Subject: bug#34519: [bug-diffutils] bug#34519: Test "colors" fails on Debian/ppc64el

From: Paul Eggert <[email-masked]>
Date: Tue, 27 Aug 2019 15:06:21 -0700

Santiago Vila wrote:
> In tests/colors there was a race condition which I tried to fix
> by adding a "sleep 1", like this:
> 
> mkfifo fifo
> printf '%1000000s-a' > a
> printf '%1000000s-b' > b
> head -c 10 < fifo > /dev/null &
> sleep 1
> diff --color=always ---presume-output-tty a b > fifo
> test $? = 141 || fail=1

Sorry, but what is the race condition, and why would adding 'sleep 1' help? The 
test should work regardless of whether 'diff' starts before 'head' does.

Are fifos broken on your system somehow?

Can you use 'strace -f' to see what syscalls are going wrong in 'head' and/or 
'diff'?