bug#4175: 23.1; nxml-mode: Internal error in rng-validate-mode triggered

[Stefan Kangas]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Stephen Berman <stephen.berman@gmx.net>
>> Cc: Andrew Hyatt <ahyatt@gmail.com>,  4175@debbugs.gnu.org
>> Date: Fri, 12 Feb 2016 11:12:23 +0100
>>
>> I can reproduce it in a91b4b51ddf2575d821adb8b84fdf32cff83886e (GNU
>> Emacs 25.0.90.2 (x86_64-suse-linux-gnu, GTK+ Version 3.14.15) of
>> 2016-02-11).
>
> How large is the run-time stack on that system?
>
>> Here's the backtrace:
>>
>> Debugger entered--Lisp error: (error "Stack overflow in regexp matcher")
>>   
>> looking-at("\\(\\(?:\\(xmlns\\)\\|[_[:alpha:]][-._[:alnum:]]*\\)\\(:[_[:alpha:]][-._[:alnum:]]*\\)?\\)[
>>      \n]*=\\(?:[
>>      \n]*\\('[^<'&
>> \n   ]*\\([&
>> \n   ][^<']*\\)?'\\|\"[^<\"&
>> \n   ]*\\([&
>> \n   ][^<\"]*\\)?\"\\)\\(?:\\([
>>      \n]*>\\)\\|\\(?:\\([
>>      \n]*/\\)\\(>\\)?\\)\\|\\([
>>      \n]+\\)\\)\\)?")
>>   xmltok-scan-attributes()
>>   xmltok-scan-after-lt()
>>   xmltok-forward()
>>   rng-forward()
>>   rng-do-some-validation-1(rng-validate-while-idle-continue-p)
>>   rng-do-some-validation(rng-validate-while-idle-continue-p)
>>   rng-validate-while-idle(#<buffer url25099xa>)
>
> Thanks.  Perhaps some regexp guru could suggest how to make this
> regexp less greedy.

Maybe Mattias could take a look?