fix for detecting empty commit log message

[Mark Valentine]

CVS attempts to detect an empty or unchanged log message from a commit
log editing session, but misses a case where someone tries to abort a
commit by deleting all but the CVS: lines before quitting the editor
(it does detect the case where the leading blank line inserted by older
versions is left in).

The patch below detects this case, which I know has caught many people
out over the years, but I'd always put down to the effects of a very simple
detection algorithm rather than a bug (until I finally looked at the code
just now, trying to be more clever than I'd had it down for).

My (simple) testing was actually done using a similar patch against the
version of CVS in the current FreeBSD CVS repository - I don't have the
latest CVS code checked out in its entirety here.

                Cheers,

                Mark.

Index: logmsg.c
===================================================================
RCS file: /cvsroot/ccvs/src/logmsg.c,v
retrieving revision 1.51
diff -u -r1.51 logmsg.c
--- logmsg.c    16 Apr 2001 17:49:32 -0000      1.51
+++ logmsg.c    16 Jun 2001 02:36:59 -0000
@@ -337,7 +337,7 @@
        error (0, errno, "warning: cannot close %s", fname);
 
     if (pre_stbuf.st_mtime == post_stbuf.st_mtime ||
-       *messagep == NULL ||
+       *messagep == NULL || (*messagep)[0] == '\0' ||
        strcmp (*messagep, "\n") == 0)
     {
        for (;;)

-- 
Mark Valentine, Thuvia Labs <mark@thuvia.co.uk>       <http://www.thuvia.co.uk>
"Tigers will do ANYTHING for a tuna fish sandwich."       Mark Valentine uses
"We're kind of stupid that way."   *munch* *munch*        and endorses FreeBSD
  -- <http://www.calvinandhobbes.com>                  <http://www.freebsd.org>