Hello, Em terça-feira, 27 de agosto de 2019, às 19:06:21 -03, Paul Eggert escreveu: > 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'?
I still see this problem on powerpc64le-linux with version 3.8. There was a great analysis of the problem made by Frédéric Bonnard (whom I took the liberty of copying on this message. I hope it’s ok), and also a tentative fix by him which would need to be assessed by someone more knowledgeable of the diffutils code: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=922552#19 In short: it’s not a problem in the test. It’s a bug in the signal handling code that was added to support the ‘--color’ option. For some reason, it’s particularly easy to hit on powerpc64le-linux. With Frédéric’s patch I can’t hit it anymore. -- Thanks, Thiago
