Mercurial: enforce "hg pull -u" before "hg commit" - mercurial

I have in some cases a need to enforce that Mercurial-users have run hg pull -u before any hg commit can be allowed, i.e., hg pull will mean that the incoming queue is empty — and furthermore I also want that the person is using the head version of the branch.
How can I set up such a restriction?
(I am fully aware that this goes against parts of the DVCS design core)

You could ask your developers to install
[hooks]
pre-commit = hg pull -u
in their config files (it should probably be installed in the per-repository .hg/hgrc file since this workflow is repository specific).
This makes Mercurial a little Subversion-like: your developers will only have one outstanding changeset. But note as soon as someone pushes to the server, hg pull -u cannot update to the new branch tip since it will cross branches (topological branches) to do so. So a proper merge will be needed at that point (or a rebase, see hg pull --rebase).

Normally mercurial will NOT let you push an open head to the server without using the -f flag (force). You can write a hook to pull automatically but that can not be enforced server side due to the server not knowing what you have. There is an article on mercurial's website about this scenario:
https://www.mercurial-scm.org/wiki/TipsAndTricks?highlight=%28heads%29#Prevent_a_push_that_would_create_multiple_heads

As Adam says, perhaps what you really need to do is prevent multiple heads (per branch). This is what we do, using the 'forbid_2head' hook from Netbeans (linked from here https://www.mercurial-scm.org/wiki/TipsAndTricks#Prevent_a_push_that_would_create_multiple_heads)
The result is that the hook prevents any push that creates multiple heads on a branch (so one on the anonymous/default branch plus one each on named branches). This effectively forces a pull before commit because you have to pull, get the two heads locally, then merge or rebase to remove it.
note, the hook is on the server/master repo

Related

Safe way to purge history - Mercurial

I cloned a project to my local directory and made a lot of changes. My current goal is to push my changed code to a new branch in the remote repository. And eventually this new branch will be merged back to default.
My problem is, because of some stupid effort in the past a few weeks to try to recover some missing files, I end up with a few branch names that I don't want being shown in public.
Here's what I have:
$hg branches
dev-v02 197:xxxxx
dev2 194:xxxxx
dev 183:xxxxx
qa 189:xxxxx
$hg branch
dev-v02
My question is, if I push my current branch dev-v02 to the remote repository by "hg push --new-branch", and this branch later get merged back to default, will the unwanted branches show up in history of default? And if so, is there a safe way to purge them?
I do NOT want to discard my changes. I just don't want the unwanted branches showing up in "hg branches" or "hg his" commands by whoever later clones the project from the remote repository. I searched online and found "hg strip" but I couldn't tell from the article if it would also remove the changes I've made. Thanks.
Edit: I just cloned my local repository by "hg clone -r 197 original-dir dest-dir" as suggested by both kevin and chessbot and now hg branches shows:
dev-02 192:xxxxx
qa 187:xxxxx (inactive)
I guess "qa" remains because I had pushed it to the remote as a QA branch and closed it later, and I just have to live with that. I will push from this new directory from now on. Thanks guys for your help.
Try hg push --new-branch -b dev-v02 to specify that you're pushing only that branch.
(See: https://www.mercurial-scm.org/repo/hg/help/push)
Another thing you could do: Clone the repository locally on your machine, strip out the branches you don't want, and then push that clone to the server. Then you retain your history locally without pushing it to everyone else.
It depends.
Branches are permanently associated with a commit. The branch is part of the commit, and contributes to the hash. Changing the branch of a commit in the past would alter all commit hashes from that point forward. This is quite different from Git, where a branch is little more than an ephemeral pointer to a HEAD. Such pointers are implemented in Mercurial as bookmarks.
If the unwanted branches appear on commits which are (ancestors of) commits you want to publish, there is very little you can do, short of recreating the history with all-new hashes. This could (for instance) be done with hg export and hg import, along with local cloning and (probably) a certain amount of shell scripting. More efficiently, you could use the convert extension to automate the process. Since this changes commit hashes, it will likely cause serious problems if any of the commits have already been distributed publicly.
If you have no interest in sharing the offending commits, you can simply not publish them. This can be done with selective pushing. However, since you'll always have to manually exclude those commits every time you push, it's probably safer to clone and strip (or clone selectively with the -r flag). You can then push from your partial clone with impunity. Assuming you have a sufficiently recent version of Mercurial, you can also force the commits into the secret phase, so that they will not be pushed:
hg phase -fs revisions
You don't want to use hg strip, because it permanently removes the commits from the history (see Editing History in the Mercurial wiki)
If I were you, I would close the branches instead:
hg up -C badbranch
hg commit --close-branch -m 'close badbranch, this approach never worked'
hg up -C default
(source: Pruning branches in the Mercurial wiki)
After closing a branch, hg branches doesn't show it anymore.
If you do want to see closed branches, use the -c parameter:
hg branches -c
Disadvantage:
hg his still shows closed branches.
You could use the -b parameter though, to show only the default branch:
hg his -b default

Can I mark a branch as 'not going to push'?

I use named branches in Mercurial.
In doing so I have created one branch called playground where I can try out various wacky experiments. I never intend to merge this branch into any others and I never want to push it to our main repository.
Since creating it, every time I do a push I am told I have added a new branch and I have to use the --new-branch flag. At this point hg push -b default (or whatever branch I'm pushing) works fine but it's annoying. Is there any way to suppress that message by letting Hg know that I am not interested in pushing that branch ever?
Starting with Mercurial 2.1 (released in February 2012), you can mark your changesets secret to keep them from being pushed to another repository. You use the new hg phase command to do this:
$ hg phase --force --secret .
This mark the current working directory parent revision (.) as being in the secret phase. Secret changesets are local to your repository: they wont be pushed or pulled. Pushing now looks like this:
$ hg push
pushing to /home/mg/tmp/repo
searching for changes
no changes to push but 2 secret changesets
There is no equivalent mechanism in older versions of Mercurial. There your best bet is to create a local clone for the changesets you don't want to push.
Update:
Mercurial 2.1 introduced the hg phase command which allows users to control what change sets are exchanged with remote repositories. #MartinGeisler answer to this question details this method.
Original Answer:
If you want to create a local branch of your code you have a couple options. You can hg clone the repository which will locally create a branch of the entire repository in your filesystem. The other alternative is you can try to use a Mercurial extension like LocalbranchExtension.
There are many ways to branch in Mercurial without using a named branch. Just find a method that suits your needs.
Further reading: http://stevelosh.com/blog/2009/08/a-guide-to-branching-in-mercurial/
In addition to the excellent answer above concerning phases, you can also specify 'default-path' (in the [paths] section of your .hgrc) to refer to the local repository:
[paths]
default = ...
default-push = .
This will cause all outgoing changesets to be compared to the specified repository. In this case, comparing outgoing changesets in your local repository TO your local repository results in nothing to push.
You can still pull/update/merge from the main repository, but no push will ever send anything back to that main repository.
If you work on multiple machines/repositories, you can set one up as described above, and configure the others to specify the 'default' path to point to the server that pushes to itself. In this way, the other machines can push/pull to your local central repository, and these changesets will never escape your carefully configured collection of repositories.

Mercurial : hook to limit pulls to one branch only

I'm stumped trying to ensure that a deployment repository only updates a specific branch off the central Mercurial server.
Specifically I need to ensure that anyone pulling changes to the deployment repository is doing the equivalent of
hg pull -b deployment <central-repo-url>
rather than
hg pull <central-repo-url>
I assume I need to use the pre-pull hook, but I'm not sure how to do that.
Additionally, same technique, but more user-friendly way;
ACL extension, in which you define [acl.deny.branches] and [acl.allow.branches] for your workflow
The easiest thing might be to define an alias in that repository's hgrc that defines pull as pull -b deployment. Then, any attempt to pull will do what you want. However, it would be very easy to screw this up in such a way that would make any attempt to pull an infinite loop.
I would suggest a pretxnchangegroup hook. That lets you examine the changesets that are being imported, and reject them if you don't like them. I suspect that the rule you want to enforce is that the tip should always be on the deployment branch (the changegroup might drag in changesets from other branches which have been merged into deployment, but the tip should always come from deployment). That would be a hook like:
[hooks]
pretxncommit.deployment = hg log -r tip --template '{branch}\n' | grep '^deployment$'

How do you delete a commit in Mercurial?

I want to completely delete a Mercurial commit as if it was never entered in the repository and move back to my prior commit.
Is this possible?
If it was your last commit and you haven't pushed it anywhere, you can do that with rollback. Otherwise, no. Not really. Time to change your passwords.
Edit: It has been pointed out that you can clone from an older revision and merge in the changes you want to keep. That's also true, unless you have pushed it to a repo you don't control. Once you push, your data is very likely to be very hard to get back.
You can try to remove mq info about your commit.
For this you need to go File->Settings->Extensions.
There check mq and restart gui.
After that just right click on unneeded commit and
ModifyHistory->Strip
To edit the history I would use the Histedit Extension extension.
hg histedit 45:c3a3a271d11c
However keep in mind this only makes sense in a situation where you have not yet pushed the commits to the public repository, you own the public repository and/or you can account for all the clones out there. If you receive the following error:
abort: can't rebase immutable changeset 43ab8134e7af
It means that Mecurial thinks this is a public changeset (see phases) that has already been pushed - you can force it to be a draft again doing:
hg phase -f -d 45:c3a3a271d11c
I encounter this fairly often. I make a commit and then pull to push. But then there is something incoming that makes my newly made commit unnecessary. A plain hg rollback isn't enough because it only undoes the pull...
This is the thing to do:
hg strip <rev>
Things are painless when you don't push your changesets anywhere.
If it's more than one commit and/or you already pushed it somewhere else, you can clone your repository and specify the last changeset that should be cloned.
See my answer here how to do this:
Mercurial: Fix a borked history
If you only committed locally and didn't push, you can just create a clone locally (as described in my link) and you're done.
If you already pushed to some remote repository, you would have to replace that with your clone.
Of course it depends if you are able (or allowed) to do this.
You can use "hg backout" to do a reverse merge basically. All options are discussed in the freely available book "Mercurial: The Definitive Guide":
http://hgbook.red-bean.com/read/finding-and-fixing-mistakes.html
If using tortoise you can use modify history > strip...
Yes. Unless I am mistaken, as of v2.3 (rel. 2012/08/01) you can use the HisteditExtension with a drop command to drop a commit, along with strip or backout to remove changes.
A simple Google search on the feature: https://www.google.com/webhp#q=histedit+drop
In 2022 I do use evolve extension. It is one of the best extensions for this purpose.
To prune unwanted changeset, if you for example did a quick hack to get the code working:
$ echo 'debug hack' >> file1.c
$ hg commit -m 'debug hack'
Now you have a proper patch you can do hg prune .:
$ hg prune .
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
working directory is now at 2a39221aaebb
1 changesets pruned
If you push the change to the remote repository you will find only obsolescence markers:
$ hg push
searching for changes
no changes found
remote: 1 new obsolescence markers
To check the changes to your local repo you can pull from the remote one:
$ hg pull
pulling from ssh://userid#server/repo
searching for changes
no changes found

How to restrict "-f" option while making hg push

Is there any option to restrict a user to use hg push -f? Because it will remove intermediate commits by other users.
First of all, doing hg push -f cannot remove intermediate commits. Mercurial is built around an append-only history model and you cannot delete stuff from a server by pushing to it.
When a user does hg push -f, then he tells Mercurial to go ahead with the push even though it creates new remote heads. To prevent this, you need a hook on the server that forbids more than a single head. There are listed several such hooks here.
With Mercurial 1.6, it is no longer necessary to use -f when you push a new named branch. You should instead use hg push --new-branch. This is safer since it only allows the creation of new branches, not the creation of multiple remote heads.