ConcatenatingChangesets

Concatenating multiple changesets into one

(See also: EditingHistory, HisteditExtension (which provides an editor-driven UI for this), CollapseExtension, RebaseProject (section Collapsing)).

Problem

Suppose you want to concatenate the last k changesets of a repository

into a single, combined changeset

Revert solution (using hg only)

Execute the following steps:

1: hg -R oldrepo update S

• This updates the working directory to revision S. Specifically, this means that the contents of the working directory are changed to that of revision S, and that S becomes the parent of the working directory.

2: hg -R oldrepo revert -r tip --all

• 

  This reverts the working directory to its contents at tip. Since the parent of the working directory is still S, this means that the combined contents of all changesets between S and S+k show up as the modifications in the working directory.

  Revert does not preserve copy and move history.

3: hg -R oldrepo commit -m "Combine changesets S+1..S+k"

• Committing these modifications creates a new changeset "S+k (combined)", containing combined changesets S+1 to S+k.

4: hg clone -r tip oldrepo newrepo

• 

  
  This assumes you want to get rid of your individual changesets (which are a dangling branch in oldrepo) and just keep the combined changeset. newrepo will now just have the combined changeset.

  This will strip out all other branches, not just the one dangling branch that you don't want. If you have other branches that you want to keep, specify their head revisions or branch names on the clone call:

  • hg clone -r tip -r branch1 -r branch2 -r branch3 oldrepo newrepo

  Or you can use the strip command provided by the Mercurial Queues Extension. Note that if you're planning to use mq, there's a much more convenient way to do the above...

Patch solution (using hg only)

Make a patch containing the changesets you want to concatenate.
1: hg -R oldrepo export --git -r S:tip > patchfile

Make a partial clone of the repository, up to and including the parent of S. This discards the patch changesets.
2: hg clone -r "p1(S)" oldrepo newrepo

Import the patch in the cloned repository as one changeset.
3: hg -R newrepo import -m "Combine changesets S+1..S+k" patchfile

Patch queue solution (using mq)

Integrate the changesets you want to concatenate in a patch queue (verify you don't have pending patches there using hg qseries).
1: hg qimport -r S+1:tip

(note how the start of the commit range specified is the fist commit we want to squash: S+1)

Pop all the patches but the first.
2: hg qgoto qbase

"Fold" unapplied patches, i.e. concatenate changesets.
3: hg qfold $(hg qunapp)
3: for /F %i in ('hg qunapp') do hg qfold %i (Windows)
This has the big advantage over the previous method that the commit messages will also be concatenated (separated by the * * * string). You can see the message using hg qhead and edit it using hg qrefresh -e.

Reintegrate the folded patch in the repository.
4: hg qfinish qbase
tip is now the concatenation of former changesets S:tip. There's no extra branch left, therefore no additional cleanup to do.

CategoryTipsAndTricks