Retroactive named branching in Mercurial - mercurial

Is there a way to associate a bunch of Mercurial changesets with a named branch after they have been committed, i.e. retroactively ?

I just wanted to do this, and here’s the solution I found.
A year has passed since the question was originally asked, this might explain why I can now find a solution.
It has the disadvantage that you create an extra revision in the process, but this wasn’t too bad for me.
First, you go back to where you want to create the branch.
In my case, I actually wanted to start a new root (because I wasn’t very sensible when I started the repository, but anyways), so I’m updating to null. You probably want to start somewhere else, it depends on your situation.
$ hg update null
Then, create the branch.
$ hg branch blah
$ hg commit -m "Created blah branch."
Then, we rebase all the commits we made onto our new branch:
$ hg rebase -s SOURCE -d DEST
The SOURCE here should be the first commit you made in the commits you want to create the branch from, and the DEST should be the commit where the branch was created (the one we committed above).

No, branch names are part of the changeset (it's really like a label you add to the commit), it means the changeset hash depens on the branch name.
So the only way to change it retroactively is by rewriting history (which doesn't play well if you pushed your changes elsewhere, since you'll have to rewrite every repo which has the changes).
To rewrite history, you could use for example mq.

Not a complete solution but, without re-writing history; you could tag the last change set in the unnamed branch. If you never rebranch from this the tag should surfice. If you do need to rebranch you can move on to a named branch after the tagged changeset.

Related

Duplicate a branch in Mercurial?

How can I duplicate a branch in Mercurial? I need the new branch to be against head (as the first one is).
The GIT equivalent (if I was in branch-a) would be:
git checkout -b branch-b
A Mercurial branch is a named entity that consists of all the commits contained within the branch. So in order to duplicate some existing branch, you must also duplicate all of its commits to new commits that are in the new branch. We then get into metaphysics arguments about commit identity. It's probably not a good idea to go here at all, but if you do want to go here, use hg graft to copy all the desired commits into the new branch.
A Git branch consists of a name containing a raw commit hash ID. So duplicating a Git branch under a new name is trivial. Note that the set of branches that contain any given commit changes dynamically over time: a branch that was only on feature/tall may now only be on master, even though that commit is still that commit, even via most of these metaphysical arguments. (Only the "no identity over time" argument lets us claim that this is not the same commit.)
Another way to put it is that Mercurial's branches actually mean something, but Git's don't. If you need true branches, you can't use Git in the first place. Don't try to import Git's bizzareness into Mercurial: you'll just make your own life miserable.
Meanwhile, though, Mercurial contains a DAG just like Git. If you use Mercurial bookmarks, those work like Git branches. It's probably wiser, then, to just use bookmarks and be done with it.
If all else fails, see hg graft.
the new branch to be against head
What is this (in usual business-term, not Git-lingua)? While in common (and in details) #torek is totally right, he forgot to write exact command-set, something like
hg up <rev-id>
hg branch <new-branch-name>
hg graft -r "branch(old-branch-name)" --log

How to clone from a specific revision to the last one using Mercurial?

In Mercurial , How to clone from a specific revision to the last one using ?
For example repo A have one line history from changeset 0 to changeset 100. and I want to clone A to my local repo from changeset 90 to last one (100).
Looking through the help, I noticed the -r flag but that only clone 1 specific changeset.
And if there is no way to do it can somebody explain why its not implemented ? its considered a bad thing to do ?
Thanks.
You can't.
The current state of the project is all changesets from the beginning of time up until the specific changeset, you cannot prune older changesets without rewriting the history of the repository to permanently get rid of them. This will also make the repository incompatible with the original that contains the old history.
In short, you will have to do one of the following:
Prune the old history, permanently getting rid of it, which will make it impossible to push/pull with original clones that still has that history
Live with the history
The parameters to the clone command that specifies revsets thus only allow you to set an upper limit. This may allow you to avoid whole branches, if they aren't merged into the branch you end up cloning, but the clone command will always clone everything from the beginning of time.
For every changeset you clone, every predecessor will be cloned as well, and this cannot be avoided.

How do I put a bunch of uncommitted changes aside while working on something else

If I have a bunch of uncommitted changes and want to set it aside while working on something else instead, and then later (f.i. after several days) come back to it and proceed working. What would be the easiest workflow to accomplish this? (So far I have only experience with Mercurial's basic functionality). My usual method was to create a new branch using clone, but there might be better ways.
You have a handful options:
Shelve the items. This saves the changes and removes them from the working directory so the branch can continue. It doesn't create a change-set.
hg shelve --all --name "UnfinishedChanges"
hg unshelve --name "UnfinishedChanges"
Update/Edit: Newer versions of mercurial may need to use
hg shelve -n "UnfinishedChanges"
hg unshelve "UnfinishedChanges"
You can still use --name as an alternative to -n, but mercurial doesn't seem to like --name anymore. Additionally, the --all is no longer required and mercurial will in fact freak out over it.
Patch queue the items using mq. This isn't too dissimilar to shelve in some respects, but behaves differently. The end result is the same, changes are removed and can be optionally re-applied later. When pushed, the patches are logical change-sets, when popped they are saved elsewhere and are not part of change-set history.
hg qnew "UnfinishedWork"
hg qrefresh
hg qpop
hg qpush "UnfinishedWork"
Commit them locally, update to the previous change-set and continue working and make use of anonymous branches (or multiple heads). If you then want the changes, you can merge heads. If you don't want the changes, you can strip the change-set.
hg commit -m"Commiting unfinished work in-line."
hg update -r<previous revision>
hg strip -r<revision of temporary commit>
Commit them to a named branch. The workflow then becomes the same as option 3 - merge or strip when you are ready.
hg branch "NewBranch"
hg commit -m"Commiting unfinished work to temporary named branch."
hg update <previous branch name>
Personally I use option 3 or 4 as I don't mind stripping change-sets or checking-in partial code (so long as that doesn't eventually get pushed). This can be used in conjunction with the new Phase stuff to hide your local change-sets from other users if need-be.
I also use the rebase command to move change-sets around to avoid merges where a merge wouldn't add anything to the history of the code. Merges I tend to save for activity between important branches (such as release branches), or activity from a longer-lived feature branch. There is also the histedit command I use for compressing change-sets where the "chattiness" of them reduces the value.
Patch queues are also a common mechanism for doing this, but they have stack semantics. You push and pop patches, but a patch that is "underneath" another patch in the stack requires that the one on top of it be pushed also.
Warning, as with all these options, if the files have more changes since the temporary changes that you've shelved / queued / branched, there will be merge resolution required when un-shelving / pushing / merging.
Personally, I don't like any of the answers posted so far:
I don't like clone branching because I like each project to have only one directory. Working on different directories at the same time completly messes the history of recent files of my editors. I always end up changing the wrong file. So I don't do that anymore.
I use shelve for quick fixes (just to move my uncommited changes to another branch, if I realize I'm at the wrong one). You are talking about days, no way I'd shelve something for days.
I think mq is too complicated for such an ordinary sittuation
I think the best way is to simply commit your changes, than you go back to the changeset before you start these changes and work from there. There are some minor issues, let me illustrate:
Let's say you have the changeset A. Than you start your changes. At this point you want set it aside for a while. First of all, commit your work:
hg ci -m "Working on new stuff"
If you want, you can add a bookmark to make it easier to come back later. I always create bookmarks to my anonymous branches.
hg bookmark new-stuff
Go back to the changeset before these modifications
hg update A
From here, you work and generate the changeset C. Now you have 2 heads (B and C), you'll be warned when you try to push. You can push only one branch by specifying the head of that branch:
hg push -r C
Or you can change the phase of the new-stuff branch to secret. Secret changesets won't be pushed.
hg phase -r new-stuff --secret --force
To keep local uncommited changes, easiest way for me is just to save them as a patch file.
hg diff > /tmp/`hg id -i`.patch
and when you need to return to previous state:
hg up <REV_WHERE_SAVED>
hg patch --no-commit /tmp/<REV_WHERE_SAVED>.patch
You can just clone your repo multiple times. I tend to have a root clone, then multiple childs from there. Example:
MyProject.Root
MyProject.BugFix1
MyProject.BugFix2
MyProject.FeatureChange1
MyProject.FeatureChange2
The 4 childs are all cloned from the root and push/pull to/from the root. The root then push/pulls from the master repo on the network/internet somewhere. The root acts as your sort of personal staging area.
So in your case, you'd just clone up a new repo and start working. Leave your 'shelved' work alone in the other repo. It's that simple.
The only downside is disk space usage, but if that were a concern you'd not be using DVCS at all anyway ;) Oh and it does kind of pollute your Visual Studio "recent projects" list, but what the hey.
[Edit following comments] :-
To conclude then... what you're doing is completely fine and normal. I would argue it is the best possible way to work when the following are true: 1) it is short-lived 2) you don't need to collaborate with other developers 3) the changes don't need to leave your PC until commit/push time.

Force pushing to new head when already pulled all changes

Is it possible to forcibly create new remote head when pushing ?
Suppose I have done some local commits on branch "default" then pulled and merged from remote.
Now, I would like to push my commits to remote creating new head and a bookmark but preserve existing remote head and tip - ie. my coworkers should not get my changes yet when doing hg fetch.
Basically this should be a short lived branch (thus not a named branch) for purpose of backup and code review by other before being fully merged into "main" head of default branch.
I've tried --new-branch but it didn't help - no new head was created and remote tip moved to my head.
You can use the --force option to force the creation of a new head.
The --new-branch option is used for named branch, in your case, we are talking of anonymous branching.
The reason why the "tip is moved" is because you merged the changeset recently pulled. Doing that, there's no way to do what you want.
You should just pull the new changes from the remote, and force push everything without merging, this will create a new head (called an anonymous branch), which can later be merged to the default branch by you or someone else after the code review.
You can also use a second repository to push your changes, but this is a totally different workflow.
You cannot preserve tip when you push: it is a pseudo-tag that always points to the newest changeset in a repository. The concept of tip is deprecated in Mercurial because tip can change meaning more or less randomly depending on the order of pushes — as you've seen.
The only way to create a new head is to, well, create it :-) By this I mean that you need two heads — one with your changes and one with the main code you want the colleges to pull and merge with. With only a single head (the one you got after running hg merge) there's no way to signal to the colleges that they shouldn't use it.
A much better approach is to use a separate repository on the server. Go to your repository management software and create a fork for your changes. Then push into that and tell your colleges to review it. They'll pull from your clone and look the changes over. If they like them, then they can merge with the main code and push to the normal repo. If they don't like the changes, then they can throw away their local clone, strip the changesets, or maybe just rollback the pull.
My solution to this issue is to use a previous revision for the start of the bookmark, if there is none or you just do not want to, you can make a dummy commit (like a small change to a README file, etc.) and bookmark the revision before that.
I think hg bookmarks need a lot of fine tuning before they become like git branches, but the process I describe is pretty much what is explained in the mercurial bookmarks kick starter.
For example, if your currently at revision 250.
echo >>README
hg ci -m "enabling bookmark branch_xyz"
hg book my-tip # optional but nice to have
hg book -r 250 branch_xyz
hg up branch_xyz
# hack ... hack hack
hg ci -m "awesome feature xyz (in progress)"
hg push -fB branch_xyz
now this bookmark lives on the server for others to work with ... but can be easily pruned later

Mercurial moving commits in another branch

My coworker accidentally made two commits in the default branch instead of creating new his own development branch.
How can I change this situation and moves these two commits to a new branch?
Imagine the following scenario:
D
|
C
| "I want to move C and D here"
B/
|
A
Steps:
hg update B
hg branch "mybranch"
hg commit --message "Create my branch"
hg update mybranch
hg graft -r C
hg graft -r D
hg strip -r C (this should be the revision C had originally)
The strip command is provided by an extension that you need to enable. You can follow a guide on how to enable it on the Mercurial Wiki.
hg update default
A major question
Have the accidental commits reached other repositories or is it just in his own? If so, you can skip to the section below 'Maybe the cat is still in the bag' otherwise you may have a fair bit of work to do.
You are not alone
See here for more discussion on how to correct the problem elsewhere on Stack Overflow. What is described is the 'proper' way to to it
export a patch
create the branch
import the patch
delete the earlier commits.
Maybe the cat is still in the bag
If the changes are only in the local copy, then a simpler solution is to
create the new branch
switch to it
merge the changes onto that either with your fav merge tool (go Meld) or with hg graft
use the hg strip command to delete the changes on the old brach
push the changes to the world
pretend like nothing ever happened, whistle a happy tune ...
The two answers above are both correct but, assuming one has not yet pushed the commits, there's a third way.
I just successfully used the rebase command to move a string of commits to a topic branch I had forgotten to create in the first place.
I first updated to the revision from which I wanted to create the branch on which my commmits were supposed to be, then I rebased the earliest of my commits from the wrong branch on this new one and ta-da, done.
Takes more time to explain it than to do it with TortoiseHg or even the command line, really.