Is Git Irreplaceable? (2019)

I have never used Fossil, but I used to be a strong proponent of Mercurial. My advice is don't - Mercurial lost, git has won, and fighting against the current is just going to make your life harder.

The main advantage Mercurial has over git is a command line syntax that makes consistent sense. The operations you want to do are easy and as you try and do more complicated things, the new commands will be unsurprising and predictable. If you already know how to use git then this advantage is (mostly) irrelevant.

There are some other features that are interesting - Mercurial has a couple of different types of branches. Bookmarks are like git branches, whereas named branches are a completely different concept which can be useful. 'Phases' tracks whether commits have been shared, and prevents you rewriting (rebasing) them when appropriate.

If you do experiment, note that many 'power user' features are turned off by default. There is a robust extension system, and the default mercurial installation includes a load of standard ones. My config file includes the following to turn on some useful stuff ('record' is the most useful for a staging area like facility):

[extensions] pager = color = convert = fetch = graphlog = progress = record = rebase = purge =

I know Git inside and out, but I had to use Mercurial for a client a couple years ago. I found it to be the most baffling and nonsensical source control experience of my life. It might be a case of cross-contamination. Like you said, each SCM uses similar terms for different concepts, so my Git knowledge may have unfairly colored how I expected similar terms to work in Mercurial.

But stuff like: "hg log" gives you _every commit in the repo_?? When is that ever useful? How do I get only the commits that lead to the current state of the repo? Mercurial doesn't have branches; instead you're supposed to _copy the whole directory_[1] at the filesystem level?? Of course this is ridiculous, so they invented "bookmarks" which are actually Git branches. The extensions thing you mention is also a ridiculous chore. Just have sane defaults. I also found hg's output very dense and hard to understand and read, poorly suited for human consumption.

I dunno. I'm sure Mercurial is fine, many people use it every day, and likely my strong Git bias was affecting my ability to learn Mercurial. But I found it far easier to just clone into Git, use Git to do source control, and then export back to Mercurial when I'm ready to share my work.

[1] https://www.mercurial-scm.org/wiki/TutorialMerge

Mercurial does absolutely not require you copying at the fs level. You're not the first person to be caught out by that tutorial, which I think would serve us best by being deleted.

The 'original' branching method for Mercurial is called Named Branches. The big difference with Git is that every commit is labelled with what branch it is on. This has advantages - if you imagine looking at the train track of 'master' in git with it's divergence for a few commits and then merge, you can see that the 3 commits were on a branch called 'performance', whereas with git that history is completely lost. See: https://www.mercurial-scm.org/wiki/NamedBranches

As usage of git grew, the git branching model gained popularity and so the Mercurial bookmarks extension was created (https://www.mercurial-scm.org/wiki/Bookmarks).

It can be seen as a downside that there are two branching options that you have to choose between.

It's not just that tutorial, see also [1,2]. I think this is/was really an "official" way to do branching, and it seems utter madness to me :)

[1] Sadly the popular hginit.com seems dead, this was my first introduction to Mercurial. https://web.archive.org/web/20180722012242/http://hginit.com...

[2] https://stevelosh.com/blog/2009/08/a-guide-to-branching-in-m...

Branching by cloning was copied from bitkeeper. It was also early git's only branching mechanism. If you listen to Linus's talk when he introduced git at Google, you'll hear him conflate "branch" with "clone" because that's what he was thinking of at the time.

https://www.youtube.com/watch?v=4XpnKHJAok8

I associate that particular madness with Bazaar rather than Mercurial. It stopped being standard practice a while ago, and those old tutorials should be updated or removed.