I have recently cloned an HG repository into another one, since the project had to be slightly changed and i couldn't keep it with the other codebase.
Some changes though are common, and so needed to be updated in the older repository as well.
How can this be done?
I'd like to know more specifically:
Are changes that are not group together in a commit (sporadic changes i've made to code files) can be somehow grouped together and updated in the 1st repository (the one i cloned from).
If not, how can this be done if i make all changes grouped in the same commit?
Other recommendations for strategies for handling such cases will be great!
Thanks
What problem are you seeing exactly? What have you tried?
Can you clarify the issue, it seems like you are just looking for a way to pull from another repo, in which case:
hg pull -r {RevisionYouWantFromOtherRepo} {pathToSecondRepository}
Related
The project I'm working on using a lot of branches. I know there's been some changes to a particular file that I need on another branch, but I don't know what branch they were done on.
How can I find all changes done to a specific file, searching across all [named] branches?
I'm not sure if I'm misunderstanding the question, but hg log <filename> shows all changesets that include changes to a file, no matter what (named or unnamed) branch they're on.
I've struggled to understand how branching is beneficial. I can't push to a repo with 2 heads, or 2 branches... so why would I ever need/use them?
First of all, you can push even with two heads, but since you probably don't want to do that, the default behavior is to prevent you from doing it. You can, however, force the push to go through.
Now, as for branching, let's take a simple scenario in a non-distributed version control system, like Subversion.
Let's assume you have a colleague that is working in the same project as you. The current latest changeset in the Subversion repository is revision 100, you both update to this locally so that now both of you have the same files.
Ok, now your colleague has already been working on his changes for a couple of hours now, and so he commits. This brings the central repository up to revision 101. You're still on revision 100 locally, and you're still working on your changes.
At some point, you complete, and you want to commit, but Subversion won't let you. It says you have to update first, so you start the update process.
The update process wants to take your changes, and pretend you actually started with revision 101 instead of 100. If your changes are not in conflict with whatever it was your colleague committed, all is hunky dory, but if your changes are in conflict, you have a problem.
Now you have to merge your changes with his changes, and things can go haywire. For instance, you might end up merging one file OK, the second file OK, or so you think, and then the third file, and you suddenly discover that you've got some of the details wrong, it would've been better to merge the second file differently.
Unless you made a backup of your changes before updating, and sooner or later you will forget, you have a problem.
Now, the above scenario is actually quite common. Well, perhaps not the merging part, it depends on how many is working in the same area or files at the same time, but the "must update before committing" part is quite common with Subversion.
So how does Mercurial do it?
Well, Mercurial commits locally, it doesn't talk to any remote repository at all, so it won't stop you from committing.
So, let's try the above scenario again, just in Mercurial this time.
The tipmost changeset in the remote repository is revision 100. You both have cloned this down, and you're both starting to work on the changes, from revision 100.
Your colleague completes his changes and commits, locally. He then pushes his changeset up to the central repository, bringing the tip there up to revision 101.
You then complete your changes, and commit, also locally, and then you want to push, but you get the error message you've already discovered, and is asking about.
So how is this different?
Well, your changes are now committed, there is no way, unless you try really hard to accidentally lose them or destroy them.
Here's the 3 repositories in play and their current state:
Colleague ---98---99---100---A
Central ---98---99---100---A
You ---98---99---100---B
If you were to push, and was allowed to do this (or force the push through), the Central repository would look like this:
Central ---98---99---100---A
\
+--B
Two heads. If your colleague now pulled, which one should he continue working from? This question is the reason Mercurial will by default prevent you from causing this.
So instead you pull, and you get the above state in your own repository.
In other words, you can chose to impact your own repository and create multiple heads there, but you are not imposing that problem on anyone else.
You then merge, the same type of operation you had to do in Subversion, except your changeset is safe, it was committed, and you won't accidentally corrupt or destroy it. If, mid-merge, you want to start over, you can, nothing lost, no harm done.
After the merge, your local repository looks like this:
You ---98---99---100---A----M
\ /
+--B--+
This is now safe to push, and if your colleague now pulls, he knows that he has to continue from the M changeset, the one that merged his and your changes.
The above description is what happens due to Mercurials distributed nature.
You can also name branches, to make them more permanent. For instance, you might want to name a branch "stable", to signal that any changesets on that branch have been thoroughly tested and is safe for release to customers or to put into production. Then you would only merge changes onto that branch when said testing has been completed.
The nature, however, is the same as the above description. Whenever more than one person works on a project with Mercurial, you will get branches, and that's a good thing.
Whenever more than one clone of a repo is made and commits are made in those clones, branches happen, whether you name them by using the hg branch command or not. My philosophy is, you might as well give them a name. It makes things less confusing.
A good explanation of mercurial branches: http://stevelosh.com/blog/2009/08/a-guide-to-branching-in-mercurial/
The problem that I'm running into is that I have some code reviews to do, with ~10 commits per review. It's an active repo with constant commits from developers. I have TortoiseHg filtering my changesets so that I am looking only at the ones that I care about.
What I would like to see is the difference between the changeset before the first change, and the last (without all the non-related changesets showing). I simply want to see the final results of all these changes. I don't care that there was some horrible code in changeset 1, that was fixed in 3. I just want to see the diff of what ultimately got merged through all these changesets.
I feel like I'm missing the obvious, and this isn't a bright question. Nevertheless, I'm asking anyways. Anyone?
I'm not sure about 1.1.8, as I'm using the 1.9/2.0 candidate release, but I believe you could left-click on changeset1, right-click on revision3 and select visual Diff. This should open your diff tool of choice and only show you the diffs between the 2 versions.
When I did this in the newer tortoise, it opened BeyondCompare in directory compare mode, with revision1 on one side, and revision2 on the other.
Don't merge in between commits and diff off the developers clone between start and finish changesets.
Or If merges occured, update and merge everything and then take the entire codebase (or just changed files) and dump it onto a clean tip clone (make sure you are working with the same version to avoid overwriting anything). Recommit all at once.
As a former user of Subversion, we've decide to move over to Mercurial for SCM and it is confusing us a little. Although Mercurial is a distributed SCM tool we are using a remote repo to keep changes we make backed up on a server but we are finding a few teething troubles.
For example, when two or three of us work on our local repo's, we commit then push to the remote repo, we find that a lot of heads(?) are created. This confused the hell out of us and we had to do some merging etc to sort it out.
What is the best way to avoid so many heads and to keep a remote repo in sync with a number of developers?
Today, i've been working like this:
Change a File.
Pull from remote repo.
Update local working copy.
Merge? (why?)
Commit my changes to local repo.
Push to the remote repo.
Is this the best proceedure?
Although this has worked fine today, i can't help that feeling that i'm doing it wrong! To be honest i don't understand why merging even needs to be done at the pull stage because other people are working on different files?
Other than to tell me to RTFM have you any tips for using Mercurial is such a way? Any good online resources for information on why we get so many heads?
NOTE: I have read the manual but it doesn't really give much detail and i don't think i want to start another book at the minute.
You should definitely find some learning resources.
I can recommend the following:
hginit.com
Tekpub: Mercurial
As for your concrete question, "is this the best procedure", then I would have to say no.
Here's some tips.
First of all, you don't need to stay "in sync" with the central repository at all times. Instead, follow these guidelines:
Push from your local repository to the central one when you're happy with the changes you've committed. Remember, this can be several changesets
Pull if you need changes others have done right away, ie. there's a bugfix a colleague of yours has fixed, that you need, in order to continue with your own work.
Pull before push
Merge any extra heads you pulled down with your own changes, before you push, or continue working
In other words, here's a typical day.
You pull the latest changes when you come in in the morning, so that you got an up to date local clone. You might not always do this, if you're in the middle of bigger changes that you didn't finish yesterday.
Then you start working. You commit small changesets with isolated changes That isn't to say that you split up a larger bugfix into many smaller commits just because you modify multiple files, but try to avoid fixing more than one bug at a time, or implementing more than one feature at a time. Try to stay focused.
Then, when you're happy with all the changesets you've added locally, you decide to push to the server. When you try to do this, you get an abort message saying that extra heads would be pushed to the server, and this isn't allowed, so the push is aborted.
Instead you pull. This can always be done, but will of course now add extra heads in your local clone, instead of at the server.
Then you merge, the extra head that you got from the server, with your own head, the one that you created during the day by committing new changesets to your clone. You resolve any merge conflicts.
Then you push, and now it should succeed. On the off chance that someone has managed to push more changesets to the central repository while you were busy merging, you will get another abort and have to rinse and repeat.
The history will now show multiple parallel branches of development, but should always stay at max 1 head in your central repository. If, later on, you start using named branches, you can have 1 head per named branch, but try to avoid this until you get the hang of just the default branch.
As for why you need to merge? Well, Mercurial always work with revisions that are snapshots of the entire project, which means two branches, even though they contain changes to different files, are really considered two different versions of the entire project, and you need to tell Mercurial that it should combine them to get back to one version.
For one, you can pull at any time; pulling does just add changesets to your repo, but not change your local working files (except if you have enabed the post-pull update).
Merging is necessary if someone else has commited changes to the same branch you're currently working on. This created an implicit branch, and merging merely brings them back together. You can see this nicely with the "railroad track" in the repository view. Basically, as long as you don't merge, you stay on your own "private" track, and when you want to add your changes (can be any amount of changesets) you merge it back into the destination branch (typically "default"). It's painless - nothing like merging in older SVN versions!
So the workflow is not as rigid as you displayed it; it's more like this:
Pull as much as you like
Make changes and commit locally as often as you like
When your changes should be integrated, merge with the destination branch (can be a lower revision than the newest), commit and push
This workflow can be tuned somewhat, for instance by using named branches and sometimes by using rebase. However, you and your team should decide on the workflow to be used; Mercurial is quite flexible in this regard.
http://hginit.com has a good tutorial.
In particular, you'll find the list of steps you have here: http://hginit.com/02.html (at the bottom of the page)
The difference between those steps and yours is that you should commit after step 1. In fact you will typically commit several times on your local repository before moving onto the pull/merge/push step. You don't need to share every commit with the rest of developers right away. It'll often make sense to do several related changes and then push that whole thing.
I have a local mercurial repository with some site-specific changes in it. What I would like to do is set a couple files to be un-commitable so that they aren't automatically committed when I do an hg commit with no arguments.
Right now, I'm doing complicated things with mq and guards to achieve this, pushing and popping and selecting guards to prevent my changes (which are checked into an mq patch) from getting committed.
Is there an easier way to do this? I'm sick of reading the help for all the mq commands every time I want to commit a change that doesn't include my site-specific changes.
I would put those files in .hgignore and commit a "sample" form of those files so that they could be easily recreated for a new site when someone checks out your code.
I know that bazaar has shelve and unshelve commands to push and pop changes you don't want included in a commit. I think it's pretty likely that Mercurial has similar commands.
I'm curious why you can't have another repo checked out with those specific changes, and then transplant/pull/patch to it when you need to update stuff. Then you'd be primarily working from the original repo, and it's not like you'd be wasting space since hg uses links. I commonly have two+ versions checked out so I can work on a number of updates then merge them together.