[Bug libstdc++/58576] New: std::regex_match() reports mismatched braces on a valid regex

[Bug libstdc++/58576] New: std::regex_match() reports mismatched braces on a valid regex

[galens at capaccess dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58576

            Bug ID: 58576
           Summary: std::regex_match() reports mismatched braces on a
                    valid regex
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: galens at capaccess dot org

Created attachment 30929
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30929&action=edit
Archive containing the g++ -v -save-temps compile log, the generated .ii file
and the original .cpp with the minimum-to-reproduce test case.

I attempted to use a regex to validate qualified hostnames.

However, when I used the regex from this thread (
http://stackoverflow.com/questions/1418423/the-hostname-regex ), with or
without replacing the [0-9A-Za-z] with [:alnum:] (and properly escaping the
backslashes), I get a regex_error exception thrown on std::regex_match() call,
with a regex_constants::error_brack as the reported code().


Using: An unmodified copy of gcc 4.8.1 20130603 from the Fedora 19 primary
repository (rpm ver: 4.8.1-1.fc19 )

(I use 4-spaces-per-tab in my source code, which isn't relevant for the code,
but might make hand-tracing of Parens, Braces, and Brackets I did in comments
more understandable.) 

(And, yes, I know replacing [0-9A-Za-z] with [:alnum:] isn't a legitimate
change WRT domain name validity, unless I force a 'C' locale.  It was just
easier to read when hunting down this issue.)

[Bug libstdc++/58576] std::regex_match() reports mismatched braces on a valid regex

[galens at capaccess dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58576

Galen G Brownsmith <galens at capaccess dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #30929|0                           |1
        is obsolete|                            |

--- Comment #1 from Galen G Brownsmith <galens at capaccess dot org> ---
Created attachment 30930
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30930&action=edit
re-uploading my tar.gz -- fixed an independent but potentially distracting
typo.

There was a case where part of the regex read "(?(?:" rather than "(?:(?:". 
Fixed that, behvior remains.

[Bug libstdc++/58576] std::regex_match() reports mismatched braces on a valid regex

[schwab@linux-m68k.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58576

--- Comment #2 from Andreas Schwab <schwab@linux-m68k.org> ---
[:alnum:] only matches the six characters ":almnu".  If you want to match any
letter or digit you have to write [[:alnum:]].

[Bug libstdc++/58576] std::regex_match() reports mismatched braces on a valid regex

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58576

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |DUPLICATE

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
<regex> doesn't work in GCC 4.8

Your test works with the GCC trunk, where the work to implement regex is being
done.

*** This bug has been marked as a duplicate of bug 53631 ***

[Bug libstdc++/58576] std::regex_match() reports mismatched braces on a valid regex

[timshen at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58576

--- Comment #4 from Tim Shen <timshen at gcc dot gnu.org> ---
Author: timshen
Date: Tue Oct  1 15:26:50 2013
New Revision: 203067

URL: http://gcc.gnu.org/viewcvs?rev=203067&root=gcc&view=rev
Log:
2013-10-01  Tim Shen  <timshen91@gmail.com>

    PR libstdc++/58576
    * include/bits/regex_automaton.tcc (_NFA<>::_M_eliminate_dummy)
    (_StateSeq<>::_M_clone): Add _S_opcode_subexpr_lookahead branch.
    * testsuite/28_regex/algorithms/regex_match/ecma/char/58576.cc: New.

Added:
   
trunk/libstdc++-v3/testsuite/28_regex/algorithms/regex_match/ecma/char/58576.cc
Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/bits/regex_automaton.tcc