PATCH: 3.1.4: autocd to directory in $PATH (2)

[Peter Stephenson <pws@xxxxxxxxxxxxxxxxx>]

"Bart Schaefer" wrote:
> I haven't actually walked through this with a debugger, but it looks to
> me as though hn = NULL at that point is going to trigger the call to
> hashcmd(cmdarg, pathchecked), which in turn is going to call iscom() a
> second time; so you end up stat()ing the directory twice.

It does call hashcmd() again, but that's right... consider what can
happen otherwise:

% ./zsh -f
% mkdir ~/foo1 ~/foo2
% path=(~/foo1 ~/foo2 $path)
% cdpath=(~/foo1 .)      
% mkdir ~/foo1/file1
% echo "#\!/bin/sh\necho This is \$0" >~/foo2/file1
% chmod +x ~/foo2/file1
% setopt autocd
% file1                         # problem here:  cd's to ~/foo1/file1
~/foo1/file1
% pwd
/home/user2/pws/foo1/file1
% which file1
/home/user2/pws/foo2/file1
% file1                         # correct this time:  call ~/foo2/file1
This is /home/user2/pws/foo2/file1


The directory does get stat'ed twice, but it's hard to avoid without
more fiddling around with special cases.  The next fix does at least
mean it's restricted to twice altogether.

> Also, what about removing the improperly hashed directory from cmdnamtab
> once you've discovered that it isn't a command?  That would (I think) get
> any real command with the same name put into the table the next time that
> name was used, so that you'll never needlessly stat() again.

I meant to do that, there were only vague historical reasons why I
didn't.  Here's another replacement patch, this time for 4404.  I've
expunged an uncessary statbuf declaration, too.

*** Src/exec.c.hc	Mon Sep 28 10:37:43 1998
--- Src/exec.c	Mon Oct 12 14:10:37 1998
***************
*** 524,529 ****
--- 524,541 ----
  
  /**/
  int
+ isreallycom(Cmdnam cn)
+ {
+     char fullnam[MAXCMDLEN];
+ 
+     strcpy(fullnam, cn->u.name ? *(cn->u.name) : "");
+     strcat(fullnam, "/");
+     strcat(fullnam, cn->nam);
+     return iscom(fullnam);
+ }
+ 
+ /**/
+ int
  isrelative(char *s)
  {
      if (*s != '/')
***************
*** 1489,1494 ****
--- 1501,1511 ----
  	    char *cmdarg = (char *) peekfirst(args);
  
  	    hn = cmdnamtab->getnode(cmdnamtab, cmdarg);
+ 	    if (hn && !isreallycom((Cmdnam)hn)) {
+ 		cmdnamtab->removenode(cmdnamtab, cmdarg);
+ 		cmdnamtab->freenode(hn);
+ 		hn = NULL;
+ 	    }
  	    if (!hn && isset(HASHCMDS) && strcmp(cmdarg, "..")) {
  		for (s = cmdarg; *s && *s != '/'; s++);
  		if (!*s)

-- 
Peter Stephenson <pws@xxxxxxxxxxxxxxxxx>       Tel: +39 050 844536
WWW:  http://www.ifh.de/~pws/
Dipartimento di Fisica, Via Buonarotti 2, 56100 Pisa, Italy