Merging two patches in Mercurial - mercurial

I have two patches that I'd like to merge in mercurial. Sadly, I deleted the branch from which I exported these patches. Can you guys please suggest a way to merge the two patches?
I am using Mercurial 2.0.2 on a ubuntu 12.04 box.

If you have MQ enabled, and assuming you start with an empty patch queue:
> hg qimport patch1 # Import & apply the first patch into a patch queue
> hg qimport patch2 # Import & apply the second patch into a patch queue
> hg qpop; # Pop the second patch (unapply)
> hg qfold patch2 # Fold the second patch into the first (result is called 'patch1')
> hg qexport > new_merged_patch
You can then either:
> hg qfinish -a # Convert the currently applied patches (e.g. patch1) to changesets)
or:
> hg qpop # Pop the merged patch
> hg qdel patch1 # Delete it from the queue
To be honest, using MQ for this is overkill, but it's a useful extension to know.

If you have the patches as patch files you can just apply them on top of each other and generate a patch based on the result:
$ patch -p0 < patch1
$ patch -p0 < patch2
$ hg diff > cumulative.patch
The patch level, -p0, may be different depending on how your patches are structured.

Related

How to undo "hg qnew"?

I issued hg qnew without realizing that it includes any outstanding changes into the patch. I'd like to back that out and pick only specific changes using hg qrecord. How can I undo qnew?
Your answer definitely works — with newer Mercurial's you can use hg strip --keep to avoid doing the import step:
$ hg strip --keep .
$ hg qdelete patch-name
The --keep flag makes strip ignore the working copy while working, that is, it deletes the commit (like hg qpop would do) but it doesn't undo the changes to the files. After stripping you still have the patch in your series (unapplied) and you can then delete it.
I've found an anwer here:
hg qpop
hg import --no-commit .hg/patches/patch-name
hg qdelete patch-name
Please add a better way, if you know.
Update: Based on Aldo's answer, there is another way:
hg qnew test
# We can undo the above qnew as:
hg qrefresh -X '*'
hg qpop -f
hg qdelete test
If you just want to undo the latest qnew retaining all your local changes, one option is:
qcrefresh 123
hg qpop -f
hg qdelete <name of the patch>
Notice that 123 is just a random string: you are telling mercurial to only include the (hopefully nonexistsnt) 123 file in the current patch.
Newer versions of Mercurial When you issue will issue a warning about the fact 123 file does not exist, but this is exactly what we want here.
If you want to retain some of the changes in the current path, you can use the qcrefresh command from the crecord extension, which allows to graphically select the changes to be included in the current patch. You need to download it from Bitbucket, extract the archive and configure it in .hgrc:
[extensions]
crecord = <path/to/crecord/package>

In Mercurial how do I extract a single file's changes from a Changeset to apply to another branch?

I have a large commit of many files on one branch, I need to transfer the modifications of a single file in that changeset to another branch. How can I do this? I am mostly using TortoiseHg but commandline solutions are also fine.
If I go to the changeset in TortoiseHg and select the file I can see the diffs I want to transfer, but not a way to actually apply them.
You can get the patch for just that file using:
hg log -r THEREVISIONWITHLOTSOFCHANGES -p -I path/to/justthatfile > justthatfile.patch
which you can then import on whatever branch you want by doing:
hg update anotherbranch
hg import --no-commit justthatfile.patch
hg commit
The most basic solution is to dump the patch of the file, apply it to the current working revision, and commit it (assuming you're at the root of the repository):
$ hg up <revision-to-apply-the-patch-to>
$ hg diff -c <revision-containing-the-patch> <files-to-include> | patch -p0
$ hg ci -m "Transplanting selected changes from <revision-contain...>"
The drawback of this method is that it isn't very obvious what you've done from a revision history perspective. A good commit message helps here, but the history graph gives no hint about the process of transplanting some changes. In that case merging and reverting may be a better solution:
$ hg up <revision-to-apply-the-patch-to>
$ hg merge -r <revision-containing-the-patch>
$ hg revert --no-backup <files-to-exclude>
$ hg ci -m "Merge in changes of <files-to-include>"
Probably there are more solutions to do this -- these two came to my mind first.

mercurial push certain revision

I have searched here, but haven't found any question related to this. I got a problem like this in mercurial:
I manage open source project in bitbucket, so i have clone of the source code in my local. But I also using that project for my own live site, so I made 2 clone of bitbucket repo
Bitbucket Repo
|
==local_clone1
|
==local_clone2-> commit1 => commit2 => commit3
(personalization) (bug fix) (add feature)
The question is, I want to push commit2 and commit3 back to local_clone1, so later on I can push to Bitbucket repo. But don't want to push commit1, since it has my personal data.
Wondering how we do that in mercurial?
This can be done without too much difficulty in this case. See Removing history in the Mercurial guide for more information.
Here's the basics of what you'll need to do:
Go to local_clone2
Get the revision number (hg tip will show you) from the current number. We'll call it 731.
hg export 730-731 > ../local_clone1/changes.diff (or wherever you like)
Go to local_clone1
hg import changes.diff
You may need to edit things manually; refer to that guide for more info in that case.
Here are a couple of options:
backout
Given a history constructed as:
hg init db
cd db
echo >file1
hg ci -Am clone # rev 0
echo >file2
hg ci -Am personalization # rev 1
echo >file3
hg ci -Am bugfix # rev 2
echo >file4
hg ci -Am feature # rev 3 <tip>
Then if the current working directory is the tip, the following commands will "undo" the personalization revision:
hg backout 1
hg ci -m backout
The advantage is history remains immutable, but shows the addition and backout of the personalization changeset.
Mercurial Queues
With the mq extension, history can be edited to remove a changeset:
hg qimport -r 1:3 # convert changesets 1-3 to patches
hg qpop -a # remove all patches (can't delete an applied patch)
hg qdel 1.diff # delete rev 1's patch
hg qpush -a # reapply remaining patches
hg qfin -a # convert all applied patches back to changesets.
The advantage is the personalization changeset disappears. The disadvantage is the changeset hashes change due to the history edit, so this should never be done to changesets that have already been pushed to others. There is also the risk of a mistake editing history.

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 :)

How to move some changeset to a new branch in mercurial

I want to move a changeset from one branch to another. Basically, I currently have:
A -> B -> C -> D # default branch
And I want:
A # default branch
\-> B -> C -> D # some_new_branch
Where some_new_branch does not exist yet. I am used to git, so I guess there is a simple "mercurial" way I am missing.
One way is to export a patch for B,C,D; update to A; branch; apply patch:
hg export -o patch B C D
hg update A
hg branch branchname
hg import patch
To remove B,C,D from the default branch, use the mq extension's strip command.
Sounds a bit like a cherry-pick operation in git. The Transplant Extension may be what you're looking for.
With Mercurial Queue:
# mark revisions as draft in case they were already shared
#hg phase --draft --force B:D
# make changesets a patch queue commits
# (patches are stored .hg/patches)
hg qimport -r B:D
# pop changesets from current branch
hg qpop -a
#
hg branch some_new_branch
# push changesets to new branch
hg qpush -a
# and make them commits
hg qfinish -a
Without comments:
hg qimport -r B:D
hg qpop -a
hg branch some_new_branch
hg qpush -a
hg qfinish -a
Alternative to transplant or patch, you could use graft.
hg update A
hg branch branchname
hg graft -D "B:D"
hg strip B
Note that changing history is bad practice. You should strip only if you haven't pushed yet. Otherwise, you could still backout your changes.