I used git-svn to create a git mirror of an SVN repository. The structure inside the SVN was a little off-standard, so git created a branch that has no common commit with the master branch.
A---B---C topic
D---E---F---G master
I know that commit A is based off commit E and I'm pretty positive that I've fixed the issues causing git not to recognize that fact (using filter-branch). What I want to do is re-attach topic to the master branch, setting E as the parent of A:
A---B---C topic
/
D---E---F---G master
git-rebase doesn't seem to work for me because the diff for commit A lists the creation of a whole lot of files that already exist in master, resulting in a huge number of conflicts.
From my understanding of git just setting E as the parent of A should be enough to solve all problems.
Is this possible? If it is, how can I do it?
Have a look at grafts (the graft file can be found in .git/info/grafts). The format is pretty simple:
<commit sha1> <parent1 sha1> <parent2 sha1> … <parentN sha1>
This makes git believe that a commit has different parents than it actually has.
In newer versions of Git, you want to use the replace mechanism to graft histories together:
git replace --graft …
Regardless of chosen approach (graft file or replace refs), use filter-branch to make grafts permanent (so the grafts file can be removed):
git filter-branch --tag-name-filter cat -- --all
Note that this rewrites history of the repository, so should not be used on shared repos!
If you only want to rewrite the history of the commits that are being grafted onto the master branch, for example, use this command:
git filter-branch --tag-name-filter cat -- master..