Ansible tab completion: re-read cached hosts & groups on directory change

[Moritz Bunkus <mo@bunkus.online>]

Hey,

zsh 5.8

we have several Ansible repositories in different directories. I often have
to switch between them.

Unfortunately the tab completion for all the Ansible commands caches known
Hosts & Groups in the global variables _ansible_hosts &
_ansible_groups. For me the effect is that the wrong set of hosts & groups
is offered when I change to a different Ansible repo.

How to reproduce:

1. Have two or more Ansible repositories with different inventories
   somewhere
2. cd into /path/to/first_ansible_tree
3. Type `anssible <TAB>`, let tab completion cache hosts & groups
4. Hit <TAB> again to verify that the offered completions match expected
   ones
5. cd into /path/to/other_ansible_tree
6. Type `ansible <TAB><TAB>` and observe that the offered completions still
   come from the first_ansible_tree, not from other_ansible_tree

As a quick workaround I've modified the completion to also cache the
working directory where _ansible_hosts & _ansible_groups were created. If
the current working directory doesn't match the cached working directory,
both variables are unset & their values cached again. This seems to work.

The attached patch implements this. Feel free to use it however you want,
or to apply a totally different solution.

Thanks.

Kind regards,
mosu

--- /usr/share/zsh/functions/Completion/Unix/_ansible	2020-02-16 18:55:21.000000000 +0100
+++ /home/mosu/.config/zsh/functions/_ansible	2022-01-07 09:43:00.841820539 +0100
@@ -204,10 +204,15 @@
     else
       local -a inventory
       typeset -ga _ansible_hosts _ansible_groups
+      typeset -g _ansible_inventory_last_cwd
+      if [[ $PWD != $_ansible_inventory_last_cwd ]]; then
+        unset _ansible_hosts _ansible_groups
+      fi
       if (( !$#_ansible_hosts || !$#_ansible_groups )); then
        	inventory=( ${(f)"$(_call_program groups ansible-inventory --graph)"} )
        	_ansible_hosts=( ${${(M)inventory%--[^:]#}#--} )
 	_ansible_groups=( ${${${(M)inventory%@*:}%:}#@} )
+        _ansible_inventory_last_cwd=$PWD
       fi
       [[ $IPREFIX = *[:,] ]] &&
 	alts=( 'operators:operator:_values -S "" operator "![exclude hosts]" "&[intersection of hosts]" "~[regular expression pattern]"' )