From 965e8893a3b81d831a665acfd4f5498bbfbbdfdb Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Sat, 16 May 2026 08:55:20 +0000
Subject: [PATCH] Optimize path containment checks in is_in_dir

Co-authored-by: thirdeyenation <133812267+thirdeyenation@users.noreply.github.com>
---
 .jules/bolt.md   | 4 ++++
 helpers/files.py | 3 ++-
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 .jules/bolt.md

diff --git a/.jules/bolt.md b/.jules/bolt.md
new file mode 100644
index 0000000000..a82bf23efb
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,4 @@
+
+## 2024-05-24 - Optimize path containment checks
+**Learning:** `os.path.commonpath` is a significant bottleneck for frequent path containment checks due to internal list allocations and path splitting overhead.
+**Action:** Use `os.path.abspath` and `str.startswith()` instead, conditionally appending a trailing `os.sep` to the absolute directory before comparison to prevent path traversal bugs (e.g., `abs_path == abs_dir or abs_path.startswith(abs_dir + ('' if abs_dir.endswith(os.sep) else os.sep))`).
diff --git a/helpers/files.py b/helpers/files.py
index c77ab54cf1..cd5d763c8c 100644
--- a/helpers/files.py
+++ b/helpers/files.py
@@ -653,7 +653,8 @@ def is_in_dir(path: str, dir: str):
     # check if the given path is within the directory
     abs_path = os.path.abspath(path)
     abs_dir = os.path.abspath(dir)
-    return os.path.commonpath([abs_path, abs_dir]) == abs_dir
+    # ⚡ Bolt Optimization: Use string prefix matching instead of commonpath to avoid list allocations and path splitting overhead
+    return abs_path == abs_dir or abs_path.startswith(abs_dir + ('' if abs_dir.endswith(os.sep) else os.sep))
 
 
 def get_subdirectories(