Hi, This issue is due to the fact that valac-0.32-vapi_0.32.0-1 integrates bindings from gtk+ 3.19 which don't exist in the gtk+ version currently in testing. I'll file a bug because this will be a problem for other packages too.
Can we postpone the auto-removal of my package as it's not an issue due to it but due to a dependent package? Thanks Joseph