What is the Difference Between Mercurial and Git?

Question

I've been using git for some time now on Windows (with msysGit) and I like the idea of distributed source control. Just recently I've been looking at Mercurial (hg) and it looks interesting. However, I can't wrap my head around the differences between hg and git.

Has anyone made a side-by-side comparison between git and hg? I'm interested to know what differs hg and git without having to jump into a fanboy discussion.

Answer 1

I think the best description about "Mercurial vs. Git" is:

"Git is Wesley Snipes. Mercurial is Denzel Washington"

Answer 2

They are almost identical. The most important difference, from my point of view (I mean, the reason that got me to choose one DVCS over the other) is how the two programs manage branches.

To start a new branch, with Mercurial, you simply clone the repository to another directory and start developing. Then, you pull and merge. With git, you have to explicitly give a name to the new topic branch you want to use, then you start coding using the same directory.

In short, each branch in Mercurial needs its own directory; in git you usually work in on single directory. Switching branches in Mercurial means changing directories; in git, it means asking git to change the directory's content with git checkout.

I'm honest: I don't know if it's possible to do the same with Mercurial, but since I usually work on web projects, using always the same directory with git seems much confortable to me, since I don't have to re-configure Apache and restart it and I don't mess my filesystem everytime I branch.

Edit: As Deestan noted, Hg has named branches, which can be stored in a single repository and allow the developer to switch branches within the same working copy. git branches are not exactly the same as Mercurial named branches, anyway: they are permanent and not throw away branches, like in git. That means that if you use a named branch for experimental tasks even if you decide to never merge it it will be stored in the repository. That's the reason why Hg encourages to use clones for experimental, short-running tasks and named branches for long-running tasks, like for release branches.

The reason why a lot of Hg users prefere clones over named branch is much more social or cultural than technical. For example, with last versions of Hg, it's even possible to close a named branch and recursively remove metadata from changesets.

On the other side, git invites to use "named branches" which are not permanent and are not stored as metadata on each changeset.

From my personal point of view, then, git's model is deeply linked to the concept of named branches and switch between a branch and another withing the same directory; hg can do the same with named branches, but yet it encourages the use of clones, which I personally don't like too much.

Answer 3

Git is a platform, Mercurial is “just” an application. Git is a versioned filesystem platform that happens to ship with a DVCS app in the box, but as normal for platform apps, it is more complex and has rougher edges than focused apps do. But this also means git’s VCS is immensely flexible, and there is a huge depth of non-source-control things you can do with git.

That is the essence of the difference.

Git is best understood from the ground up – from the repository format up. Scott Chacon’s Git Talk is an excellent primer for this. If you try to use git without knowing what’s happening under the hood, you’ll end up confused at some point (unless you stick to only very basic functionality). This may sound stupid when all you want is a DVCS for your daily programming routine, but the genius of git is that the repository format is actually very simple and you can understand git’s entire operation quite easily.

For some more technicality-oriented comparisons, the best articles I have personally seen are Dustin Sallings’:

• The Differences Between Mercurial and Git
• Reddit thread where git-experienced Dustin answers his own git neophyte questions

He has actually used both DVCSs extensively and understands them both well – and ended up preferring git.

Answer 4

Are there any Windows-based collaborators on your project?

Because if there are, the Git-for-Windows GUI seems awkward, difficult, unfriendly.

Mercurial-on-Windows, by contrast, is a no-brainer.

Answer 5

Sometime last year I evaluated both git and hg for my own use, and decided to go with hg. I felt it looked like a cleaner solution, and worked better on more platforms at the time. It was mostly a toss-up, though.

More recently, I started using git because of git-svn and the ability to act as a Subversion client. This won me over and I've now switched completely to git. I think it's got a slightly higher learning curve (especially if you need to poke around the insides), but it really is a great system. I'm going to go read those two comparison articles that John posted now.

Answer 6

If you are migrating from SVN, use Mercurial as its syntax is MUCH more understandable for SVN users. Other than that, you can't go wrong with either. But do check GIT tutorial and HGinit before selecting one of them.