How to pause/resume repository cloning in mercurial? - mercurial

I've recently needed to clone into development tree of some large projects (e.g. https://hg.mozilla.org/mozilla-central), but the problem is I'm on an slow unstable connection and thus I may not clone into the repository in a single pass.
Is it possible to pause/resume the cloning process somehow?

To clone a large repository in multiple passes, you can use the --rev option on the clone command. For example:
hg clone --rev 100 <remote URL> <local path>
cd <local path>
hg pull --rev 200
hg pull --rev 300
etc
See this related SO question.

Related

How to view diff between head of local repository and head of remote repository?

Before I push to a remote repository, I want to see a consolidated diff between the head of my local repository and the head of the repository I'm pushing too. The best way I know of doing this is to hg clone the remote repository, get the revision of the head, then do a diff between my head and that revision. But this is time-consuming. Is there a quick way?
In addition to
$ hg outgoing -p
which I normally use, I'll like to point you to revision sets. That is a query language that you can use with hg diff (and all other commands that lets you specify changesets). So you can implement hg outgoing -p by
$ hg log -r "outgoing()" -p
and you can get a diff between the parent of the first outgoing changeset and the last outgoing changeset with
$ hg diff -r "p1(first(outgoing()))" -r "last(outgoing())"
Finally, the remotebranch extension can maintain local information about the remote branches so that you don't need to use the network to lookup this information. It lets you use
$ hg log -r "not pushed()"
to find the outgoing changesets, but it's much faster since there's no network round trips involved.
If you're looking for a way of getting all the changes you've made that aren't in the remote repository.
$ hg outgoing -p
The -p is optional and reports in the form of a patch, otherwise it reports in the same way a hg log. This is just your changes regardless of whether anybody else has pushed anything to the remote repository.
If you're looking for changes in the remote repository that you don't have then you use
$ hg incoming
Again there's a -p form if you want it.
Neither of these are exactly what you asked for, but I suspect you don't actually want that.
If you really want the difference between your changes and the new head in the remote repo created by someone else, then you'll need to pull their changes over.
hg pull
hg heads # find revision number of new head
hg diff -r 124992 # or whatever the revision number is.

How to apply a collapsed revisions patch to trunk in Mercurial?

I am looking for best practices to do the following:
When I need to implement a feature or fix a bug, I am creating new Mercurial repository from the main one (a trunk).
Then, within some days, or weeks, I am implementing the task in newly created repository, making commits and periodically merging with trunk. After the code in new repository will pass all code reviews, I should provide a repository with all changes collapsed into single revision.
My common way to do this (rdiff extension should be enabled):
hg clone ~/repos/trunk ~/repos/new-collapsed
cd ~/repos/new-collapsed
hg diff ~/repos/new > new.diff
patch -p1 < new.diff
hg commit
This works almost well except when there are binary files present in the changes from ~/repos/new. Another way could be:
hg clone ~/repos/trunk ~/repos/new-collapsed
cd ~/repos/new-collapsed
hg pull ~/repos/new
hg update
hg rollback
then resolve possible conflicts and manually commit the changes
Both ways look for me somewhat ugly and non-native, so I am looking how this operation could be simplified. I've played with rebase extension, but seems its hg rebase --collapse command does not work with workflow described above.
Any ideas are welcome.
Sounds like a good case for mercurial queues.
I do something similar with the histedit extension.
My workflow is something like:
clone a central repo
commit incremental changes to local repo
clone my local repo to make collapsed repo
hg histedit and select/discard/fold the revisions as needed
hg push the collapsed repo to central repo
pull central repo to local or refresh local from scratch
I ensure that my local repo never gets pushed to the central repo by adding an invalid default-push path to the .hg/hgrc file in the local repo root directory.
Solved: Just add
[diff]
git = True
to your hgrc file, and then use my first solution with rdiff extension, replacing patch with hg import:
hg clone ~/repos/trunk ~/repos/new-collapsed
cd ~/repos/new-collapsed
hg diff ~/repos/new > new.diff
hg import new.diff
hg commit

Using Mercurial, how to diff with a fixed revision if commit intermediate states often?

Using Mercurial, say if I do an hg pull and hg up and now the local repo and working directory are both up to date.
What if I commit often, say 1 day later, and then 2 days later, and want to diff with the revision as of right now?
Otherwise, the diff is always comparing to the previous committed version.
I can use pencil and paper and write down the revision number right now, say, 4117, and then 1 day later, 2 days later, and any time before I am sure and push to the remote central repo, do an
hg vdiff -r 4117
(either using vdiff or diff). But instead of remembering this "magic number" 4117, is there a way to make Mercurial somehow remember this number? That way, hg vdiff is to see the difference between minor changes against committed code, but there is a diff that shows all changes before pushing to the remote repo.
(or, if there is command that shows the revision number since your last pull, which should also show 4117, so on bash we can do something like hg vdiff -r `hg --what-is-last-pull` )
Update: does hg out --patch show the diff of what would be pushed to the remote repo? If so, maybe it serves the purpose without caring the "magic number". But how to show the patch diff using kdiff3 or any other diff tools? Also, it seems we can do hg out and if we see 4118, 4119, 4120, then we know if we do hg vdiff -r ___ we should use (4118 - 1) which is 4117.
Update 2: actually, hg out --patch shows the diff between local repo and the remote repo, so it is close, but not exactly the same as the diff between working directory and the local or remote repo.
If you want to mark a revision you can use bookmarks extensions. It is shipped with mercurial. Documentationis available here
In your case,
hg pull -u
hg bookmarks lastpull
..hack..hack..
hg ci -m new-hack
hg diff -r lastpull:tip
hg bookmarks -d lastpull
Do it with multiple clones. When you clone from the remote repo initially use clone -U to create a clone that has no working directory files at all. Then clone again locally, for example:
$ hg clone my-local-clone-with-no-working-files my-working-clone
Do your commits and work in my-working-clone and then at any time you can check the tip in my-local-clone-with-no-working-files to see what the last thing you pulled from the server was. If you want to get fancy you could create a shell alias for:
hg diff -r $(hg -R $(hg root)/../my-local-clone-with-no-working-files id -i -r tip)
which will compare the working directory of the repo in which you run it (my-working-clone) with the tip of whatever you last pulled from the server.
It's worth nothing that this takes no extra disk space because local clones use hardlinks under the covers the the my-local-clone-with-no-working-files has no working directory files.
You can replace pen and paper with a local tag: hg tag -l -r <revision number on paper> tagname. Notice the -l, which makes the tag local, which means it does not get transferred by push and pull. You can also remove this tag by hg tag -l --remove tagname.

Can't branch a single file with Mercurial?

is this possible with Mercurial? and which Version Control system can do this besides Clearcase?
David is correct that you can't have a branch that exists on only a single file, but it's worth pointing out that people often have branches that alter only a single file. Since the branch metadata is stored in the changeset, and since the changeset contains only a delta (change), having a branch that alters only a single files is nearly instantanous to create, update, commit, and merge, plus it takes up almost no space on disk.
Resultingly, it's a very common way to handle per-customer configurations. Keep the tiny change for them in a branch, and merge from main, where development happened, into that branch, whenever you want to update their deployment.
How you could use MQ:
$ hg qnew -m "Changes for client0" client0
... change the file ...
$ hg qref # update the client0 patch with the changes
$ hg qpop # pop the changes off the queue stack
... develop like normal ...
... client0 asks for a build ...
$ hg qpu # apply client0's patch
$ make release
$ hg qpop
It would get a bit finicky if you've got to deal with a lot of clients… But it may be worth considering.
The other thing you could do, of course, is just commit a bunch of .diff files:
... make changes for client 0 ...
$ hg diff > client0.diff
$ hg revert --all
$ hg add client0.diff
$ hg ci -m "Adding client0 changes"
... develop ...
... client0 asks for a build ...
$ patch -p1 < client0.diff
$ make release
$ hg revert --all
No, it's not possible. A branch in Mercurial is a snapshot of the entire repository state.
You could do it with CVS, though, as CVS tracks changes on a per-file basis :)

mercurial: how to synchronize mq patches from a master repo as mq patches to a set of clone repos

I have to run a dozen of different build tests on a code base maintained in a mercurial repository. I don't want to run serially these tests on same repository because they modify a set of common files and I want to run them in parallel on different machines. Also, after all tests are run I want to have access to latest test results from those test work areas. Currently I'm cloning the master repository a dozen of times and run in each clone one different test. Before each test execution I do a pull/update/purge preparation sequence in order to start the test on latest clean state. That's good for me.
I'm also preparing new changes using mq extension that I would test on all clones as above before committing them. For testing some ready candidate mq patches I want somehow to deploy/synchronize them to be available in test clones and apply those ready for testing using some guard before running the test.
Did anybody do this synchronization before? What's the most simple way to do it? Do I need to have versioned mq patches for that?
patches can be maintained in their own repository provided you passed the "-c" switch to qinit like so
hg qinit -c
You may still be able to create a patch repo after the fact via
cd .hg/patches
hg init
hg addremove
hg commit -m "my patches"
But I haven't ever tried that personally.
then .hg/patches can be treated like any other mercurial repository. so I think you could probably roll some shell scripting. to get into the .hg dir of your cloned repos and do a
hg clone http://centralrepo.com/patch_repo ./patches
Here is the solution that I've implemented. Few notes:
all patches guarded with ready_for_testing AND those unguarded are applied for testing.
using versioned repos is better because we can make abstraction of queue repository implementation
I use mercurial 1.5.1
master repo is in master dir
clone repos are in clone-x dirs
Here are the steps (some could be optional):
once: put patches in master repository under versioning using mercurial:
a. hg -R master init --mq #no commit happen here, can be done later
b. hg -R master commit --mq --addremove --message 'initial patch queue' #make them visible to clone repos
for each clone, once after clone creation finishes: assuming no patches created yet on clones, initialize mq sub-repository:
a. hg clone master\.hg\patches clone-x\.hg\patches
b. hg -R clone-x qselect ready_for_testing
for each change ready in master (patch created/imported in mq repo): do this before launching tests for it:
a. review/update guards of mq patches: those included for testing should be unguarded or with +ready_for_testing
b. hg -R master commit --mq -A #make them visible to clone repos
for each clone, for each [test] iteration for each clone: do this preparation sequence before running the actual test:
a. hg -R clone-x qpop --all --force
b. hg -R clone-x pull
c. hg -R clone-x update --clean
d. hg -R clone-x purge --all
e. hg -R clone-x pull --mq
f. hg -R clone-x update --mq
g. hg -R clone-x qpush --all
As of Mercurial version 1.5, you can create a patch queue repository in an already existing Mercurial repo using the following command:
hg init --mq
It is OK to have queued patches when you issue that command.