return errors.New("fsnotify watcher closed")
 			}
 			w.ms.Log.Debug.Printf("received file system event %v", ev)
+
+			if isTemp, reason := isBackupFile(ev.Name); isTemp {
+				w.ms.Log.Debug.Printf("skipping event for %q: detected as %s", w.ms.HumanPath(ev.Name), reason)
+				continue
+			}
+
 			mt, err := w.ensureAddWatch(ctx, ev.Name)
 			if err != nil {
 				return err
@@ -349,6 +355,11 @@ func (w *watcher) ensureAddWatch(ctx context.Context, path string) (time.Time, e
 }
 
 func (w *watcher) addWatch(ctx context.Context, path string) (time.Time, error) {
+	if isTemp, reason := isBackupFile(path); isTemp {
+		w.ms.Log.Debug.Printf("skipping watch for %q: detected as %s", w.ms.HumanPath(path), reason)
+		return time.Time{}, nil
+	}
+
 	err := w.fw.Add(path)
 	if err != nil {
 		return time.Time{}, err
@@ -671,3 +682,41 @@ func (tfs *trackedFS) Open(name string) (fs.File, error) {
 	}
 	return f, err
 }
+
+func isBackupFile(path string) (bool, string) {
+	ext := filepath.Ext(path)
+	baseName := filepath.Base(path)
+
+	// This list is based off of https://github.com/gohugoio/hugo/blob/master/commands/hugobuilder.go#L795
+	switch {
+	case strings.HasSuffix(ext, "~"):
+		return true, "generic backup file (~)"
+	case ext == ".swp":
+		return true, "vim swap file"
+	case ext == ".swx":
+		return true, "vim swap file"
+	case ext == ".tmp":
+		return true, "generic temp file"
+	case ext == ".DS_Store":
+		return true, "OSX thumbnail"
+	case ext == ".bck":
+		return true, "Helix backup"
+	case baseName == "4913":
+		return true, "vim temp file"
+	case strings.HasPrefix(ext, ".goutputstream"):
+		return true, "GNOME temp file"
+	case strings.HasSuffix(ext, "jb_old___"):
+		return true, "IntelliJ old backup"
+	case strings.HasSuffix(ext, "jb_tmp___"):
+		return true, "IntelliJ temp file"
+	case strings.HasSuffix(ext, "jb_bak___"):
+		return true, "IntelliJ backup"
+	case strings.HasPrefix(ext, ".sb-"):
+		return true, "Byword temp file"
+	case strings.HasPrefix(baseName, ".#"):
+		return true, "Emacs lock file"
+	case strings.HasPrefix(baseName, "#"):
+		return true, "Emacs temp file"
+	}
+	return false, ""
+}