How can I modify the file path in a set of Git patches?

Question

I'm working on a Git repo that's been pulled from an SVN repo using git svn. Many moons ago, the SVN repo was created from a source tarball of the original (upstream) project. The original project had a file structure like the following:

/
  COPYING
  README
  src/
      ...many source files...

However, when the SVN repo was created, the README files, etc., were stripped out, and the app was created with src/ as the root, so the repo now just looks like:

/
  ...many source files

I recently converted this SVN repo into a Git repo. The original project is also in a Git repo, and I'd like to start tracking upstream changes so I can easily see what custom changes have been made (and submit patches back to the original project, if applicable). I've found the commit in the upstream repo that our SVN repo was created from, so now I'd like to apply our changes to that commit (in a branch). I can easily create a set of patches using git format-patch and apply them to the cloned upstream repo...except that the file structures are different, so the patches don't point to the correct files anymore. Is there a way to apply the patches from git format-patch to the src/ directory in the cloned repo? (Note that the Git patches also have the necessary info like the original author name, email, and date, which I'd also like to apply and not have to do by hand, i.e., by messing around with GIT_AUTHOR_EMAIL, etc.)

Answer 1

Seems to me that you should be able to use git filter-branch to change the paths in the previously-cloned-from-SVN repo. Then, after all the file paths have been updated, you can now just use git format-patch to create patches that will apply to the newly-cloned-from-upstream repo.

Try:

git filter-branch --tree-filter 'mkdir src; git ls-tree --name-only $GIT_COMMIT | xargs -I files mv files src'

Answer 2

I recently had a similar problem. My solution was to create a new target repository with a src subdirectory, then I created a set of patches in the source repository:

/data/source-repository$ git format-patch -k --root

then those patches were applied to the src directory in the target repository:

/data/target-repository$ git am -k --committer-date-is-author-date --directory src ../source-repository/*.patch

All patches from the source repository ended in src in the target repository, i.e. all paths were tweaked accordingly.

From there you could again create patches and import those into the upstream repository inside of a branch.