git多分支差异？

Question

Is there an easy way to get the diff between multiple (more than two) branches with git? (Something like an "octopus diff"?)

The situation is that there is a branch (call it branch A) which is the result of a merge of multiple other branches (call them B and C) along with other modifications. (Branch A diverged from branch B, had a number of local modifications, then branch C was merged in, followed by more local modifications, then even more local modifications and re-merging to include updates on the B and C branches.)

What I'd like to do is see all local changes unique to branch A - that is, see what changes have been made to branch A that aren't on either branch B or branch C.

Answer 1

Make a branch "bPlusC" off of B, and then merge "C". Diff that with "A".

git checkout -b bPlusC B
git merge --no-ff C
git checkout A
git diff bPlusC..HEAD

EDIT: Based on RM's comment:

If B or C have commits that are not in A use this:

git checkout -b bPlusC $(git merge-base A B)
git merge --no-ff $(git merge-base A C)
git checkout A
git diff bPlusC..HEAD

Answer 2

(Posting an option which doesn't completely answer my question, but which I puzzled out during my research.)

One possibility is to use the -p (patch) option of git log , which can take multiple branch labels for both inclusion and exclusion:

git log -p branch_A ^branch_B ^branch_C

This doesn't give a single summary of changes like git diff would, though, instead giving the separate changes for each commit included in branch A but not in branches B or C.

While less than ideal for getting an overall picture of the changes introduced by branch A, this commit-by-commit summary might be more useful when you're trying to cherry-pick changes from branch A.