Generating patches in Mercurial - mercurial

I've looked for that in the manual, but I can't generate a patch for the last commit.
I tried
hg qnew patch_name
but it does only file with
# HG changeset patch
# Parent a6a8e225d16ff5970a8926ee8d24272a1c099f9c
I also tried
hg export tip
but it doesn't do anything. I committed the changes exactly.
How to generate a patch file with the last commit in?

The command to do this is export:
$ hg export -o FILE -r REV
It doesn't require redirection and will thus work correctly on any platform/shell.

Your hg export tip is the best way to do it, and the hg diff and hg log based answers are just lesser versions of the same. What exactly do you see/get when you type hg export tip? What does the output of hg log -p -r tip show?
The changeset tip is just means "the changeset that most recently arrived in my repository" which isn't as useful a concept as you might think, since hg pull and hg tag all create changesets too. If you really want the last thing you committed you'll need a more precise revspec.

Like so:
hg diff -r tip > tip.patch

You can use this command:
hg log -r tip -p > tip.patch
this will generate a patch for just that revision.

If you want to convert the latest commit to a patch file, use
hg qimport -r tip
This will replace the topmost regular commit with an applied MQ patch file.

To generate patches using "mq extensions" in mercurial, you can follow the below given steps. This will create a patch using mercurial:
1) Enabling mq extensions: Add the following lines to your hgrc file and save it.
[extensions]
mq =
2) Creating a patch using mq extensions: To create a patch using mq extensions you can do the following.
hg qnew -e -m "comment you want to enter" bug_name.patch
In the above command, -e flag is for editing the patch and -m flag is for adding a message to the patch.
3) Updating the patch: For updating the patch, you can use the following command when a patch is already applied.
hg qrefresh

Related

Mercurial: roll back an "hg commit --amend".

I accidentally did a "hg commit --amend" instead of just a commit. How can I roll back the commit to before the amend?
You can use hg reflog (from the journal extension) and hg reset <hash>.
hg reflog -v
should give something like:
<old-hash> -> <new-hash> <user> <timestamp> commit --amend <some-path>
if that is the amend you want to revert, just use:
hg reset <old-hash>
The commit will be reverted to what is previously was and the changes that were amended should now be uncommitted changes (check using hg status and hg diff).
If your version of Mercurial is new enough, I believe you should be able to use the hg unamend command from the uncommit extension that ships with Mercurial. This may require that obsolescence markers are enabled, I'm not sure.
Enable the uncommit extension, add this to your ~/.hgrc:
[extensions]
uncommit =
Actually run the unamend:
hg unamend
Find the latest saved backup in .hg/strip-backup directory
hg unbundle .hg/strip-backup/<latest backup>
Now you should have two heads - one with the amended commit, other one with two commits (first one - old commit before amending, second one caled: "temporary amend commit for (old commit hash)".
if you have histedit extension, you can do hg histedit on it in order to change it (e.g. select edit in order to achieve a state just before the commit, i.e. when you can see all changes using hg diff).
Don't forget to strip the old head.
It's 2022, and my attempts to use hg unamend have not worked. histedit is too clunky for my purposes, but the solution proposed by mariu52 elsewhere on this page can easily be adapted to work without histedit. It relies on the -k option of the strip subcommand.
In a nutshell:
Find the latest saved backup in the .hg/strip-backup/ directory
Run hg unbundle .hg/strip-backup/<latest backup> where <latest backup> signifies the full filename.
Run hg heads and note the rev number corresponding to the amendment.
Let's call this $AMENDREV; this is the rev number we will strip in the next step.
Run hg strip -k --rev $AMENDREV
Using the -k option in the strip command is critical.
WARNING: this procedure will in effect erase the memory of any add or remove commands
that were pending when the amend command was executed.
For example, in the transcript below, the hg add file2 command is effectively
forgotten after the strip command is executed.
For clarity, here's a transcript based on the above recipe.
$ mkdir tmp ; cd tmp
$ ls
$ echo 1 > file1
$ echo 2 > file2
$ hg init
$ ls
file1 file2
$ hg add file1
$ hg commit -m 'one file'
$ hg add file2
$ hg amend -m 'amendment'
saved backup bundle to /tmp/tmp/.hg/strip-backup/d332ee829c21-5a5f23b0-amend.hg
$ hg unbundle -u .hg/strip-backup/d332ee829c21-5a5f23b0-amend.hg
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 1 files (+1 heads)
new changesets d332ee829c21 (1 drafts)
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
updated to "1a445f3252eb: amendment"
1 other heads for branch "default"
$ hg heads
1[tip]:-1 d332ee829c21 2022-11-09 01:55 -0500 peak
one file
0 1a445f3252eb 2022-11-09 01:55 -0500 peak
amendment
$ ls
file1 file2
$ hg strip -k -r 0
saved backup bundle to /tmp/tmp/.hg/strip-backup/1a445f3252eb-bfaab5ec-backup.hg
$ ls
file1 file2
$ hg list
r0: peak tip 2022-11-09 01:55 -0500
one file
file1
$
hg unamend part of Mercurial 4.5 (2018-02-01).
NOTE: This answer is now deprecated. See the answer from #Sorina Sandu instead.
See hg help commit, where it says:
The --amend flag can be used to amend the parent of the working
directory with a new commit that contains the changes in the parent in
addition to those currently reported by "hg status", if there are any.
The old commit is stored in a backup bundle in ".hg/strip-backup" (see
"hg help bundle" and "hg help unbundle" on how to restore it).

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>

hg shelve equivalent of git stash drop

I have the hg shelve (not attic) extension installed, and I want to drop a patch. In git it would be git stash drop. How do I do this using the shelve extension?
From the Mercurial shelve documentation (or using hg help shelve):
To delete specific shelved changes, use "--delete". To delete all shelved changes, use "--cleanup".
options:
-d --delete delete the named shelved change(s)
So if your patch was called my-patch, then you would delete it using:
hg shelve -d my-patch
If you don't want to use shelves, you can do it the following way.
hg diff > mylocalchanges.txt
hg revert -a
# Do your merge here, once you are done, import back your local mods
hg import --no-commit mylocalchanges.txt
The Mercurial shelve extension stores patches under .hg/shelved. Each is a simple patch file, and the filename is the name of the patch. So to remove a patch called 'mypatch' I can simply remove the file 'mypatch' from .hg/shelved:
rm .hg/shelved/mypatch
I created two shell scripts based on minaz's answer:
hgshelve
#!/bin/sh
hg diff > $1 && hg revert -a
hgunshelve
#!/bin/sh
hg import --no-commit $1 && trash $1
Put them in ~/bin. You need sudo apt-get install trash-cli for the trash command (or modify the script to either not remove the patch file, or use rm if you prefer).

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.

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 :)