With Mercurial, how can I "compress" a series of changesets into one before pushing?

Question

Hi,

Let's say I have a local and a remote Mercurial repository. Now, I start working on a feature. I work on it, and when I think it's done, I commit the changeset. Testing it a bit more, I find that I could further improve this feature by tweaking something in the code. I make the change and commit. 20 minutes later, I find there's a bug in this new feature, so I fix it and commit that too.

I now have 3 changesets that I would really like to push to the remote repository as one changeset with message "Implementing feature X", for instance.

How can I do this without much hassle? I believe I could do it with patches, but it seems like a lot of work.

Answer 1

I've never used Mercurial, but this sounds a lot like what Martin Fowler was talking about on his blog not too long ago:

http://martinfowler.com/bliki/MercurialSquashCommit.html

Answer 2

How about the Collapse Extension?

Answer 3

Yes, you can do it with patches: Let's assume your work is in changesets 100 through 110, inclusive

1. Create a patch:

   % hg export -o mypatch 100:110

2. Update to 99:

   % hg update 99

3. Apply the patch with --no-commit (otherwise you'll get all your changesets back):

   % hg import --no-commit mypatch

4. Commit all changes at once:

   % hg commit

5. You now have two heads (110 and 111) which should be equivalent in terms of files they produce in your working directory -- maybe diff them for sanity before stripping the old ones out:

   % hg strip 100

OK, now that I have spelled it all out, it does seem lengthy, but having done it a bunch of times myself, I don't find it to be too much of a chore...

Answer 4

The histedit extension is exactly what you are looking for.

hg histedit -o

or

hg histedit --outgoing

will bring up a list of the outgoing changesets. From the list you can

• Fold 2 or more changesets creating one single changeset
• Drop changesets removing them from the history
• Reorder changesets however you like.

histedit will prompt you for the new commit message of the folded changesets which it defaults to the two messages with "\n***\n" separating them.

You can also get similar results using the mq extension, but it is a lot more difficult.

You can also use the collapse extension to just do folding, but it doesn't provide as nice a UI and doesn't provide a way to edit the resulting commit message. Editing the resulting commit message also allows for cleaning up the final message, which is something I always end up utilizing.

Answer 5

HistEdit will do what you want, but it's probably overkill. If the only thing you need is to fold some changesets together the Collapse Extension will do the job.