Mercurial: beheading a head

Question

There is a commit that just didn't work, so I want to abandon it without deleting it from history.

I have updated from an earlier revision and committed, thus creating a new head.

I don't have branches, I don't want branches, I just want to simply go on with the new head exactly as it is, nothing fancy, no merge, no worries, just go on forgetting the previous one.

I can't seem to find how to do that, and I'm starting to believe it can't be done. All I find is stuff about branches, or stuff about merging.

Answer 1

You want to use the Backout command, this removes the changes made by the change set from any child changeset

Check this out for a good explination Mercurial Backout

Answer 2

Update your repository to the head with the revision that you want to forget about, then use the --close-branch option to hg commit to mark that branch as closed. Then update to the head of the branch that you do want, and continue working.

You can still see the closed branch if you use the -c option to hg heads, but it won't show up by default and hg merge will know not try to merge with the closed head.

You will need to use hg push --force the first time you push this closed head to another repository since you are actually create additional heads in the remote repository when you push. So tell Mercurial that this is okay with --force. People who pull the closed head wont be bothered by any warnings.

Answer 3

Since it is a head it will always show up during push etc. There's no built-in way to ignore a certain head. Commands like push take a rev specifier that you can use to make it only push changes predecessing a revision (instead of the full graph).

But in the longer term, I find this is not a workable solution. The best thing I can recommend is to hg export the changeset into a bundle and then hg strip it (you could also locate the strip-backup, just see the commands output for where that got stuffed). Keep the bundle around as a backup.

Another solution would be to push the changeset into a "historical" clone of your repository that contains all your dead-end developments like this. Have a separate, clean repo for your trunk.

Answer 4

I know you don't want to work with branches at this stage, which is fine, but that's exactly what you've done. When you went back to an earlier version and committed something that worked you created a branch - an unnamed branch, but a branch all the same.

There's no problem with just carrying on just as you are and not worrying about having multiple heads, but if you want to tidy things up so you don't accidentally pick the wrong head one time then you can kill off the old branch.

There's a good section in the Mercurial documentation that takes you through a number of options around Pruning Dead Branches.

I think the best option for you is to mark the old branch as "closed". If you old head is revision "123" then:

hg update -r 123
hg commit --close-branch -m 'Closing old branch'
hg update -C default