git - Find merge commit which include a specific commit

Question

Imagine the following history:

       c---e---g--- feature
      /         
-a---b---d---f---h--- master

How can I find when commit "c" has been merged into master (ie, find merge commit "h") ?

Answer 1

Add this to your ~/.gitconfig:

[alias]
    find-merge = "!sh -c 'commit=$0 && branch=${1:-HEAD} && (git rev-list $commit..$branch --ancestry-path | cat -n; git rev-list $commit..$branch --first-parent | cat -n) | sort -k2 -s | uniq -f1 -d | sort -n | tail -1 | cut -f2'"
    show-merge = "!sh -c 'merge=$(git find-merge $0 $1) && [ -n "$merge" ] && git show $merge'"

Then you can use the aliases like this:

# current branch
git find-merge <SHA-1>
# specify master
git find-merge <SHA-1> master

To see the merge commit's message and other details, use git show-merge with the same arguments.

(Based on Gauthier's answer. Thanks to Rosen Matev and javabrett for correcting a problem with sort.)