How about diffs on pull request? The biggest gripe I have with github is the inability to compare my feature branch with the branch I'm merging too. The diff you see is comparing the feature branch with the "base" branch which would be stale when working on a dev team.
- Two feature branches were created based on master at the same time.
- Branch1: committed a change to readme and it's pulled into master via PR.
- Branch2: committed a change to readme, raised a pull request (PR#3), and the diff doesn't show the line that was added with the branch1 pull request.
In this example, the PR is telling me there's a conflict and I need to merge master with the PR branch (this is good). What it doesn't tell me is where the conflict is.
Solution, merge the base branch into the interim PR branch. The result will show you the conflict and properly represents what would happen if this PR is accepted. (Bitbucket does this)