Re: Infinite loop generating QEMU docs after upgrade to Perl 5.28.0

[Niko Tyni]

Hi, I believe I've found the issue with makeinfo on Perl 5.28.

Aside from the trivial unescaped left brace things, there's a change
in locale handling that can indeed cause a busy loop for some inputs
under non-UTF8 locales.

I've been able to reduce the necessary input to just two lines:

  @documentencoding UTF-8
  @indicateurl{foo}

The busy loop happens in xspara__add_next()
(Texinfo::Convert::XSParagraph) when mbrtowc(3) returns -1, indicating
an invalid multibyte sequence even though it is valid UTF-8.

Perl 5.28 introduced thread-safe locales, where setlocale() only affects
the locale of the current thread. Apparently external code like mbrtowc(3)
isn't aware of this thread specific locale without special handling.

I'm attaching a patch that fixes this for me, and another one for the
necessary left brace escaping. Even with this, I suppose xspara.c could
use some mbrtowc(3) return value checks.

Some pointers:

 
https://metacpan.org/pod/distribution/perl/pod/perldelta.pod#Locales-are-now-thread-safe-on-systems-that-support-them
 
https://metacpan.org/pod/distribution/perl/dist/ExtUtils-ParseXS/lib/perlxs.pod#CAVEATS
 https://perl5.git.perl.org/perl.git/commitdiff/e9bc6d6b34a
 https://perl5.git.perl.org/perl.git/commitdiff/58e641fba50

Hope this helps,
-- 
Niko Tyni   address@hidden

0001-Update-locale-handling-for-Perl-5.28.patch
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perl-528-fixes
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