[Bug c++/86165] New: std::regex crashes when matching long lines.

[holger.seelig at yahoo dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86165

            Bug ID: 86165
           Summary: std::regex crashes when matching long lines.
           Product: gcc
           Version: 7.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: holger.seelig at yahoo dot de
  Target Milestone: ---

std::regex crashes when matching long lines.

Here is an example:


#include <regex>
#include <iostream>

int main()
{
    std::string s (100'000, '*');
    std::smatch m;
    std::regex r ("^(.*?)$");

    std::regex_search (s, m, r);

    std::cout << s .substr (0, 10) << std::endl;
    std::cout << m  .str (1) .substr (0, 10) << std::endl;
}


It turns out that std::regex_search operator .* is implemented recursively
which result in this example in a stack overflow.