Can I get back my code changes after hg update removed them? - mercurial

I am new to Mercurial. I had made some some changes in the code in some of the files and i hadn't committed them yet. but when I did hg update -c <branch-name>, all my code changes were gone. Is there any way I can get my code changes back or am I screwed?

Are you perhaps using a very, very, old version of Mercurial?
The help for hg update shows that -c won't discard uncommitted changes:
-C --clean discard uncommitted changes (no backup)
-c --check update across branches if no uncommitted changes
That's been the case for at least four years. If you try to update to a revision that would discard your local changes Mercurial warns you:
ry4an#four:~/test$ hg checkout 0
abort: uncommitted changes
(commit or update --clean to discard changes)
If you used -c it should have done nothing. If you used -C you should find whomever suggested you do so and yell at them.
Sorry for your loss. :(

Unfortunately no, as explained in the update help (hg help update), --clean don't create backup.
Check if you can get the old version of your files with your text editor with CTRL + Z, it already saved my life.

Related

how to undo hg update -C -r 3 command in mercurial

I'm a new user of tortoisehg and accidently I typed the command 'hg update -C -r 3' and a lot of files removed. Can I undo this command? I'm really desperate, thanks for any help and so sorry for poor English.
When you updated to an older revision, your TortoiseHg will probably look like this:
So you simply need to go to your tip (most recent revision) and click update. All your "lost" files will be "restored" again. The "" are there because nothing is really lost just because you update to a different revision. Every revision is stored in the repository.
But wary that uncommitted changes will be lost when you update to a different revision, but you have to confirm that explicitly!

Mercurial workflow: why do I seem to commit everything twice?

I'm trying to grasp the Mercurial basics so please bear with me. :) My current workflow is as follows:
do some work until I'm ready to commit or need the others' changes
pull
at this point I'd like to merge my work with the latest changesets and commit, however Mercurial insists on me committing before merging
so it goes like "commit, merge, commit" and I'm basically committing everything twice, writing the same notes in both changesets and pushing two changesets at a time
Is it intended to be so? Is it possible to have just one changeset coming from me with every merge? Is it indeed desirable?
I've read a lot of online manuals but still feel I do not have solid understanding of the process. All comments are welcome. Thanks!
EDIT: Turns out I didn't know that update could merge incoming changes with uncommitted edits.
Merging always creates a separate changeset in Mercurial.
Plus, merging is not possible as long as you have uncommitted stuff in your local repository.
So the solution is to commit first, and pull and merge afterwards.
This will always result in two changesets, not one.
(...because merging always creates a separate changeset)
But you don't commit the same stuff twice, and especially you shouldn't write the same commit message twice:
The first commit is what you actually changed ("fixed a bug in the foo bar").
The second commit is just the merge (TortoiseHG actually pre-populates the commit message with "Merge", 99% of the time I just leave it like that).
This workflow will prevent a merge in the history, but you still do a merge as noted below:
Do some work until you are ready to commit or need another's changes.
hg pull
hg update (Note: hg pull -u does this and the previous in one step.
During hg update, your uncommitted changes will be merged with the new tip of your current branch. You will still have to resolve any conflicts.
hg commit when ready.
I still recommend if you have extensive changes to commit first before pulling/merging because it is easier to start over by updating to that changeset if the merge goes badly.
Keeping the hg pull and hg update separate allows you to look at the incoming changesets and predict how the merge will go.
The reason is feels strange is that you delay your commit until you want to integrate with the others.
A big feature of distributed version control is that commits are local. Because they're local you should commit often — commit every time you have a small consistent chunk of work done. Your commits are not inflicted on others immediately so you wont interrupt them by making many small commits.
If you begin making more commits you'll see that your workflow becomes:
$ hg commit -m "Refactoring for Issue123"
$ hg commit -m "Basic functionality for Issue123"
$ hg commit -m "Fixed off-by-one error (Issue123)"
$ hg commit -m "Finished implementing Issue123"
$ hg commit -m "Added more tests for Issue123"
$ hg commit -m "Begin use new function from Issue123"
$ hg pull
$ hg merge
$ hg commit -m "Merge"
Here the ratio of merge commits to "real" commits is much more sensible.
Many people (myself included) like to use the rebase extension to avoid the merge completely. That extension linearizes the commits by faking the history so that it looks like you did your four commits after the changesets you pulled down with hg pull. The only change in workflow is that you hg rebase instead of hg merge above and then skip the final commit.

Mercurial - basic process to revert a merge and try again

We merge using this process:
cd c:\myapp
hg pull ssh://hg/myapp-1_0_1
hg merge
Now sometimes we mess up the merge or sometimes we get an error (ie: "can't merge file xxx - file in use"). Usually I just delete my c:\myapp repo, re-clone from the remote master repo and start over. This works but it's a pain. What is a better way?
I've read about using hg update -C but I'm not clear on the process. So you'd do hg update -C, this would delete the merged files but keep the changesets that were pulled down, and then you'd issue the hg merge command again and try again?
Update Regarding the related question: hg update -C still keeps the changesets in the repo which were pulled down with hg pull - how can you get rid of those?
hg update -C is just perfect. Why would you want to get rid of the pulled changesets? Because the update command updates to the head of the pulled changes? If this is your problem with the pulled changes, run hg update -C <revision-of-your-local-head> and don't care about the pulled changes, probably you'll pull them again at some point anyway. After the update proceed your work or try the merge again.
However, if your really want to get rid of pulled changes, use the strip command.
See this post How to abandon a hg merge?

Discard all and get clean copy of latest revision?

I'm moving a build process to use mercurial and want to get the working directory back to the state of the tip revision. Earlier runs of the build process will have modified some files and added some files that I don't want to commit, so I have local changes and files that aren't added to the repository.
What's the easiest way to discard all that and get a clean working directory that has the latest revision?
Currently I'm doing this:
hg revert --all
<build command here to delete the contents of the working directory, except the .hg folder.>
hg pull
hg update -r MY_BRANCH
but it seems like there should be a simpler way.
I want to do the equivalent of deleting the repo, doing a fresh clone, and an update. But the repo is too big for that to be fast enough.
Those steps should be able to be shortened down to:
hg pull
hg update -r MY_BRANCH -C
The -C flag tells the update command to discard all local changes before updating.
However, this might still leave untracked files in your repository. It sounds like you want to get rid of those as well, so I would use the purge extension for that:
hg pull
hg update -r MY_BRANCH -C
hg purge
In any case, there is no single one command you can ask Mercurial to perform that will do everything you want here, except if you change the process to that "full clone" method that you say you can't do.
hg up -C
This will remove all the changes and update to the latest head in the current branch.
And you can turn on purge extension to be able to remove all unversioned files too.
To delete untracked on *nix without the purge extension you can use
hg pull
hg update -r MY_BRANCH -C
hg status -un|xargs rm
Which is using
update -r --rev REV revision
update -C --clean discard uncommitted changes (no backup)
status -u --unknown show only unknown (not tracked) files
status -n --no-status hide status prefix
hg status will show you all the new files, and then you can just rm them.
Normally I want to get rid of ignored and unversioned files, so:
hg status -iu # to show
hg status -iun0 | xargs -r0 rm # to destroy
And then follow that with:
hg update -C -r xxxxx
which puts all the versioned files in the right state for revision xxxx
To follow the Stack Overflow tradition of telling you that you don't want to do this, I often find that this "Nuclear Option" has destroyed stuff I care about.
The right way to do it is to have a 'make clean' option in your build process, and maybe a 'make reallyclean' and 'make distclean' too.
If you're looking for a method that's easy, then you might want to try this.
I for myself can hardly remember commandlines for all of my tools, so I tend to do it using the UI:
1. First, select "commit"
2. Then, display ignored files. If you have uncommitted changes, hide them.
3. Now, select all of them and click "Delete Unversioned".
Done. It's a procedure that is far easier to remember than commandline stuff.

How can I recover a removed file in Mercurial (if at all)?

Accidentally, by using a GUI as opposed to CLI, I removed every file in a Mercurial project.
I recovered with Revert ok and lost some work, which as I have time machine I could easily get back. But is there a way of un-remove/undelete such files? Trawled through the manual and googled but cannot see anything. Any plugins?
I am probably answering my own question here but the files were gone from the directory and were not in the trash to recover so I am assuming Remove is irrevocable?
p.s. I know that hg forget or hg remove -Af will remove without deleting from the directory but my question has to do with the error I made as opposed to cool thinking the action through.
First, use hg grep to find the deleted file you wish to recover. The output of this command will show you the last revision for which the file was present, and the path to the deleted file.
Second, run hg revert -r <revision number> <path to deleted file>
The deleted file will now be in your working copy, ready to be committed back into head.
Quote from comment:
I set up a repository, committed all, Removed and then committed again
If this is the case then you just need to update the working directory to the previous revision:
$ hg update -C -r-2
Note the negative revision number. If the files you deleted aren't in the previous revision, you can find them by using:
$ hg log -v
For Mercurial 1.6 and above
If you know the name of the delete file you can find its revision easily with:
hg log -r "removes('NAME.c')"
This will give you the revision in witch a file called NAME.c (in the root) is deleted.
Then you can revert the file to the previous revision with (like other answers):
hg revert -r <revision number> <path to deleted file>
You can use a file name pattern instead to adapt to what you know, for example you can use **/NAME.c to search in all directories. You can read about it in File Name Patters. And use this link to know about the new revset specifications.
Well this worked for me.
hg revert -r revision pathToTheFile
An addition to the accepted answer - this is faster if you want to undo all removals in a commit. I deleted a large folder with a few hundred files in it and did hg addremove, which was not at all my intent, so had to undo all of those deletes.
Using Find deleted files in Mercurial repository history, quickly? + xargs + tr, revert all revision -3 removals to the version from revision -4:
hg log -r -3 --template "{rev}: {file_dels}\n" | tr ' ' '\n' | xargs hg revert -r -4
Note that this will fail if any of your files have spaces in the name; http://hgbook.red-bean.com/read/customizing-the-output-of-mercurial.html doesn't appear to have any templates where {file_dels} is split by \n at the moment.
You can undo the last commit on a repo with hg rollback. There's only one level of rollback available, so if you did the remove with more than one commit, this won't completely undo your change. This only works on your local repository, so if you've pushed you won't be able to undo it in the remote repo.
You can remove committed revisions using the hg strip command, which is provided by the mq (Mercurial Queues) extension. This should give you back your files.
Make a backup before trying that out, because it will alter Mercurial's database of changesets.
The following worked for me.
hg revert -r <Revision Number> <File Name>
(Optional, to revert all files)
hg revert -r <Revision Number> --all
The below method is straightforward and so stupid that it cannot go wrong.
If you have deleted or renamed multiple files, it will be ok.
hg clone mydirectory mydirectory1
and now you start mc (or Far Manager) and compare what it was vs what it has become.
when it's done, just delete mydirectory1.