From 9f50a98ae6b88e45f44c37d9aea6f1a9e7e7ee1b Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Wed, 27 May 2026 09:02:05 +0000
Subject: [PATCH] =?UTF-8?q?=E2=9A=A1=20Bolt:=20Optimize=20list=20comprehen?=
 =?UTF-8?q?sions=20with=20walrus=20operator?=
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: thirdeyenation <133812267+thirdeyenation@users.noreply.github.com>
---
 .jules/bolt.md        | 4 ++++
 helpers/dirty_json.py | 2 +-
 2 files changed, 5 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..954473e674
--- /dev/null
+++ b/.jules/bolt.md
@@ -0,0 +1,4 @@
+
+## 2024-05-24 - Optimize list comprehensions with walrus operator
+ **Learning:** List comprehensions with redundant function calls (like `input_str.find(char)`) cause the function to be evaluated twice, which is an anti-pattern that slows down processing, especially for O(n) string scanning.
+ **Action:** Use the Python 3.8+ walrus operator (`:=`) to compute and bind the result once, e.g., `[idx for char in chars if (idx := input_str.find(char)) != -1]`.
diff --git a/helpers/dirty_json.py b/helpers/dirty_json.py
index 8b731bee47..ab099bf784 100644
--- a/helpers/dirty_json.py
+++ b/helpers/dirty_json.py
@@ -349,5 +349,5 @@ def _peek(self, n):
 
     def get_start_pos(self, input_str: str) -> int:
         chars = ["{", "[", '"']
-        indices = [input_str.find(char) for char in chars if input_str.find(char) != -1]
+        indices = [idx for char in chars if (idx := input_str.find(char)) != -1]
         return min(indices) if indices else 0