[PATCH] Prefer /dev/shm over /tmp in utime family tests

[Florian Weimer]

* Adhemerval Zanella:

> On 08/03/2021 14:43, Florian Weimer wrote:
>> * Adhemerval Zanella via Libc-alpha:
>> 
>>> What instead we make libsupport to use builddir as the temporary base
>>> directory instead? So all temporary files, directories, pipe, etc. would
>>> be created and tests against a user-defined directory instead of a system
>>> one.
>> 
>> It doesn't solve the issue with file system variance.  It's worse than
>> /tmp because that's more likely to be on tmpfs.  If we move the
>> directory into the build tree, everyone using XFS (that has the
>> forgetful VFS bug fixed) will end up with lots of FAILs.
>
> But it gives to the user at least a way to avoid the issue by
> specifying where to run and create all the files (even it is a loop
> device). I really think that having a buggy FS is not the best way to
> check glibc functionality, where part of tests will use a different
> system (where there is no direct requirement such as POSIX semaphore
> due its implementation).

I want to avoid artificial barriers to new contributors, and additional
complications for my own work.

To provide some context: it is difficult for me to contribute to GCC
because the Dejagnu logs are hard to interpret and contain quite a few
expected failures which are not marked as such.  We have some problems
with flaky tests, pretty much like everyone else, but the proposal here
is to add tests that fail consistently on common distributions.  Quite
frankly, I find that approach rather hostile.

Thanks,
Florian