Make $args available as global to match behavior of $argv and $argc

[kkmuffme]

Feature Request

• Yes, I reviewed the contribution guidelines.

Describe your use case and the problem you are facing

wp eval-file foo.php hello --skip-wordpress --use-include

In foo.php $args will be available as array containing 'hello' by default. However, when using
global $args; it will be null.
This is unintuitive, since for PHP $argv and $argc the global keyword is required, but when using this for $args it will have the opposite effect.

Describe the solution you'd like

The fix is simple by just setting global $args; before it's declared by WP-CLI.

[swissspidy]

Hmm it sounds like that variable might be unintentionally exposed to the script there. We can‘t change that without breaking existing usage, but I‘m wary of making this more explicitly visible.

What‘s your use case for that in the first place? The example looks like you might rather want to build your own proper command.

[kkmuffme]

My use case is exactly what this was implemented for and is documented as:

[<arg>]
One or more positional arguments to pass to the file. They are placed in the $args variable.

nothing unintentional about it?

[swissspidy]

Oh, didn‘t realize it was documented there 😅