Mercurial: Pulling in others merges + branching - mercurial

I'm still very new to Mercurial so please let me know what I'm doing wrong.
We have an hg repo for each of our developers. I'm working on a new feature in branch x. Since then, others have made critical changes to the project, which I have pulled into my repo. However, when I'm working on branch x my working copy still has the old stuff, which causes it to not play well w/ our shared MySQL database.
Q: How do I update my branch to have the other developers new stuff while keeping my own code in the x branch; I'm not ready for them to have it yet and I definitely don't want to merge x into default... I'm not sure what to do here...
Or am I going about this the entirely wrong way? If so, what should I be doing instead?
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Also, I'm using TortoiseHG, so if you have any instructions specific for that it would be appreciated.
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You are doing everything right. In order to "keep up" with the work of the other developers, you have to merge the default branch into your x branch. Not the other way around.
When you are in your x branch, it is as easy as doing hg merge default.
Edit : I deleted my statement about hg merge being equivalent to hg merge default, which is false. I misread the documentation.

Related

How to revert a file to an earlier version in Mercurial?

I made some changes to a file and committed it. (In fact there were several commits).
Then I wanted to revert to the earlier version and lose all those changes.
I did something like:
hg update -r nnn where nnn was the reversion number of the changeset I wanted to go back to.
That worked. I was happy.
Then, later, I had to push my local repository to the remote. But when I did hg push I got a message about there being two heads on this branch and one of them not being known to the remote repositiory. It suggested I merge before pushing. (I think).
I googled this and found a page that suggested I do "hg merge". I did that. Now the resultant file is back to where I started. I.e. it contains all the changes I wanted to throw away.
Where did i go wrong?
EDIT:
I have found this post Mercurial — revert back to old version and continue from there
where it says:
If later you commit, you will effectively create a new branch. Then
you might continue working only on this branch or eventually merge the
existing one into it.
That sounds like my case. Something went wrong at the merging stage it seems. Was I on the wrong branch when I did "hg merge"?
You're past this point now but if it happens again, and it's just a single file you want to revert then consider:
hg revert --rev REVISION_YOU_LIKED path/to/just/one/file.txt
That doesn't update you whole repository to a different revision, and it doesn't create any commits. It just takes a single file in your working directory and makes it look like it used to. After doing that you can just commit and you're set.
That's not the way to go if you want to undo all the changes you've made to all files, but for reverting a single file use revert and avoid multiple heads and merging entirely.
No, nothing went wrong at the merge stage – Mercurial did exactly what you asked it to...
What merge means is that you take the changes on your current branch, and the changes on the 'other' branch, and you merge them. Since your original changes were in the 'other' branch, Mercurial carefully merged them back into your current branch.
What you needed to do was to discard the 'other' branch. There are various ways of doing that. The Mercurial help pages discuss the various techniques, but there are pointers in other SO questions: see for example Discard a local branch in Mercurial before it is pushed and Remove experimental branch.
(Edit) Afterthought: the reason you got a warning about there being two heads on the branch is because having two heads is often a temporary situation, so pushing them to a remote repository is something you don't want to do accidentally. Resolutions are (i) you did mean to push them, so use --force to create two heads in the remote repository; (ii) ooops!, you meant to merge them before pushing, so do that; or (iii) ooops!, you'd abandoned the 'other' one, so get rid of it. Your case was (iii).

Mercurial: abandoning multiple, contiguous commits, on the `default` branch

Requirement
I'd like to abandon a line of development on the default branch, winding back to a revision from about 15 change sets back, and have default proceed from there.
My setup
This is a solo development project with one other guy testing infrequently. I push (frequently) to bitbucket for backups and sharing with the tester. Several of the changes I want to abandon are pushed to BitBucket.
Options
Any of these would be fine…
The abandoned change sets to continue to exist in the repo. It would be nice if they could live on their own branch abandoned-experiment-1, say, that I can close and ignore, but this would need them to move on to a retrospectively created branch (which seems like it would be an awesome feature?).
Some kind of merge to happen where I add a new revision to default that is the rollback to the revision I want to continue from.
The change sets to be destroyed, but I suspect there's no way to achieve that without replacing the BitBucket repo and my tester's repo, which I'm not keen on.
I'm not too sure how to evaluate which options are possible, which is best, or whether there are other, better options. I'm also not sure how to actually proceed with the repo update!
Thank you.
You do have several options (Note that I'm assuming that you are dispensing with all changes in the 15 or so revisions and not trying to keep small bits of them):
Easiest is kinda #2: You can close anonymous branches just like named branches; Tag the tip first with abandoned-development if you wish; hg update to the point you wish to continue from; and continue to code as normal. (You may need to create the new head for new development before you can close the old one. I haven't tested it yet.)
Regarding #3: Based on my cursory read, it does appear that bitbucket has a strip command. If you (both locally and on bitbucket) and your tester strip the offending changesets, you can carry on your merry way and pretend like they never existed.
Achieving #1: If you are definitely set on getting them to a named branch, you could strip them at the remote repos and then hg rebase them onto a new branch locally and then close that branch.
Personally, I try not to mess with history when I can avoid it, so I'd go with the easiest.
Mercurial now has (yet experimental) support for changeset evolution. That is you are able to abandon or rebase already pushed changesets. Internally this works by hiding obsolete changesets (i.e. practically nothing is stripped, only new replacement revisions are added to the history, that is why it works across multiple clones).
To extend #Edward's suggestions, you could also update to the last good revision, continue to commit from there and then merge in the head of the bad changesets using a null-merge:
hg up <good-revision>
... work ... commit ...
hg merge <head-of-bad-revisions>
hg revert --all -r .
hg commit -m 'null-merge of abandoned changesets'
This may be what you thought of as option 2.

Can I checkout & commit to several Mercurial hg branches at once?

I've forked a project from the internet, and I want to write some new features. I want to write several orthogonal features at the same time, (eg. debug helpers, new feature X, new feature Y), and have the code for all of them in my current directory, but when I commit, I want to be able to say "these files go to branch 'debug'", "those files go to branch 'feature X'", etc. Where these are branches in the 'hg branches' sense.
The reason for this is the project upstream may not want to merge my debug helpers or hacked bug fixes, but I certainly want to use them whilst developing my features.
Effectively, I just want to apply the changes in those files to the branch, but keep several branches checked out & merged to my current working directory.
Is this possible? Perhaps there's some hg extension to do this?
Thanks!
Look at mercurial queues (MQ) for things like debug helpers or local hacks. Very useful for patches that you only want locally and may want to apply to any revision/branch.
Doing the same thing with branches becomes tedious IMHO as you have to be very careful to do the changes for debug and features on different branches, and then merge them in to a local, throwaway branch in order to run anything. You can end up with lots of changesets on the feature branch that leave the tree in a broken state because you can only test after you commit.
I don't fully understand why you'd you would want to do things that way. If your features are orthogonal, you can work on them independently until they are ready to be merged. That is exactly what branches are for after all!
But to answer your question: you could commit on a branch and then, as a matter of workflow, always up to default and merge it in. That would keep the default branch as the sum of the other features. You would need to update to the feature branch before you commit, though and that could get tedious.
The other option for post-facto determining which branch you want to commit to is to use the rebase extension. In this case, you'd commit your changes and then do hg rebase -d targetBranch.
I don't recommend using history revisions as part of your standard workflow, though. That smells to me.

HG: How to push some (but not all) changes to 'stable' branch?

Say I do my new feature development either in default, or an entirely new branch made just for the feature for a web site project. When it comes time to push the feature out to the live website, I want to move it to the live branch, which I then hg archive to my apache directory.
Throughout everything, I want to be absolutely sure not to push other, unrelated changes that are not yet ready to be published to the live branch.
Is this even a good idea? Or should I be doing something entirely different?
If the code is in default, how do I push only the one thing I need and not everything to live? If I push just the latest changeset, is it smart enough to send the latest version of those files, or will it only do the changesets?
If the code is in an entirely new branch, do I merge the whole branch into live? How do I get those changes back to my default branch so I see them there too?
I was reading the "Task Based Management" section of the Mercurial Kick Start guide and it mentions merging default into your branch. I found this very confusing and was wondering why you'd ever do this.
Thanks for any help you guys can provide.
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I'm using TortoiseHG BTW
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HG now has Phases. Change a phase of a changeset to secret and it will not be pushed when you use push. You can do it using TortoiseHG GUI.
In addition to that, be aware that just pushing or pulling something does not automatically change any files in the working directory. It only makes some additional changesets available. Only by using update do you actually change any files in your working dir. (unless you configure hg to update automatically).
In the example you linked, there is a bug fix in the default branch. Bob wants to have this fix in his branch too, so he merges default branch with his branch. This is just an example to see how branching works. You do not have to use it in exactly the same way. If you just begin your Mercurial adventure, then you should better use just one branch until you have a good reason to use more.
For example: 3 developers work on the same project and all of them use just one branch (default). 1 of the developers wants to do a major refactoring of the code. He wants to commit several very unstable changesets (many "in the middle of work"). Doing so in the default branch might upset other developers. That is a good reason to create a branch. After his version is stable enough he will merge his branch into default. While he is doing development in his branch, he wants to be up-to-date with other developers, so he frequently merges default into his branch. Staying in a separate branch for too long might result in difficult merges. Luckily merging is very quick in HG, so merge often.

How do I permanently remove (obliterate) files from history?

I commited (not pushed) a lot of files locally (including binary files removing & adding...) and now when I try to push it takes a lot of time. Actually I messed up my local repo history.
How could I avoid this mistake in the future ? Can I transform a set of local revision 1->2->3->4 to 1->2 with 2 being the final revision of the local clone ?
edit: since I was in hurry I started a new remote repo from scratch with revision 4. In the future I will go with the marked answer as it seems easier but I will dig other solutions to see the truth. Thx for your support.
It's not clear from your question whether those changes got pushed. If they're still local, you can more or less get rid of them easily. convert is one option. You can also use MQ (mercurial queues). Check the EditingHistory wiki article for a detailed explanation. It recommends MQ being the simplest approach.
To prevent that kind of mistakes, you should probably add a hook to reject 'bad' commits, given that you can describe them programatically ;)
Mercurial history is immutable, you can't delete using the normal tools. You can, however, create a new repo without those files:
$ hg clone -r 1 repo-with-too-much new-repo
that takes only revisions zero and one from the old repo and puts them into a new repo. Now copy the files from revision four into the new repo and commit.
This gets rid of those interstitial changesets, but any repo you have out there in the wild still has them, so when you pull you'll get them back.
In general once you've pushed a changeset it's out there and unless you can get everyone with a clone to delete it and reclone you're out of luck.