What's the best three-way merge tool?

Question

Subversion, Git, Mercurial and others support three-way merges (combining mine, theirs, and the "base" revision) and support graphical tools to resolve conflicts.

What tool do you use? Windows, OSX, Linux, free or commercial, you name it.

Here's a few that I've used or heard of, just to get the conversation started: kdiff3, DiffMerge, P4Merge, Meld, Beyond Compare Pro.

(I recognize that this is sort of like the Best Diff Tool but it's different in that I explicitly focus on three-way merge tools; WinMerge is off the list, for example.)

Answer 1

Beyond Compare 3 supports 3-way merging, and is a pretty impressive merge tool. It's Commercial (but worth it, imho) and is available on both Windows and Linux.

As pointed out in a comment, it's also inexpensive.

Answer 2

Ultracompare, really good and handles large files (1G+) well, windows only, its commercial but worth it.

Answer 3

vimdiff. It's great. All you need is a window three feet wide.

Answer 4

xxdiff if you're in linux land.

Answer 5

Meld Diff Viewer

I have had only good experiences working with Meld. I use it when I have to do messy code merges between branches. It is simple to use and has a clean interface. It however may not be what you are looking for if you are locked into a windows environment.

• Open Source
• Linux and MacOS Supported
• Multiple File Diff
• Three-way Compare Support

In Ubuntu, install is as simple as: sudo apt-get install meld

Answer 6

I love ediff, standard in emacs.

Answer 7

Araxis Merge. Commerical, but so worth it... available for Windows and the Mac

Answer 8

TortoiseSVN comes with TortoiseMerge which can be very handy if you don't want to install/configure additional tools. It isn't as easy to use as TortoiseSVN itself though. Well after getting used to it, it's really a good tool.

Answer 9

Diffuse is an easy to use three-way merge tool. It supports all of the platforms and version control systems you mentioned.

Answer 10

I would like to add that you can also get BeyondCompare 3 Pro for Linux (not just windows). I hope that they release an OS X version in the future.

Answer 11

Just checked out P4merge since I heard about it in another blog article:

Very slick interface, and FREE! I've been a faithful Araxis Merge user, but considering this is free and awesome, I'd encourage you to check it out.

Answer 12

I use KDiff3 open source, cross platform

Answer 13

See also 3-way XML merge algorithm where I ask about 3-way merge of XML or HTML files.

Answer 14

Kdiff3 algorithm is really impressive.

Even when subversion indicates a conflict, Kdiff3 solves it automatically. There's versions for Windows and Linux. It is possible to integrate it with TortoiseSVN and with your linux shell.

It is one of my favorites open source softwares.

My only annoyance is that it is a little difficult to compile if it doesn't exist in your favorite disto repository.