Re: [Tarantool-patches] [PATCH luajit] test: harden skipcond for libc in LuaJIT-tests

[Sergey Kaplun via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Hi, Sergey!
Thanks for the review!
See my answers below.

On 20.12.24, Sergey Bronnikov wrote:
> Hello, Sergey,
> 
> thanks for the patch! See comments below.
> 
> 
> On 19.12.2024 12:30, Sergey Kaplun wrote:
> > The `strtod parsing` subtest in the <lib/base/tonumber_scan.lua> checks
> > the results yielded by the `strtod()` via FFI call. In glibc versions
> > before 2.28 it returns an incorrect result (NaN instead of inf) for
> > "0x3p1023" [1]. This patch hardens the skipcond for this test for a
> > smaller version of the libc installed.
> >
> > [1]:https://sourceware.org/bugzilla/show_bug.cgi?id=23279
> > ---
> >
> > Branch:https://github.com/tarantool/luajit/tree/skaplun/gh-noticket-fix-glibc-versions
> >
> > The CI failure for libc 2.23 (ubuntu 16):
> > https://github.com/tarantool/tarantool/actions/runs/12376159316/job/34542626889?pr=10949#step:5:13916
> Ubuntu 16.04 EOL and EOS are reached [1]
> > The CI failure for libc 2.24 (debian 9):
> > https://github.com/tarantool/tarantool/actions/runs/12376159307/job/34542633454?pr=10949#step:5:13859
> Debian 9 EOL is reached 4 years ago [2]
> > The CI failure for libc 2.27 (ubuntu 18):
> > https://github.com/tarantool/tarantool/actions/runs/12376159278/job/34542625496?pr=10949#step:5:11743
> > The CI pass for libc 2.31 (ubuntu 20):
> > https://github.com/tarantool/tarantool/actions/runs/12376159289/job/34542630993?pr=10949
> Ubuntu 20.04 support ends in 3 months and 2 week [1].

Yes, unfortunately we should keep (AFAICS) these runners to check the
installations for our customers.

> 
> 
> >
> >   test/LuaJIT-tests/lib/base/tonumber_scan.lua | 8 +++++---
> >   1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/test/LuaJIT-tests/lib/base/tonumber_scan.lua b/test/LuaJIT-tests/lib/base/tonumber_scan.lua
> > index ac7d68a4..800c57b0 100644
> > --- a/test/LuaJIT-tests/lib/base/tonumber_scan.lua
> > +++ b/test/LuaJIT-tests/lib/base/tonumber_scan.lua
> > @@ -186,9 +186,11 @@ do --- tonumber parsing
> >     test_conv(tonumber)
> >   end
> >   
> > --- Skip for the old libc version with the bug in the `strtod()`.
> > --- See alsohttps://sourceware.org/bugzilla/show_bug.cgi?id=16151.
> > -do --- strtod parsing -libc<2.19
> > +-- Skip for the old libc version with the bugs in the `strtod()`.
> > +-- Affected versions:
> > +-- * <2.19:https://sourceware.org/bugzilla/show_bug.cgi?id=16151.
> > +-- * <2.28:https://sourceware.org/bugzilla/show_bug.cgi?id=23279.
> 
> I propose to skip strtod test when Glibc is older than say 2.30 [3] and 
> avoid testing
> 
> with ancient Glibc versions because Glibc implementation is buggy [4] and
> 
> a there are lot of bugs in old and more or less new versions:
> 
> v2.41 [5], v2.22 [6], v2.27 [7], v2.15 [8], v2.33 [9] etc [10].
> 
> 
> I don't think we should waste our time with issues like this.
> 
> 
> 1. https://endoflife.date/ubuntu
> 
> 2. https://endoflife.date/debian
> 
> 3. https://sourceware.org/glibc/wiki/Release
> 
> 4. 
> https://github.com/tarantool/luajit/blob/cd5ab5da9b56bf560407554c0377cfa8567d4430/src/lj_strscan.c#L20-L27
> 
> 5. https://sourceware.org/bugzilla/show_bug.cgi?id=30220
> 
> 6. https://sourceware.org/bugzilla/show_bug.cgi?id=19380
> 
> 7. https://sourceware.org/bugzilla/show_bug.cgi?id=15744
> 
> 8. https://sourceware.org/bugzilla/show_bug.cgi?id=14049
> 
> 9. https://sourceware.org/bugzilla/show_bug.cgi?id=26137
> 
> 10. 
> https://sourceware.org/bugzilla/buglist.cgi?bug_status=__all__&content=strtod&no_redirect=1&order=bug_id%20DESC&product=glibc&query_format=specific

Yes, I agree that this should be the last red line for us. If the test
will fail again due to glibc, it will be easier just to drop it. For
now, I see no failures for versions 2.31 -- 2.40, and find no bugs
related to our tests that affected versions 2.28 -- 2.30, so let's skip
it for versions less than 2.28 for now.

> 
> > +do --- strtod parsing -libc<2.28
> >     test_conv(function(s)
> >       local d = ffi.C.strtod(s, e)
> >       return (e[0][0] == 0 and #s ~= 0) and d or nil

-- 
Best regards,
Sergey Kaplun