java.lang.IllegalArgumentException: History may not be empty

This exception occurs when Flow.goBack() is called during a transition and History.size() == 1.

The code in Flow.goBack() should just return true if a transition is in progress otherwise the builder.pop call removes the last key and setHistory crashes with an IllegalArgumentException.

[osama-lionheart]

@GrahamRogers this is the same as #195

[Zhuinden]

This is because you shouldn't call super.onBackPressed during a transition

[rjrjr]

Closing as a dup of #195

[rjrjr]

See also #197