My students currently submit their code in Bitbucket and create a pull request. Bitbucket has a code review tool that allows me to create comments tied to specific lines in the code. I really like this. However, it only lets me comment on the diff, so I can only comment on code in the most recent commit. I want to be able to comment on the entire source file. Is there a tool that lets me do that in a similar fashion?
The diff is between the most recent commit and the start of the branch. It's not just the diff of the last commit, it's every commit (stacked on top of each other) since the branch's origins.
If that weren't the case, it'd be nigh impossible to provide meaningful feedback to a code review for a branch's pull request.