Re: [ANNOUNCE] Git v2.33.0-rc2 (Build/Test Report)

[Jeff King <peff@peff.net>]

On Mon, Aug 16, 2021 at 05:55:01PM -0400, Jeff King wrote:

> So ideally we'd have some way of atomically checking our flag and then
> sleeping only if it's not set. But I don't think that exists. The
> closest we can come is using a series of smaller sleeps and checks. And
> indeed, digging in the archive shows that Max already proposed such a
> patch:
> 
>   https://lore.kernel.org/git/20190218205028.32486-1-max@max630.net/
> 
> It looks like it feel through the cracks, though. Maybe now is a good
> time to resurrect it.

And here it is for convenience. I think this is worth doing, as it
avoids occasional 60-second hangs in the test suite (and I confirmed
that with the "fail if it takes more than 5 seconds" hack I showed
earlier).

-- >8 --
From: Max Kirillov <max@max630.net>
Subject: [PATCH] t5562: chunked sleep to avoid lost SIGCHILD

If was found during stress-test run that a test may hang by 60 seconds.
It supposedly happens because SIGCHILD was received before sleep has
started.

Fix by looping by smaller chunks, checking $exited after each of them.
Then lost SIGCHILD would not cause longer delay than 1 second.

Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Max Kirillov <max@max630.net>
Signed-off-by: Jeff King <peff@peff.net>
---
 t/t5562/invoke-with-content-length.pl | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/t/t5562/invoke-with-content-length.pl b/t/t5562/invoke-with-content-length.pl
index 0943474af2..257e280e3b 100644
--- a/t/t5562/invoke-with-content-length.pl
+++ b/t/t5562/invoke-with-content-length.pl
@@ -29,7 +29,12 @@
 }
 print $out $body_data or die "Cannot write data: $!";
 
-sleep 60; # is interrupted by SIGCHLD
+my $counter = 0;
+while (not $exited and $counter < 60) {
+        sleep 1;
+        $counter = $counter + 1;
+}
+
 if (!$exited) {
         close($out);
         die "Command did not exit after reading whole body";
-- 
2.33.0.rc2.497.g375df73092