Comment 3 for bug 215903

That doesn't seem to address what Jamu wanted.

Specifically, it seemed he wanted to be able to do:

bzr pull
X revisions pulled

bzr diff -r -X

That generally won't work if the branch changes mainlines.

Further, if you include all revisions, it also won't work if there are any merges in what you are pulling.

I can understand displaying the number of new revisions (revisions in the ancestry of the new tip, that were not in the old tip). However, it doesn't necessarily fit the use case that was requested.

As for why we don't do it.... because we don't have an accurate and efficient function (yet) to compute it. 'graph.find_differences()' is approximately correct and efficient, but is not 100% accurate with all possible graphs.