this post was submitted on 11 Apr 2025
457 points (98.7% liked)
Programming
19578 readers
27 users here now
Welcome to the main community in programming.dev! Feel free to post anything relating to programming here!
Cross posting is strongly encouraged in the instance. If you feel your post or another person's post makes sense in another community cross post into it.
Hope you enjoy the instance!
Rules
Rules
- Follow the programming.dev instance rules
- Keep content related to programming in some way
- If you're posting long videos try to add in some form of tldr for those who don't want to watch videos
Wormhole
Follow the wormhole through a path of communities [email protected]
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
What do you mean by "are a thing?" Git has branches.
Git branches are very different to Mercurial branches. In git they're similar to tags that move along with the head commit of that particular branch. In Mercurial every commit contains meta data indicating the branch it's on. It also has a query language that lets you do sone quite neat things with selecting groups of commits based on their metadata, which can be useful in code reviews and similar.
That just sounds like an implementation detail.
Can you provide an example of something that's possible in Mercurial, but not git?
I've never used Mercurial, but a simple one based on the explanations and my experience with Git:
Locating the branch a commit originated from. If a git branch has been merged into (or rebased on) main or another branch, there's no way to tell which commit came from which branch. But sometimes I'd really like that information to figure out what prompted a certain change. Without it, I need to use external tools like a ticketing system and hope the other developers added in the necessary information.
That seems to be the opposite of useful if a commit is initially pushed to a development branch, which is relatively standard practice; now you're polluting the tree with data that's purposefully ephemeral, and even potentially leaking internal information.
Also, I'd argue that such deep details do belong in another tool, rather than asking the source control tool perform triple duty by being a CR and issue tracker as well.
Most of the time you're right, it's little more than a detail, but sometimes I miss the querying that it allowed. You could ask for things like a list of all branches that branched from a specific parent branch and modified a specific file, Which can be handy when you want to understand the impact a change might have before you make it and try merging.
Having the branch name embedded in the commit means you can meaningfully ask this sort of question. In git's model you can't say a changeset is in a specific branch once there are child branches further downstream because the changeset is in all of those branches.
Rather than come up with lots of examples for other queries (I know it wasn't the focus of your question, but I think it's really neat), I found this page which seems like a reasonable description.
No, git has labels on heads of branches. Once the head moves you loose the information. It also makes for a more messy history, which I believe created the whole "rebase everything" philosophy to cope.
What information is "loosed" when another commit is made to the branch?
If I hand you a commit, you cannot tell which ‘branch’ it is on without searching the git history and hoping that you only get one answer. That’s a bummer if, for instance, you’re a github action and only get handed the commit. If it’s on the master branch, I want to do different things than if it’s a dev branch.
A commit all by itself doesn't mean as much without context.
Why would I not want to be able to apply a commit to any arbitrary branch?
Also, GitHub is not git - it's based on git. Any shortcomings it may have aren't necessarily due to a flaw in git.
Luckily a commit points to its parent, which means the context is inherently present. What’s your point?
Nobody said that.
True enough.
Your claim appears to be that Mercurial binds commits to branches, and I'm explaining how I fail to see the advantage.
It makes the history clearer.
How is a Mercurial commit tree clearer than a git commit tree?
Branches are distinct.
Let's say you have a main and a dev branch, and you periodically merge dev into main. Because of fast forwarding (on by default) the main branch is completely gone from the history. If you then add bug fixes and project branches it becomes a tangled mess really quickly and it's nearly impossible to understand the structure by looking at the tree.
On mercurial every branch is named and distinct forever. You don't have to try to understand what happened to the project since it's obvious by looking at the tree.
Now there are ways to have a clean git history, but afaik you either need to make sure nobody ever messes it up or have everyone rebase everything and only keep the history of the main branch.
When working in a hyper structured organization that may work, but for more casual developers (scientists, students) that aren't system experts and where you have messy history, mercurial default settings are less confusing, easier to learn and produce better results.
No, merging in git does not make branches disappear.