Undefined batcher in SpinePipe.updateRenderable() with empty clipping vertices

[sta-ger]

When attempting to play one of the animations, I get the following error:

SpinePipe.ts:154 Uncaught
TypeError: Cannot read properties of undefined (reading 'updateElement')
    at SpinePipe.updateRenderable (SpinePipe.ts:154:44)
    at Xu.updateRenderable (RenderGroup.ts:187:65)
    at iE (RenderGroupSystem.ts:143:25)
    at Sl.render (RenderGroupSystem.ts:94:17)
    at Qo.emit (SystemRunner.ts:70:26)
    at L_.render (AbstractRenderer.ts:303:29)
    at lu.render (Application.ts:154:23)
    at li.emit (TickerListener.ts:64:26)
    at Pt.update (Ticker.ts:461:37)
    at Pt._tick (Ticker.ts:163:22)

The problem is that batchableSpineSlot.batcher is undefined during the execution of updateRenderable() at SpinePipe.

After some investigation, I've determined that in the addRenderable() method, the batchableSpineSlot for one of the attachments is marked as clipped but has an empty clippedData.vertices, which prevents this batchableSpineSlot from being added to the batch.

Adding one more condition that allows a slot with empty vertices to pass solves the problem.

Is it intentional that slots with empty clipping vertices are not allowed to be added to the batch?