This is a possible bug report:
Textmate 2.0-alpha.9495 crashes (or rather, gets stuck) when executing a command which has both of these options defined:
Semantic Class: callback.document.will-save Save: Current Document
As in screenshot: http://i.imgur.com/1ghCVC3.png
Nobody would *want* to set both of these, but I thought mention this in case, as it happened to me, you set them inadvertently.