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

[Melvin Mawhin]

Hi,

This patch works very well.

Kr

Mel

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From: Niko Tyni <address@hidden>
Sent: Saturday, June 30, 2018 8:27 PM
To: address@hidden
Cc: Gavin Smith; Melvin Mawhin
Subject: Re: Infinite loop generating QEMU docs after upgrade to Perl 5.28.0

 

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://nam04.safelinks.protection.outlook.com/?url="">
 https://nam04.safelinks.protection.outlook.com/?url="">
 https://nam04.safelinks.protection.outlook.com/?url="">
 https://nam04.safelinks.protection.outlook.com/?url="">

Hope this helps,
--
Niko Tyni   address@hidden