I was after the feature that Gerrit offers: diff the tip of a pull request to past tips. I learn that Bitbucket doesn't have that feature--which is a shame--so I'm trying to get close. I found out a post that suggests using REST API and jumping through all sorts of hoops to extract information from server.
I can view the diff I want locally if I could fetch the commits I need, but I don't seem to be able to do that either. I get:
fatal: Couldn't find remote ref SHA
Is there any way I can fetch commits I want from the server?