git 识别两个分支最近的交集

Question

是否有一个简写来标识两个分支共同的最后一次提交？例如，如果我有 master，然后 topic1 从 master 中分离出来，它们都继续

master:
a------b------c------d
        \
topic1:  r------s------t

Is there a way to identify say b?
For example if there was such a thing as master#topic1 (same as topic1#master) that meant, "the most recent commit shared by both master and topic."

I would like to be able to:

$ git checkout topic1
$ git diff master#topic1..topic1

我知道我能做到:

git diff master..topic

但我不关心提交 c 和 d。

Answer 1

使用git merge-base .

NAME
git-merge-base - Find as good common ancestors as possible for a merge

SYNOPSIS
git merge-base [-a|--all] [--octopus] <commit> <commit>…
git merge-base --independent <commit>…