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Re: [musl] Behaviour of strverscmp(3)
From: |
Simon Josefsson |
Subject: |
Re: [musl] Behaviour of strverscmp(3) |
Date: |
Mon, 07 Nov 2022 09:51:19 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) |
Rich Felker <dalias@libc.org> writes:
> On Sun, Nov 06, 2022 at 06:18:22PM -0500, Dmitry Bogatov wrote:
>> Hello.
>>
>> While trying to building gsasl statically with musl library as part of
>> Nixpkgs distribution, I noticed that test built from tests/version.c
>> fails when built with musl library. After a bit of troubleshooting, I
>> can pinpoint the reason -- different behaviour of "strverscmp" from
>> glibc and musl.
>>
>> Example code:
>>
>> #include <string.h>
>> #include <stdio.h>
>>
>> int main()
>> {
>> int value = strverscmp("UNKNOWN", "2.2.0");
>> printf("%d\n", value);
>> return 0;
>> }
>>
>> Under glibc value "35" is printed (positive), under musl value "-1" is
>> printed (negative). Not sure what is the correct solution for the
>> issue, so I cross-post into two lists.
>>
>> For now I plan to patch-out this particular test. Thank you.
>
> It looks like we're neglecting to honor the exception case to "longer
> digit sequence is greater" when one of the sequences is degenerate (no
> digits).
Thanks for the report Dmitry (dropping cc because your email adressed
was reject by exim -- '550 restricted characters in address').
Right, I think this is a musl bug that gnulib doesn't detect and work
around. I ran into it earlier on Alpine, but must have forgotten to
report it (or I found earlier bug reports about it). Ignoring the
self-test failure is the right solution. I believe strverscmp is a
glibc-specified interface, so musl should be compatible with it, right?
I'm inclined to add this test vector to the gnulib self-test for
strverscmp, so at least we know where the problem comes from. Detecting
the issue and working around it seems like a lot of complexity (which is
a source for other bugs) and requires time and energy to support, for
what appears to be little gain, so I'm not sure it is worth it.
/Simon
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