bug#20230: 24.4.91; slow regexp

[Nicolas Richard]

Consider this snippet:

(with-temp-buffer
  (insert "**** foo\n")
  (insert ":PROPERTIES:\n")
  (dotimes (_ 7) (insert ":a:     \n"))
  (insert ":bar: foo\n\n:END:")
  (goto-char 10) ;; beginning of second line
  (looking-at "^[       ]*:PROPERTIES:[         ]*
\\(?:[  ]*:\\S-+:\\(?: .*\\)?[  ]*
\\)*[   ]*:END:[        ]*$"))

If that doesn't take several seconds, increasing the number 7 to 8, 9 or
more probably will. It does for me.

The regexp is one from org mode.

(It was suggested that a file this as a separate bug report in
http://debbugs.gnu.org/cgi/bugreport.cgi?bug=20191#28)

-- 
Nicolas