Re: zsh exits after delete-char-or-list and two ^Cs

[Peter Stephenson <pws@csr.com>]

Danek Duvall wrote:
> This happens with 4.0.6, 4.2.0 and 4.2.1, the first two on Linux, the
> latter on Solaris.  If I use delete-char-or-list, then hit control-C twice,
> the first time cancels the command-line where I hit ^D, and the second one
> exits the shell.

Obviously if I tried to look at this today after my holiday it would
just get me all frustrated.  So that would be a bad idea.

Here's a patch.  The problem is that there's a special test to see if
there was an EOF character (which must be ^D for the bug to turn up in
this particular form) at the start of the line.  This test was
erroneously triggered on the second ^C as the input character hadn't
changed from the ^D used to list completion.  The first ^C didn't
trigger it because the line hadn't yet been emptied.  The functions
don't pass back the state properly, so it's difficult to check what
actually happened (i.e. EOF or interrupt); maybe it can be done better
than this.

Note that errflag isn't set at the point of the patch if there was a ^C.
This seems to be deliberate; see the handling of EINTR in getkey().  I
think it's also to do with the lack of distinction between an
interruption and an EOF---in loop(), we exit the command loop, and
hence the shell, if we get an end-of-input token and errflag is *not* set.

I thought about resetting lastchar at the start of each line.  However,
I think there are cases where that doesn't work.

Index: Src/Zle/zle_main.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Zle/zle_main.c,v
retrieving revision 1.49
diff -u -r1.49 zle_main.c
--- Src/Zle/zle_main.c	13 Jul 2004 09:41:37 -0000	1.49
+++ Src/Zle/zle_main.c	1 Sep 2004 17:15:15 -0000
@@ -687,12 +687,19 @@
 	reselectkeymap();
 	selectlocalmap(NULL);
 	bindk = getkeycmd();
-	if (!ll && isfirstln && !(zlereadflags & ZLRF_IGNOREEOF) &&
-	    lastchar == eofchar) {
-	    eofsent = 1;
-	    break;
-	}
 	if (bindk) {
+	    if (!ll && isfirstln && !(zlereadflags & ZLRF_IGNOREEOF) &&
+		lastchar == eofchar) {
+		/*
+		 * Slight hack: this relies on getkeycmd returning
+		 * a value for the EOF character.  However,
+		 * undefined-key is fine.  That's necessary because
+		 * otherwise we can't distinguish this case from
+		 * a ^C.
+		 */
+		eofsent = 1;
+		break;
+	    }
 	    if (execzlefunc(bindk, zlenoargs))
 		handlefeep(zlenoargs);
 	    handleprefixes();

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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