Combining multiple git repositories

Question

Let\'s say I\'ve got a setup that look something like

phd/code/
phd/figures/
phd/thesis/

For historical reasons, these all have their own g

Answer 1

You could try the subtree merge strategy. It will let you merge repo B into repo A. The advantage over git-filter-branch is it doesn't require you to rewrite your history of repo A (breaking SHA1 sums).

Answer 2

Perhaps, simply (similarly to the previous answer, but using simpler commands) making in each of the separate old repositories a commit that moves the content into a suitably named subdir, e.g.:

$ cd phd/code
$ mkdir code
# This won't work literally, because * would also match the new code/ subdir, but you understand what I mean:
$ git mv * code/
$ git commit -m "preparing the code directory for migration"

and then merging the three separate repos into one new, by doing smth like:

$ cd ../..
$ mkdir phd.all
$ cd phd.all
$ git init
$ git pull ../phd/code
...

Then you'll save your histories, but will go on with a single repo.

Answer 3

The sequence you suggested

git init
git add *
git commit -a -m "import everything"

will work, but you will lose your commit history.

Answer 4

To merge a secondProject within a mainProject:

A) In the secondProject

git fast-export --all --date-order > /tmp/secondProjectExport

B) In the mainProject:

git checkout -b secondProject
git fast-import --force < /tmp/secondProjectExport

In this branch do all heavy transformation you need to do and commit them.

C) Then back to the master and a classical merge between the two branches:

git checkout master
git merge secondProject

Answer 5

The git-filter-branch solution works well, but note that if your git repo comes from a SVN import it may fail with a message like:

Rewrite 422a38a0e9d2c61098b98e6c56213ac83b7bacc2 (1/42)mv: cannot stat `/home/.../wikis/nodows/.git-rewrite/t/../index.new': No such file or directory

In this case you need to exclude the initial revision from the filter-branch - i.e. change the HEAD at the end to [SHA of 2nd revision]..HEAD - see:

http://www.git.code-experiments.com/blog/2010/03/merging-git-repositories.html

Answer 6

git-stitch-repo from Aristotle Pagaltzis' answer only works for repositories with simple, linear history.

MiniQuark's answer works for all repositories, but it does not handle tags and branches.

I created a program that works the same way as MiniQuark describes, but it uses one merge commit (with N parents) and also recreates all tags and branches to point to these merge commits.

See the git-merge-repos repository for examples how to use it.