Fix loading bundles on Flash

[dpomier]

This PR add missing fences around Sprite.__constructor for flash.

[joshtynjala]

This is likely not the correct solution. OpenFL has a custom extern for MovieClip that defines __constructor to support the swf library. It's likely that the extern for Sprite should also define its own __constructor for the same reason.

https://github.com/openfl/openfl/blob/6755608/lib/flash-externs/src/flash/display/MovieClip.hx#L11

[joshtynjala]

Actually, in the following commit, I can see where (on non-Flash targets) __constructor was moved from MovieClip to Sprite.

openfl/openfl@d579268

It appears that the Flash externs were accidentally omitted from this change. So my previous comment is on the right track, but may have some of the details wrong. __constructor may need to move from MovieClip to Sprite in the Flash externs too (rather than duplicating it). And then some mechanism needs to exist to call __constructor. Unfortunately, I don't have time at the moment to figure out the exact details.

@jgranick made the change for non-Flash targets. If he's available, he might know better what's needed to fix the Flash externs here.

[jgranick]

The trick here is we need to new MovieClip() then execute code immediately before we leave the class constructor.

MovieClip.__constructor is OpenFL's internal method to accomplish this. Later I moved it to Sprite.__constructor because Flash Professional/Adobe Animate allows a base class for Sprite and MovieClip symbols.

We're not in Flash internals, so non-Flash targets use a base class called flash.display.MovieClip2 which limps us to much of the same result:

https://github.com/openfl/openfl/blob/develop/lib/flash-externs/src/flash/display/MovieClip.hx

Options:

1.) Promote Sprite symbols to MovieClip on Flash (in order to use MovieClip2)
2.) Create an additional Sprite2 class on Flash
3.) Call __constructor on Flash manually after the object has been created
4.) Check if the object is MovieClip2 (__constructor was called automatically). If not, call __constructor manually before returning the object.

Option 4 seems like a good bet. There's already a check here (though seems redundant?)

swf/src/swf/exporters/animate/AnimateSpriteSymbol.hx

Line 108 in 79452c3

if (!#if (haxe_ver >= 4.2) Std.isOfType #else Std.is #end (sprite, flash.display.MovieClip.MovieClip2))

If not MovieClip2, we could call __constructor manually to run initializeSprite. Presumably, that would work fine.

IMHO options 1 and 2 are poor choices. Option 3 would remove the need for MovieClip2.__constructor, though would be a step back in functionality in some cases.

Here would be my action steps:

1.) Set MovieClip2.__constructor on Flash
2.) Create the object
3.) Check if the created object is a MovieClip2
4.) If yes, do nothing (__constructor was already called)
5.) If no, set MovieClip2.__constructor to null, and call __constructor manually on the object
6.) Return

[dpomier]

Thanks for the feedback. I've updated the PR with your suggestion, which seems to work just fine.

When testing, I had somehow the value "null" in frameObject.blendMode which led to an error in AnimateTimeline.__updateDisplayObject on Flash. I assume this is a different topic though.

[jgranick]

Thanks!