[jessaustin]

Atlassian are talking about a real problem here, which problem they appear to have solved. Working code is usually superior to social convention (rebase, etc.); that's why we're using git (or possibly other DVCSs) instead of RCS, etc.

[jMyles]

Not sure I agree. In either case, both a social convention and an expected response from the executed command are necessary because both the "double dot" and "triple dot" logic are necessary to truly understand the implications of a complex pull request.

In the case of Atlassian's solution, the "merged" social convention will have to be use to first use and personally verify the "triple dot" findings in order to review that the change to the branch is, in isolation, as expected - before proceeding through the "double dot" flow that now characterizes the pull request feature.

For Github, it's simply the inverse.

Either way, both are relatively easy to achieve with the command line or a diff tool like Meld or LiClipse.