[Po4a-Devel] Re: Complex regular subexpression recursion limit (32766) exceeded

On Jul 19, 2021, at 0:39, Martin Quinson <martin.quinson(a)ens-rennes.fr&gt; wrote: Hello Jean-Christophe, this is https://github.com/mquinson/po4a/issues/37 that was "fixed" in the past by adding a new line to org.texi. I still fail to understand how to fix it properly, and a patch would be more than welcome here. Thanks, Mt ----- Le 18 Juil 21, à 17:11, Jean-Christophe Helary lists(a)traduction-libre.org a écrit : > When trying to convert org.texi to PO I get the following error: > > Complex regular subexpression recursion limit (32766) exceeded at > /opt/local/lib/perl5/5.26/Locale/Po4a/TeX.pm line 697. > > That happens between line 11180 and 11200 of the file and it does not seem to be > triggered by any weird code. > > Checking the error on the web, I found that it is possibly related to using * in > a regex: > > https://metacpan.org/pod/XML::Easy::Syntax > >> BUGS >> >> Many of these regular expressions are liable to tickle a serious bug in perl's >> regexp engine. The bug is that the * and + repeat operators don't always match >> an unlimited number of repeats: in some cases they are limited to 32767 >> iterations. Whether this bogus limit applies depends on the complexity of the >> expression being repeated, whether the string being examined is internally >> encoded in UTF-8, and the version of perl. In some cases, but not all, a false >> match failure is preceded by a warning "Complex regular subexpression recursion >> limit (32766) exceeded". >> >> This bug is present, in various forms, in all perl versions up to at least 5.8.9 >> and 5.10.0. Pre-5.10 perls may also overflow their stack space, in similar >> circumstances, if a resource limit is imposed. >> >> There is no known feasible workaround for this perl bug. The regular expressions >> supplied by this module will therefore, unavoidably, fail to accept some >> lengthy valid inputs. Where this occurs, though, it is likely that other >> regular expressions being applied to the same or related input will also suffer >> the same problem. It is pervasive. Do not rely on this module (or perl) to >> process long inputs on affected perl versions. > > Line 697 of TeX.pm is: > > # detect \begin and \end (if they are not commented) > → if ($buffer =~ /^((?:.*?\n)? # $1 is > (?:[^%] # either not a % > | # or > (?<!\\)(?:\\\\)*\\%)*? # a % preceded by an odd nb of \ > ) # $2 is a \begin{ with the end of the line > (${RE_ESCAPE}(?:begin|end)\{.*)$/sx > > > If there could be a way to simplify this regex, maybe the issue would go away... > > org.texi is the only file in the emacs distribution that chokes on this regex. > > -- > Jean-Christophe Helary @brandelune > https://mac4translators.blogspot.com > https://sr.ht/~brandelune/omegat-as-a-book/ > _______________________________________________ > Devel mailing list -- devel(a)lists.po4a.org > To unsubscribe send an email to devel-leave(a)lists.po4a.org _______________________________________________ Devel mailing list -- devel(a)lists.po4a.org To unsubscribe send an email to devel-leave(a)lists.po4a.org