Importing one Mercurial repository into another

In the ion trap group, we usually use Mercurial for version controlling software we write for experimental control, data analysis, and so on. This post outlines how to import the full history of one repository into another. This can be useful for cases where it makes sense to move a sub-project directly into its parent, for example.

Convert the soon-to-be child repository

With the Mercurial convert extension, you can rename branches, move, and filter files. As an example, say we have a repo with only the default branch which is to be imported into a super-repository.

For starters, we will want all our files in the child repo to be in a subdirectory of the parent repo and not include the child's .hgignore. To do this, create a file filemap.txt with the following contents:

rename . child
exclude .hgignore

The first line will move all files in the repo's top level into a directory named child.

Next, optionally create a branchmap.txt file for renaming the default branch to something else:

default child-repo

Now convert:

hg convert --filemap branchmap.txt --branchmap branchmap.txt child/ converted/

Pull in the converted repository

From the parent repo:

hg pull -f ../converted

Ensure the child commits are in the draft phase with:

hg phase -f --draft -r <first>:<last>

Rebase as appropriate

hg rebase -s <child rev> -d <parent rev>

To keep the child's changed branch name, use the --keepbranches option.