animation.play() with Reversed==true not working as expected

[starry-abyss]

• Haxe version: 3.4.2
• Flixel version: a5cb05d
• OpenFL version: 3.6.1
• Lime version: 2.9.1
• Affected targets: flash, neko

---

Code snippet reproducing the issue:

package;

import flixel.FlxState;
import flixel.FlxSprite;
import flixel.util.FlxColor;

class PlayState extends FlxState
{
    override public function create():Void
    {
        var playerSprite = new FlxSprite();
        playerSprite.makeGraphic(100, 100, FlxColor.GREEN);
        add(playerSprite);

        playerSprite.animation.add("test", [0, 0, 0, 0], 6, false);
        playerSprite.animation.callback = function(name, number, index) {
            trace("callback", playerSprite.animation.finished, name, number, index);
        };

        playerSprite.animation.play("test", true, true);
    }
}

---

Observed behavior:

On Flash:

PlayState.hx:45: callback,false,test,3,0
PlayState.hx:45: callback,false,test,2,0
PlayState.hx:45: callback,false,test,1,0
PlayState.hx:45: callback,false,test,0,0
PlayState.hx:45: callback,false,test,-1,0
PlayState.hx:45: callback,false,test,-2,0
PlayState.hx:45: callback,false,test,-3,0
PlayState.hx:45: callback,false,test,-4,0
PlayState.hx:45: callback,false,test,-5,0
PlayState.hx:45: callback,false,test,-6,0
PlayState.hx:45: callback,false,test,-7,0
...

On neko:

PlayState.hx:45: callback,false,test,3,0
PlayState.hx:45: callback,false,test,2,0
PlayState.hx:45: callback,false,test,1,0
PlayState.hx:45: callback,false,test,0,0
Invalid operation (%)
Called from flixel.animation.FlxAnimationController::set_frameIndex line 725
Called from flixel.animation.FlxBaseAnimation::set_curIndex line 32
Called from flixel.animation.FlxAnimation::set_curFrame line 243
Called from flixel.animation.FlxAnimation::update line 197
Called from flixel.animation.FlxAnimationController::update line 87
Called from flixel.FlxSprite::updateAnimation line 629
Called from flixel.FlxSprite::update line 621
Called from flixel.group.FlxTypedGroup::update line 141
Called from PlayState::update line 59
Called from flixel.FlxState::tryUpdate line 172
Called from flixel.FlxGame::update line 735
Called from flixel.FlxGame::step line 665
Called from flixel.FlxGame::onEnterFrame line 538
Called from openfl._legacy.events.EventDispatcher::dispatchEvent line 98
Called from openfl._legacy.display.DisplayObject::__dispatchEvent line 182
Called from openfl._legacy.display.DisplayObject::__broadcast line 161
Called from openfl._legacy.display.DisplayObjectContainer::__broadcast line 286
Called from openfl._legacy.display.Stage::__render line 1103
Called from openfl._legacy.display.Stage::__checkRender line 351
Called from openfl._legacy.display.Stage::__pollTimers line 1084
Called from openfl._legacy.display.Stage::__doProcessStageEvent line 430

Expected behavior:

Should be same as when Reversed==false (but with reversed frame order):

PlayState.hx:45: callback,false,test,3,0
PlayState.hx:45: callback,false,test,2,0
PlayState.hx:45: callback,false,test,1,0
PlayState.hx:45: callback,false,test,0,0
PlayState.hx:45: callback,true,test,0,0