Why do people like Mercurial branches? Was it revamped? I hate it when I used it.
By all means, I prefer Git branches.
By all means, I prefer Git branches.
Suppose I have a branch A with three commits, and then I make another branch B on top of that with another few commits. The Git model essentially says that B consists of all commits that are an ancestor of B that aren't the ancestor of any other branch. But now I go and rebase A somewhere else--and as a result, B suddenly grew several extra commits on its branch because those commits are no longer on branch A. If I want to rebase B on the new A, well, those duplicated commits will cause me some amount of pain, pain that would go away if only git could remember that some of those commits are really just the old version of A.
Not really. Git will recognize commits that produce an identical diff and skip them. Your only pain will be that for each skipped commit, you will see a notification line in the output of your `git rebase`:
warning: skipped previously applied commit <hash>And drawbacks, naturally. Advanced branching/merging workflows become extremely painful if not impossible, which makes mercurial unusable as a "true" DVCS (where everyone maintains a fork of the code and people trade PRs/merges).
How does it differ from an extra line on each commit message saying the branch name, and some options to parse it if desired?
I definitely get annoyed sometimes when I have to put in extra effort to figure out which side of the tree is which.
That's really, really not true. First off, I used the word "inherent", which doesn't mean "immutable"; you can retain all the benefits of mutability if you so desire. Of course, Mercurial historically focused a lot heavier on immutable commits than Git did, but hg eventually found a different path that really makes using git feel antediluvian in comparison.
The second thing to note is that there's no requirement that the 'branch' property of a commit correspond to only one head. Actually, I don't think any of the mercurial repositories I've contributed to ever bothered with branches; there's just simply no need in mercurial to create multiple named branches, the way there is in git.
Finally, mercurial solves the workflow problem in another way, by essentially realizing that there is a dichotomy between public, immutable commits and work-in-progress draft commits. The problem with PRs is that you end up in a situation where you have the unenviable choice between making updates with 'address fixes' commits that pollute history or rebases that risk making comments go into the ether (especially on GitHub). You might have extra squashes or rebases that make PRs that depend on other PRs painful. Mercurial instead makes a rebase or other history edit simply mark the old commit as dead and link to the new version, so that any other commits that depend on it can know how to be updated to the new version. And this information is spread to anyone who pulls from your repo, but need not be retained when pushed to anyone who didn't know about the old dead versions!
> The difference between git branches and named branches is not that important in a repo with 10 branches (no matter how big). But in the case of PyPy, we have at the moment 1840 branches. Most are closed by now, of course. But we would really like to retain (both now and in the future) the ability to look at a commit from the past, and know in which branch it was made. Please make sure you understand the difference between the Git and the Mercurial branches to realize that this is not always possible with Git— we looked hard, and there is no built-in way to get this workflow.
> Still not convinced? Consider this git repo with three commits: commit #2 with parent #1 and head of git branch “A”; commit #3 with also parent #1 but head of git branch “B”. When commit #1 was made, was it in the branch “A” or “B”? (It could also be yet another branch whose head was also moved forward, or even completely deleted.)
In this post they say that "Github notes solves much of point (1): the difficulty of discovering provenance of commits, although not entirely"
There is either base branch A whose current head is commit #2 / branch B with head of commit #3.
OR
Commit #1 is branch “default” commit #2 is branch “A” with parent as commit #1 and commit is branch “B” with parent also as commit #1
Consider your same example with forking instead of branching, how would the issue be resolved?
The question isn't how many branches, it's what branch the commit was on at the point in time it was created. That's not up to interpretation. It's information that was not recorded.
> Consider your same example with forking instead of branching, how would the issue be resolved?
Forked repositories don't have IDs, don't generally keep track of each other, and there's no way to even count them. So that's not solvable.
But branches do have names, and you almost always make commits onto branches. We shouldn't give up on tracking branches just because tracking forks is hard.