How do I continue development from an earlier revision? - mercurial

In my project I would like to continue development from an earlier revision. So far I have done
$ hg up -r REV
and committed a changeset. How do I "get rid of" the old branch that I'm no longer interested in so I can push the repository without the force option?

To undo the last N commits (but without changing the history), do the following:
Revert the working directory to the desired revision:
$ hg revert -aC -r -<N + 1>
Commit the changes:
$ hg ci -m "Undo N changesets"
Now this branch can be merged with the other one.

Related

Replace master with a branch

I need to replace the contents of master with the contents of a branch. I can find details on how to do this in Git, but nothing for Mercurial.
Example Q for Git
Replacing master with another branch
My setup is
master
newbranch
I want the 'master' to be identical to 'newbranch
The basic choice you have is "rebase or merge": https://blog.sourcetreeapp.com/2012/08/21/merge-or-rebase/
Here on SO, a helpful Q&A is at:
Make another branch default?
The remainder of this response borrows from that page.
If you want to close the "feature-branch":
$ hg checkout default
$ hg merge feature-branch
$ hg commit
$ hg checkout feature-branch
$ hg commit --close-branch
The simplicity of the revert/commit approach mentioned there also has much to recommend it:
hg revert --all --rev ${1}
hg commit -m "Restoring branch ${1} as default"
where ${1} is (for example) the name of the relevant branch.
Doesn't the first approach assume there are no conflicts between the "default" and "feature branch"? When you desire to replace code, the assumption is that there ARE conflicts, and all should be resolved treating the "feature branch" as authoritative.

Diff after committing locally

I just cloned a repo from their remote.
I built the software, changed about 4 files, committed them locally and now want to create a patch that I can show them.
When I run :
hg diff -U8p abc efg pqr > patch_file
I don't see the changes I made. Does hg diff only compare the current files with the last committed files?
How do I get this to work?
To diff the working directory against a particular revision REV, use
hg diff -r REV
To compare two revisions against each other, use
hg diff -r REV1 -r REV2
To figure out which revisions to compare, examine the output of hg log. If you'll be doing this a lot and the base revision is fixed, give it a name (e.g., whatipulled) with
hg tag -r REV whatipulled
You can then specify whatipulled as the revision, instead of a numeric rev id (or a hash).
To export your diffs in a richer format, including commit comments etc., you can also use the following which is designed for this purpose:
hg export -r REV
There's also hg bundle -r REV, which produces a binary file with similar information.
But if you're sending changes back to the parent repo, the best method is to use hg push. It communicates your changesets directly to the parent; you don't even need to know which changesets need pushing. Of course, you must have the right to push to the parent repo.
hg push [ parent_repo_url ]
(If you pulled from it, mercurial should already know the path and you can leave it out).
If the parent repo is on bitbucket and you don't have pu, you can set up your own account on bitbucket, pull/push to that from your local repo, and then issue a "pull request" to the project repo, asking them to pull from you.
All of the above have options to control their behavior, which see.
From hg help diff
If only one revision is specified then that revision is compared to the working directory
In your diff for -r you must to use old tip (latest "not your" changeset) and update to tip (your latest changeset) before diffing.
If some binary data was modified in your changesets, don't forget to use -g option
hg up & hg diff -r <CSET> -g > some.patch
Improved diff for any active changeset and without hand-work for detecting base changeset (for linear history == in single branch)
hg diff -r "parent(min(outgoing()))" -r tip
By default, hg diff compares the currently checked out file with the last commit. You can change this by adding options:
-r REV compares the currently checked out files with a specific revision REV.
-c REV shows the changes made by revision REV
So in your case hg diff -c 123 ... would give you the diff for commit 123.
My guess is that hg outgoing is exactly what you want -- it compares what you've committed locally with what is at the default remote server and shows you a list of those changesets or with -p the commits.
That does, however, shows each changeset separately. If you want to see all the changes combined, you'd have to do hg diff -r HERE -r THERE or since -r HERE is a default, hg diff -r THERE
I see you've asked in a comment "How do I know what THERE is", where THERE is the last changeset remote has, and you can get that answer by doing hg outgoing. If hg outgoing shows it would send changesets 66, 67, and 68, then you want to do hg diff -r 65 to compare what's already there (65) with what's local (68).

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 :)