bug#15758: grep 2.15 calls abort() on larger searches with -P

[Dave Reisner]

Hi,

A user reported a regression with grep 2.15 which is reasonably easy to
reproduce with an invocation such as: ``grep -Pr foo''. The root cause
is that pcre_exec returns an unhandled error (PCRE_ERROR_BADUTF8)
causing grep to call abort().

I bisected the breakage to commit 67436786c110bbb565 (and verified that
it still exists at git HEAD) which essentially introduces utf-8
validation for data. On a large enough file hierarchy, I suppose it's
inevitable that invalid UTF-8 data is encountered. I was able to fix
this with the inline diff which follows:

  diff --git a/src/pcresearch.c b/src/pcresearch.c
  index ad5999d..ce55ab3 100644
  --- a/src/pcresearch.c
  +++ b/src/pcresearch.c
  @@ -176,6 +176,9 @@ Pexecute (char const *buf, size_t size, size_t 
*match_size,
         switch (e)
           {
           case PCRE_ERROR_NOMATCH:
  +#ifdef HAVE_LANGINFO_CODESET
  +        case PCRE_ERROR_BADUTF8:
  +#endif
             return -1;

           case PCRE_ERROR_NOMEMORY:

I don't know if this is considered to be a correct fix, but I offer it
as a starting point for a discussion.

Cheers,
Dave

P.S. Please CC me on replies as I am not subscribed to the list.