# Grafting Alternate History 3 messages from 2012-08-31 to 2012-09-04. Participants: dag@cray.com, Andreas Schwab. Thread: https://gitlist.dev/t/31401 ## dag@cray.com, 2012-08-31 23:39 Subject: Grafting Alternate History Message-ID: URL: https://gitlist.dev/e/nng7gse7hrl.fsf%40transit.us.cray.com ``` I have an unfortunate situation where I have two subversion repositories for the same project, one a public version and one a private version. Because they are mirrors of svn repositories, they have very different histories as far as git is concerned. This is not all that uncommon but of course I would like to manage things in git. git-svn is great for interacting with one svn repository. The public svn repository has a fully-supported git mirror. The private repository also has a fully-supported git mirror. But I need to check in changes to the private repository via git-svn. I eventually need to check in changes to the public repository as well but that is orders of magnitude less frequent. A manual diff+patch+git-svn is acceptable for now. I am wondering if it's possible to graft the history of one of the git mirrors onto an empty branch of the other and share changes between them. I need to take updates from the public repository and apply them to the private repository. This is a frequent operation. I have been essentially using manual diff+patch but that is highly error-prone and annoying. For example, let's say we take a local copy of the private repository. I would like to somehow create an empty branch in that local copy and then populate it with the history of the public repository. I would like to be able to specify a git diff-like command on the public graft branch to get some changes over a range of commits and apply those changes to one of the private branches (say master). If I could use a git-merge-like or git-rebase-like command, so much the better. I would like to do the same in reverse but as I said that is a much less common operation. Has anyone done anything like this before? Is it even theoretically possible to manage disjoint histories like this? Thanks for your help! -Dave ``` ## Andreas Schwab, 2012-09-01 06:48 Subject: Re: Grafting Alternate History Message-ID: URL: https://gitlist.dev/e/m2harick7z.fsf%40igel.home In-Reply-To: ``` writes: > For example, let's say we take a local copy of the private repository. > I would like to somehow create an empty branch in that local copy and > then populate it with the history of the public repository. I would > like to be able to specify a git diff-like command on the public graft > branch to get some changes over a range of commits and apply those > changes to one of the private branches (say master). You can set up (the git mirror of) the public repository as a remote in the private repository and git cherry-pick the commits you want to copy over. Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different." ``` ## dag@cray.com, 2012-09-04 22:56 Subject: Re: Grafting Alternate History Message-ID: URL: https://gitlist.dev/e/nngmx155rdr.fsf%40transit.us.cray.com In-Reply-To: ``` Andreas Schwab writes: > You can set up (the git mirror of) the public repository as a remote in > the private repository and git cherry-pick the commits you want to copy > over. Now why didn't I think of that!? :) Thanks for helping an old bumbler along. :) -Dave ```