We are evaluating upsource as a replacement for reviewboard, which we'll often use for reviewing branches. How does upsource decide what is in a branch review? In reviewboard, or gitlab it is fairly simple to say develop..feature_foo or master..feature_bar (in Reviewboard by just specifying it like that; with Gitlab by having the merge request source and target branches).
We can't figure out how to do something similar in Upsource; it seems to take a guess, and at least in one of our cases the guess was wrong and doesn't include many of the revisions we care about. We can compare the branches from the tool; but can't figure out how to create a review out of precisely those revisions (and then hopefully track the head).
It looks like upsource is cutting off the review at the first commit that is in more than one branch; but that is no good for us, because we can cases where we have two branches off of develop with one merged into the other.