Variable homebrew_uninstalled_packages is undefined

[mikesouza]

I think this is a bug, but I'm not sure if it's something with my particular ansible configuration (default) or what. Based on commits 50c72f2 and b5bb8f5, I can't tell whether it's just me getting this error or not.

In my existing and new playbooks dependent on this role, I MUST define the variable homebrew_uninstalled_packages: [] else I get the error above.

Anyways, the simple fix is to uncomment the homebrew_uninstalled_packages variable in defaults/main.yml. I'm just unsure if there was a reason for commenting it out in the first place.

Let me know if you need any further details. Thanks.

[elliotweiser]

IIRC, Ansible 2.0+ dislikes undefined variables, which seems to obviate the is defined check. My guess is the "best" (or at least easiest) fix is to uncomment the offending variable in defaults/main.yml, thus defining it. Sane default; easily overridden.

[geerlingguy]

There's another way of defining that when condition, though... I can't recall right now and can't look up in my recent commits to other roles, but you basically have to do two checks to see if it's defined and has a value—I think. It might be safer/more sane, otherwise I'm okay with just uncommenting that default var if it doesn't cause any other issues.

[mikesouza]

Thanks for the quick responses and feedback.

I've determined the root cause of the failed task; the with_items: {{ homebrew_uninstalled_packages }} is evaluated before the when: homebrew_uninstalled_packages is defined clause. This is intended behavior (See ansible/ansible#13950), and one solution is to change it to with_items: {{ homebrew_uninstalled_packages|default([]) }}.

However, IMO the better solution is to uncomment the line in defaults/main.yml and remove the when clause from the task altogether, for the following reasons:

• From the POV of someone new using this role, it's nice to be able to just look in the defaults/main.yml to see all available variables and defaults, especially when every other variable is defined and defaulted in this file. Similarly, the README remains consistent and unchanged; it currently mistakenly suggests that the homebrew_uninstalled_packages is defaulted to [] like the other documented variables.
• The task usage of homebrew_uninstalled_packages variable would become consistent and semantically the same as the task for installing packages via homebrew_installed_packages. I don't see a good reason why this task needs to be different, but please enlighten me if there's a use case I can't see.

I've submitted PR #67 with my proposed fix.

Thank you for your time.

[geerlingguy]

Fixed in above PR!