Turns out the problem I ran into was a clash between dirtrack-mode and shell-dirtrack-mode. I had no idea there were two competing packages; the problem was that dirtrack picked up the new path, then shell-dirtrack noticed the “cd ..”.
Solved:

(add-hook ’shell-mode-hook
(lambda ()
[...]

I downloaded Carbon Emacs today, to consider it as a replacement for Aquamacs. It seems nice enough, and passes the sniff test.
My problem is that I have many hours of work invested in tweaking Aquamacs to behave the way I like. And I’m not just referring to Aquamacs settings, I have the usual collection of [...]

One of the problems I’ve had with various emacsen is the shell dirtrack support. This keeps the shell-mode’s idea of what directory you’re in in sync with which one you’re actually in. At least in Aquamacs, this support is not very good, and it will break if you use bash features like CDPATH or “cd [...]

It seems like Aquamacs has been going downhill lately. I’ve been running 1.4 since it came out, and recently upgraded to 1.5RC1. They’re both quite buggy.

1.4 introduced tabs via modification of tabbar.el. This is something I’ve desired for some time, but the implementation is lacking.

If you close the only buffer in a frame, the frame [...]

One of the thing I often need is a shell in the same directory as a file I’m editing. Emacs doesn’t have a quick way to do this, so I hacked one together.

(defun shell-here ()
“Open a shell in `default-directory’.”
(interactive)
(let ((dir (expand-file-name default-directory))
[...]