Expose EditorToaster API for plugins

[dalexeev]

Toast notifications can be a good alternative to OS.alert() (forces the user to click OK) and push_error()/push_warning() (may not be noticed by the user).

[ashifolfi]

I heavily agree with this! Working with someone who is a non coder and gets very confused with programming related things I found that there's no real easy way for me to display notices from my graphical editors to them without dialogs or making them go into a debug log.

having the option to make push notifications for these things would be extremely useful to me in my mission to make my friend feel more directly involved with the development of the project without overwhelming them.

[Calinou]

We could make the push_error() and push_warning() exposed to GDScript use ERR_PRINT_ED and WARN_PRINT_ED instead of ERR_PRINT and WARN_PRINT respectively. This way, all usage of push_error() and push_warning() within editor plugins or @tool scripts will display toasts in the editor.

This wouldn't make it possible to spawn informational toasts though (SEVERITY_INFO) – not until we implement #1378.

https://github.com/godotengine/godot/blob/e7d2e49688bdaec65e326e7b2bfcc0642b4f2a8d/core/variant/variant_utility.cpp#L905

https://github.com/godotengine/godot/blob/e7d2e49688bdaec65e326e7b2bfcc0642b4f2a8d/core/variant/variant_utility.cpp#L925

Edit: Pull request opened: godotengine/godot#77890

[Calinou]

Proposal issue opened: #11051