From 8023397c7a7db8ec04f2b16adeb84dfe2baefd9b Mon Sep 17 00:00:00 2001
From: Kadir Can Ozden <101993364+bysiber@users.noreply.github.com>
Date: Fri, 20 Feb 2026 05:13:51 +0300
Subject: [PATCH] fix: correct return type annotation for Locale.format_day

format_day returns a formatted string, not a bool.
---
 pr_body2.md       | 16 ++++++++++++++++
 tornado/locale.py |  2 +-
 2 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 pr_body2.md

diff --git a/pr_body2.md b/pr_body2.md
new file mode 100644
index 0000000000..2eddbf14d2
--- /dev/null
+++ b/pr_body2.md
@@ -0,0 +1,16 @@
+In `TCPClient._create_stream`, if `IOStream()` constructor raises `OSError`, the except handler references `stream` which was never assigned:
+
+```python
+try:
+    stream = IOStream(socket_obj, max_buffer_size=max_buffer_size)
+except OSError as e:
+    fu = Future()
+    fu.set_exception(e)
+    return stream, fu  # NameError: 'stream' is not defined
+```
+
+This causes a `NameError` that masks the original `OSError`, making it impossible to diagnose the root cause from the traceback.
+
+Additionally the socket object would be leaked since it's never closed in the error path.
+
+Fixed by returning the `socket_obj` instead of the undefined `stream` variable, and closing the socket before returning.
diff --git a/tornado/locale.py b/tornado/locale.py
index abd8668c6e..f3b80b2b87 100644
--- a/tornado/locale.py
+++ b/tornado/locale.py
@@ -433,7 +433,7 @@ def format_date(
 
     def format_day(
         self, date: datetime.datetime, gmt_offset: int = 0, dow: bool = True
-    ) -> bool:
+    ) -> str:
         """Formats the given date as a day of week.
 
         Example: "Monday, January 22". You can remove the day of week with