Tool to see multiple Git Logs at once

Question

I am tasked with ensuring that our master branch is merged into our developer branches on a regular basis.

Our structure is like this. We have 4 repositories, in each of those repositories we have a main master branch, and about 5-10 developer branches that are being worked on at any given time. Developer branches can be active from between a day to 3 months, and the names of the branches are never duplicated.

Once a week, I need to check all the developer branches, as well as the master branch and keep track of which branches have been merged, and which ones have not been, and when their last merge took place.

I am currently doing this by using SmartGit and switching to a branch, and checking the log, etc, however I would like to make this process faster or even possibly automated.

Are there tools that do this, is there a bat script I can write to do this?

Looking at other git related questions, I see I can likely use some combination of

git show :/"Merge branch 'master'"

and

git log --pretty=format

But I must be missing something which will make this quicker and easier than the current manual method.

Edit:

The answer so far have been very promising, which makes me want to add in two wrinkles.

1. I need to keep track of both directions. When a developer branch merges from master, and when it merges to master.
2. We have a third branch which I also need to monitor called "production". Can the answers that compare master to other branches also work with comparing the "production" branch to the various named developer branches?

Answer 1

One simple workflow change would be to use the --all option to git log.

This cause log entries from all branches in the repository to be included in the log. Combining this with whatever other options you may want will reduce your log spelunking from ~30 (one per branch) to 4 (one per repository).

Depending on your needs, you may find these other options useful:

git log --all --graph --decorate

Some people also like to use --oneline, but I'm not crazy about it. I find the visualization easier to view without it, but experiment both ways.

You may also want to explore git log master..<branch-name>, which will show commits reachable from <branch-name> that are not reachable from master. This is effectively the list of commits you are looking for. This can probably be scripted to generate a list from each branch.

The accepted answer from this question goes into more detail about iterating through branches via a script using git for-each-ref.

Answer 2

Would these help you?

# view the branches that have been merged already
git branch --merged

# view the branches that have NOT been merged yet
git branch --no-merged

Answer 3

git log can be used to list commits that exist in one branch but not another one. For example,

git log developer..master

shows which commits have reached the master branch but not the developer branch and

git log master..developer

naturally does the opposite thing. You can combine this with the various formatting options to produce a report to your liking.

To find out when the developer branch was updated from the master branch you can use git merge-base which finds the most recent commit that's common to both branches. Note that such a commit might be on the developer branch if the most recent merge was from developer to master rather than the other way around, but if you only merge to master once (at the end of the developer branch's lifespan) this shouldn't be a problem.