From 062dffab26d24cb109e8e93e1612eacef9fa88c3 Mon Sep 17 00:00:00 2001
From: Teknium <127238744+teknium1@users.noreply.github.com>
Date: Wed, 7 Oct 2026 05:15:08 -0700
Subject: [PATCH] test(desktop-update): a hand-off log read racing Add-Content
 retries, not fails

test_script_killed_before_publishing_the_delegate_runs_no_update failed on
the Windows arm64 lane with PermissionError reading
logs/desktop-update-handoff.log: windows.ps1 appends each line with
Add-Content, and a poll that lands while that write holds the file is a
Windows sharing violation, not a missing line. The poll helper now
retries the read (5 s budget) instead of failing the test on it.
Same test is green on main's latest arm64 run; nothing in this PR
touches the desktop-update scripts.
---
 .../scripts/desktop_update/windows_handoff_support.py  | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tests/scripts/desktop_update/windows_handoff_support.py b/tests/scripts/desktop_update/windows_handoff_support.py
index 3b731ff584..89b73d81ae 100644
--- a/tests/scripts/desktop_update/windows_handoff_support.py
+++ b/tests/scripts/desktop_update/windows_handoff_support.py
@@ -88,8 +88,16 @@ def _op(home: Path, *args: str) -> tuple[int, str, str]:
 
 
 def _log(home: Path) -> str:
+    """The hand-off log so far. windows.ps1 appends with Add-Content, which holds the file without
+    read sharing for the length of each write: a read landing in that window is a sharing
+    violation (PermissionError), not a missing line, so it is retried."""
     path = home / 'logs/desktop-update-handoff.log'
-    return path.read_text(encoding='utf-8-sig') if path.exists() else ''
+    for _ in range(50):
+        try:
+            return path.read_text(encoding='utf-8-sig') if path.exists() else ''
+        except PermissionError:
+            time.sleep(0.1)
+    return path.read_text(encoding='utf-8-sig')
 
 
 def _custodian(home: Path, handoff: int) -> str: