Re: [PATCH] libstdc++: testsuite: fs rename to self may fail

[Alexandre Oliva <oliva@adacore.com>]

Hello, Sebastian,

On Jun 22, 2022, Sebastian Huber <sebastian.huber@embedded-brains.de> wrote:

> On 22/06/2022 08:24, Alexandre Oliva via Libstdc++ wrote:
>> rtems6's rename() implementation errors with EEXIST when the rename-to
>> filename exists, even when renaming a file to itself or when renaming
>> a nonexisting file.  Adjust expectations.
>> 
>> Regstrapped on x86_64-linux-gnu, also tested with a cross to
>> aarch64-rtems6.  Ok to install?
>> 
>> PS:https://devel.rtems.org/ticket/2169  doesn't seem to suggest plans to
>> change behavior so as to comply with POSIX.

> I would not adjust the test case to cope with systems which are not in
> line with POSIX.

My understanding is that the libstdc++ testsuite is not meant to test
for POSIX conformance, but for conformance with the C++ language
standards.

C++ inherits rename from C, and C says the behavior is implementation
defined if the new name already exists.

RTEMS is thus comformant with the requirements from C (and thus C++),
and it is therefore reasonable for libstdc++'s testsuite to accept
RTEMS' behavior as such.


That said, because libstdc++ tests are all-or-nothing, perhaps it would
make sense to have a separate test for strict POSIX conformance in
rename, XFAILed on RTEMS targets.  How about that?

-- 
Alexandre Oliva, happy hacker                https://FSFLA.org/blogs/lxo/
   Free Software Activist                       GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
but very few check the facts.  Ask me about <https://stallmansupport.org>