How can I find all the commits that have more than one parent in a Git repository?

Question

I am working on a research to study merges in open source projects.

For each merge in the repo I need to find the base (nearest common ancestor), the two contributors, and the resulting merged commit.

I already have an idea of how to get the nearest common ancestor ( git merge-base rev1 rev2 ) and the contributors ( git log --pretty=%P -n 1 <commit> ), but I am having problem identifying the commits that resulted from a merge operation.

How can I find all the commits that have more than one parent in a Git repository?

Answer 1

This should be enough (for local commit)

 git rev-list --merges

The git rev-list man page mentions:

--merges

Print only merge commits . This is exactly the same as --min-parents=2 .

That means rev-list has some interesting filters:

--min-parents=<number>
--max-parents=<number>

Show only commits which have at least (or at most) that many commits.
In particular:

• --max-parents=1 is the same as --no-merges ,
• --min-parents=2 is the same as --merges .
• --max-parents=0 gives all root commits and
• --min-parents=3 all octopus merges .

Answer 2

Try:

git log --merges

with the appropriate --pretty to parse the output.