[PATCH] t4053: avoid race when killing background processes

From: Phillip Wood <phillip.wood@dunelm.org.uk>

The test 'diff --no-index reads from pipes' starts a couple of background processes that write to the pipes that are passed to "diff --no-index". If the test passes then we expect these processes to exit as all their output will have been read. However if the test fails then we want to make sure they do not hang about on the users machine and the test remembers they should be killed by calling

      test_when_finished  "! kill $!"

after each background process is created. Unfortunately there is a race where test_when_finished may run before the background process exits even when all its output has been read resulting in the kill command succeeding which causes the test to fail. Fix this by ignoring the exit status of the kill command. If the diff is successful we could instead wait for the background process to exit and check their status but that feels like it is testing the platform's printf implementation rather than git's code.

Reported-by: Jeff King <peff@peff.net>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
---
    t4053: avoid race when killing background processes
    
    Thanks to Peff for reporting this. Junio - this fixes a regression
    introduced in the current cycle. It is fairly minor though so I'm not
    sure if you want to pick it up now or wait until 2.42.0 is out.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1571%2Fphillipwood%2Fdiff-no-index-pipes-fixes-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1571/phillipwood/diff-no-index-pipes-fixes-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1571

 t/t4053-diff-no-index.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)