Add method to ProjectSettings that returns all action names from input/*

[Pennycook]

The InputMap documentation says that trying to access it inside the editor returns events for the editor, and that the mapping for the project itself must be accessed using the input/* settings from ProjectSettings instead.

However, the following only works if the list of actions is known:

ProjectSettings.get_setting("input/" + action)

...and so there seems to be no way to emulate the functionality of InputMap.get_actions() within the editor.

Being able to call something like ProjectSettings.get_actions() or ProjectSettings.get_settings("input/") would enable developers to use the contents of the InputMap inside of an EditorPlugin or inside of a script's _get_property_list() function. In my case, it would enable me to configure a drop-down box in the inspector that allows the user to select an action.

EDIT: I've just discovered that it's possible to work around this by iterating through ProjectSettings.get_property_list(), which wasn't obvious. If this is the intended solution, I'll open an issue against the documentation instead.

[PadraigK]

I'm working on a code generator and would also love to be able to list InputMaps like this. I really appreciate you sharing the work around, I'll see how far I can get using that.

[winston-yallow]

Another usecase: I am making a plugin for easy input remapping at runtime. For this I let the developer choose in the editor which input actions to expose to the end user. Currently parsing the ProjectSettings is a bit cumbersome (but possible):

for setting in ProjectSettings.get_property_list():
    if setting.name.begins_with('input/'):
        prints(setting.name, ProjectSettings.get_setting(setting.name))

It think the project settings could benefit from a general purpose method ProjectSettings.get_settings(filter), where the filter is optional to only get a subset of settings.

[winston-yallow]

Created a formal proposal #8464