🚀 go-pugleaf

A search performed by isearch-forward-regexp sometimes fails when it
should not.  A precise example is given by the following dribble after
entering emacs via the command "emacs -q":

--begin dribble
The quick brown fox jumps over the lazy dog.
--end dribble

Here's the same dribble with control characters translated, in case they
don't make it through some mailer:
--begin dribble
The quick brown fox jumps over the lazy dog.^M^P^[^Sjumps\|brown^A^[^Sjumped\|brown^A^X^C
--end dribble


The string returned by emacs-version is:

	GNU Emacs 18.41.16 of Wed Apr 29 1987 on slocum (berkeley-unix)

The first search correctly jumped back to the starting point when I
typed "\|" to start the alternation.  In the second search, the first
alternative ultimately failed after a prefix was located, and when I
typed "\|" the cursor jumped back to the beginning of the prefix
rather than the origin of the search.  A successful match of the
second alternative appearing before that point was subsequently not
located.

The same regexp supplied to re-search-forward works correctly.

-Andy Lowry