Git doesn’t come with a merge tool, but will gladly use third party tools…

The Git Debate

The reoccurring debate on switching from svn to git is going on again on the Ruby Core mailing list. Amoung the many objections to git is that it doesn’t come with a nice merge tool. Perforce was held up as an example of a tool that does merging right. Although I’m not a big fan of perforce in general, the merge tool in perforce was one of its two redeeming aspects.

Now You Can Have Your Cake and Eat it Too!

Although it is correct that git doesn’t come with a nice merge tool, it is quite happy to use any merge tool that you have on hand. And since Perforce’s merge tool is available free (from here), you can use p4merge with git.

Just add the following to your .gitconfig file in your home directory:

[merge]
    summary = true
    tool = "p4merge" 
[mergetool "p4merge"]
    cmd = /PATH/TO/p4merge \
            "$PWD/$BASE" \
                "$PWD/$LOCAL" \
                "$PWD/$REMOTE" \
                "$PWD/$MERGED" 
    keepBackup = false
        trustExitCode = false

Now, whenever git complains that a conflict must be resolved, just type:

   git mergetool

When you are done resolving the merge conflicts, save the result from p4merge and then quit the utility. If git has additional files that need conflict resolution, it will restart p4merge with the next file.

Enjoy.

Interested in (not) Hearing about Git?

I’m doing a talk that’s not about git at the Ohio, Indiana, Northern Kentucky PHP Users Group (yes indeed, that acronym is OINK-PUG) on September 17th. Although the talk is explicitly not about git, you will come away from the talk with a much deeper understanding on what goes on behind the curtains with using git.

If there are other local groups interested in not hearing about git, feel free to contact me.

Update (6/Sep/09)

Several people have mentioned that it is not obvious where to get the p4merge tool from the perforce page. Go to the Perforce downloads page and click on the proper platform choice under “The Perforce Visual Client” section. When you download “P4V: The Visual Client”, you will get both the P4V GUI application and the p4merge application.

Oops, Another Update (7/Sep/09)

I forgot that the shell script that runs p4merge is something you have to create yourself. Here’s mine:

#!/bin/sh
/Applications/p4merge.app/Contents/Resources/launchp4merge $*

There are more detais Andy McIntosh’s site