From: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>
Date: Mon, 17 Mar 2025 19:46:30 +0000 (+0100)
Subject: [3.13] gh-131325: fix sendfile fallback implementation to drain data after writing... 
X-Git-Tag: v3.13.3~116
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9a43485830d20f5104951f5288f4bdf3912067d8;p=thirdparty%2FPython%2Fcpython.git

[3.13] gh-131325: fix sendfile fallback implementation to drain data after writing to transport (GH-131376) (#131377)

gh-131325: fix sendfile fallback implementation to drain data after writing to transport (GH-131376)
(cherry picked from commit 94f4d87aeb4d2d7bddcb4c3aad4f62a727ac91ee)

Co-authored-by: Kumar Aditya <kumaraditya@python.org>
---

diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py
index e19a364886ab..d6f98370fd23 100644
--- a/Lib/asyncio/base_events.py
+++ b/Lib/asyncio/base_events.py
@@ -1292,8 +1292,8 @@ class BaseEventLoop(events.AbstractEventLoop):
                 read = await self.run_in_executor(None, file.readinto, view)
                 if not read:
                     return total_sent  # EOF
-                await proto.drain()
                 transp.write(view[:read])
+                await proto.drain()
                 total_sent += read
         finally:
             if total_sent > 0 and hasattr(file, 'seek'):
diff --git a/Misc/NEWS.d/next/Library/2025-03-17-18-50-39.gh-issue-131325.wlasMF.rst b/Misc/NEWS.d/next/Library/2025-03-17-18-50-39.gh-issue-131325.wlasMF.rst
new file mode 100644
index 000000000000..6c1f64eee6ad
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-03-17-18-50-39.gh-issue-131325.wlasMF.rst
@@ -0,0 +1 @@
+Fix sendfile fallback implementation to drain data after writing to transport in :mod:`asyncio`.