Re: zsh segfault

[Bart Schaefer <schaefer@brasslantern.com>]

On Aug 24, 11:23am, Thomas Eriksson wrote:
> 
> printf "unset -f precmd \n" 1>/home/arne/wuf
> alias wuf="echo wuf wuf;precmd () { . /home/arne/wuf ; }"
> wuf

The alias isn't necessary; so is the unset -f.  Any "." or "source"
command from within precmd() gives:

BUG: chline is NULL in hend()

(which is only visible with configure --enable-zsh-debug).

This is happening because source() re-enters loop(), which clobbers the
hbegin(1) at the top of the function.  The following fixes it, but I'm
wondering if there's a better way.

(The reason this doesn't happen in 3.0.x is that the hbegin() in loop()
happens later, after preprompt() -- but 4.0.x has a bunch of special
variables that might be used in `precmd' and that refer to the history,
so the initialization has to happen sooner.)

Index: Src/init.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/init.c,v
retrieving revision 1.18.4.1
diff -c -r1.18.4.1 init.c
--- Src/init.c	2001/06/30 18:30:07	1.18.4.1
+++ Src/init.c	2001/08/24 22:53:36
@@ -107,6 +107,8 @@
     pushheap();
     for (;;) {
 	freeheap();
+	if (stophist == 3)	/* re-entry via preprompt() */
+	    hend(NULL);
 	hbegin(1);		/* init history mech        */
 	if (isset(SHINSTDIN)) {
 	    setblock_stdin();
@@ -114,7 +116,10 @@
 	        int hstop = stophist;
 		stophist = 3;
 		preprompt();
-		stophist = hstop;
+		if (stophist != 3)
+		    hbegin(1);
+		else
+		    stophist = hstop;
 		errflag = 0;
 	    }
 	}