Re: `exec env -i OLDPWD=$OLDPWD zsh` doesn't work

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Fri, 13 Jan 2017, Peter Stephenson wrote:

> OLDPWD seems to be slightly weirdly implemented at the moment.  There's
> an internal variable storing it, but that's not explicitly tied to a
> shell variable; instead when the internal variable gets changed
> the shell variable also gets changed.  So the internal variable isn't
> changed if you change the shell variable

This is actually semantically necessary, as I recall.  There's no
prohibition on using OLDPWD and PWD as ordinary variables, as long as
you don't "cd" along the way.

And assigning to them is not supposed to behave like a "cd" or to
change the way "cd -" works, as far as I can tell.

Please don't make them into specials, we'll just have to find a way to
un-special them again for POSIX compatibility or something.