Re: `popd' is blocked on non-existent directory

["Bart Schaefer" <schaefer@candle.brasslantern.com>]

On Oct 15,  7:02pm, John S Cooper wrote:
} Subject: `popd' is blocked on non-existent directory
}
} Under zsh 3.0.0, if a directory in the directory stack is removed, popd
} seems to get "blocked".  In 2.5, the non-existent directory would just be
} removed from the stack.
} 
} Is there a way to get the old behavior, i.e. have all non-existent
} directories removed from the stack?

--- Src/builtin.c.0	Tue Oct  8 10:30:08 1996
+++ Src/builtin.c	Tue Oct 15 21:23:49 1996
@@ -1082,6 +1082,8 @@
     if (!(dest = cd_do_chdir(nam, getdata(dir)))) {
 	if (!target)
 	    zsfree(getlinknode(dirstack));
+	if (func == BIN_POPD)
+	    zsfree(remnode(dirstack, dir));
 	return NULL;
     }
     if (dest != getdata(dir)) {

} Also, when there's only one entry left on the dir stack, (I think) a popd
} used to remove it and pop me to my home directory.  This is no longer the
} case in 3.0.0 .

The compatible-with-other-shells behavior in this case would be to issue a
`directory stack empty' error message.  (However, I could see an argument
that PUSHD_TO_HOME ought to apply to popd as well.)

What the code is actually doing is pushing the home directory onto the
stack (without actually doing the chdir) and then popping it back off
again.  Then it executes chdir to the top of the stack, that is, to the
directory it's already in:

zagzig[65] ./zsh -f
zagzig% chpwd() { echo CHPWD }
zagzig% popd
/usr/src/local/zsh/zsh-3.0.1-test3/Src
CHPWD
zagzig% popd
/usr/src/local/zsh/zsh-3.0.1-test3/Src
CHPWD

This seems like a lot of wasted effort, particularly considering that
chpwd gets run each time.

--- Src/builtin.c.0	Tue Oct  8 10:30:08 1996
+++ Src/builtin.c	Tue Oct 15 22:20:21 1996
@@ -1019,11 +1019,15 @@
     char *dest;
 
     if (!argv[0]) {
+	if (func == BIN_POPD && !nextnode(firstnode(dirstack))) {
+	    zwarnnam(nam, "directory stack empty", NULL, 0);
+	    return NULL;
+	}
 	if (func == BIN_PUSHD && unset(PUSHDTOHOME))
 	    dir = nextnode(firstnode(dirstack));
 	if (dir)
 	    insertlinknode(dirstack, dir, getlinknode(dirstack));
-	else
+	else if (func != BIN_POPD)
 	    pushnode(dirstack, ztrdup(home));
     } else if (!argv[1]) {
 	int dd;
@@ -1069,7 +1073,6 @@
     target = dir;
     if (func == BIN_POPD) {
 	if (!dir) {
-	    zsfree(getlinknode(dirstack));
 	    target = dir = firstnode(dirstack);
 	} else if (dir != firstnode(dirstack)) {
 	    return dir;

-- 
Bart Schaefer                             Brass Lantern Enterprises
http://www.well.com/user/barts            http://www.nbn.com/people/lantern

New male in /home/schaefer:
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