From 543a3ef5e45397e2a2546fc068d574b2256cc500 Mon Sep 17 00:00:00 2001
From: Cole Miller <cole@zed.dev>
Date: Thu, 12 Dec 2024 01:54:14 -0500
Subject: [PATCH] linux: Don't watch parent directory when target path already
 exists (#21854)

The Linux watcher was unconditionally watching the parent directory of
every watched path. This is needed in the case of config files that may
not exist when the watch is set up, but not in other cases. Scoping the
parent watch more narrowly cuts down on the amount of error logging from
irrelevant file change notifications being sent to Zed (in my case it
was picking up changes to a random file in `$HOME`).

Release Notes:

- N/A
---
 Cargo.lock           |  1 +
 crates/fs/Cargo.toml |  1 +
 crates/fs/src/fs.rs  | 11 +++++++----
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index d8950b856c..def04c674e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4787,6 +4787,7 @@ dependencies = [
  "git2",
  "gpui",
  "libc",
+ "log",
  "notify",
  "objc",
  "parking_lot",
diff --git a/crates/fs/Cargo.toml b/crates/fs/Cargo.toml
index 7a1cfaeaa5..fe145a6be5 100644
--- a/crates/fs/Cargo.toml
+++ b/crates/fs/Cargo.toml
@@ -21,6 +21,7 @@ git.workspace = true
 git2.workspace = true
 gpui.workspace = true
 libc.workspace = true
+log.workspace = true
 parking_lot.workspace = true
 paths.workspace = true
 rope.workspace = true
diff --git a/crates/fs/src/fs.rs b/crates/fs/src/fs.rs
index 17571de76b..0706c0e41c 100644
--- a/crates/fs/src/fs.rs
+++ b/crates/fs/src/fs.rs
@@ -695,10 +695,13 @@ impl Fs for RealFs {
         let pending_paths: Arc<Mutex<Vec<PathEvent>>> = Default::default();
         let watcher = Arc::new(linux_watcher::LinuxWatcher::new(tx, pending_paths.clone()));
 
-        watcher.add(&path).ok(); // Ignore "file doesn't exist error" and rely on parent watcher.
-        if let Some(parent) = path.parent() {
-            // watch the parent dir so we can tell when settings.json is created
-            watcher.add(parent).log_err();
+        if watcher.add(path).is_err() {
+            // If the path doesn't exist yet (e.g. settings.json), watch the parent dir to learn when it's created.
+            if let Some(parent) = path.parent() {
+                if let Err(e) = watcher.add(parent) {
+                    log::warn!("Failed to watch: {e}");
+                }
+            }
         }
 
         // Check if path is a symlink and follow the target parent