AnimationPlayer should return error when attempting to play animation that doesn't exist

[Feniks-Gaming]

Describe the project you are working on:

Breakout clone

Describe the problem or limitation you are having in your project:

Currently $AnimationPlayer.play("animation_name_that_doesn't_exist") will do nothing it will simply not play any animation. This is not desired because it makes it hard to track bugs.

This usually happens when user misspells animation name and is not something any user could possibly want as desired behaviour.

Describe how this feature / enhancement will help you overcome this problem or limitation:

$AnimationPlayer.play("animation_name_that_doesn't_exist") should return error Attempting to play animation that doesn't exist so user knows immediately that that there is an error

Show a mock up screenshots/video or a flow diagram explaining how your proposal will work:

N/A

Describe implementation detail for your proposal (in code), if possible:

Not sure

If this enhancement will not be used often, can it be worked around with a few lines of script?:

Used by everyone and no current work around hat I know off.

Is there a reason why this should be core and not an add-on in the asset library?:

It's a pare of core behaviour of one of core nodes.

[Janders1800]

if animationPlayerNode.has_animation("animationToPlay"):
    animationPlayerNode.play("animationToPlay")
else:
    push_error(Animation: animationToPlay, ", not found on: ", animationPlayerNode.get_name())

[Feniks-Gaming]

It should do it by default. I shouldn't have to add 2 lines of code every time for his to happen.

[timothyqiu]

I think animation existence has already been checked: https://github.com/godotengine/godot/blob/43caf83c0973c22b54f28e84aa23e2c6d501fe1f/scene/animation/animation_player.cpp#L1150-L1157

Both 3.1.2 and current master produce this error:

ERROR: play: Animation not found: animation_name_that_doesn't_exist.