bug#18577: Regexp I-search: [(error Stack overflow in regexp matcher)]

[Tassilo Horn]

We have a similar bug report for AUCTeX/RefTeX, although the regex
doesn't look that bad as Alan's.

Too reproduce, create a file with 10000 lines with the word foo, and
evaluate this:

  (re-search-forward "^[^%]*\\\\usepackage.*{biblatex}" nil t)

Here, there's no double-* or nested-* but still you get a stack overflow
in the regexp matcher.

Ah, the problem here is that [^%] also matches \n.  I've just seen that
this regex has already been fixed to

  "^[^%\n]*?\\\\usepackage.*{biblatex}"

on master, and I've backported the fix to the emacs-24 branch.

Bye,
Tassilo