Hello, Sergey,

thanks for the patch! See comments below.

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

The CI failure for libc 2.24 (debian 9):
https://github.com/tarantool/tarantool/actions/runs/12376159307/job/34542633454?pr=10949#step:5:13859

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

 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 also https://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

+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