Unset special parameters

[Frank Terbeck <ft@bewatermyfriend.org>]

Hi list,

Since commit f3e7cfe47c32a23, some special parameters are initialised to
be unset. Among them PS1 and RPS1. Which means that prompt-themes need
to mark these parameters as global, because otherwise shells running
with ‘warn_create_global’ set will complain.

When I was trying to do that in my own theme, I was first trying this
(quite simplified):

#+BEGIN_SRC shell-script
prompt_ft_precmd () {
    # ...
    typeset -g RPS1
    RPS1='foo'
    # ...
}
#+END_SRC

...which still triggers the warning. Only when I assign a value to RPS1
in the typeset call, the warning goes away:

#+BEGIN_SRC shell-script
prompt_ft_precmd () {
    # ...
    typeset -g RPS1='foo'
    # ...
}
#+END_SRC

Is this a bug? Because, if I do this with a non-special parameter, it
works the way I'd expect it to:

[snip]
zsh% foo () {
    typeset -g BAR
    BAR=thingy
}
zsh% foo
zsh% echo $BAR
thingy
[snap]


Regards, Frank

-- 
In protocol design, perfection has been reached not when there is
nothing left to add, but when there is nothing left to take away.
                                                  -- RFC 1925