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Converting SVN to GIT

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This is a repost of http://dogma.co.uk/blog/10-converting-svn-to-git

We've recently set about converting all our old SVN repositories to GIT. The process is quite easy thanks to the git svn command, but there are some gotchas. So, I'll detail the process below.

Every revision in a SVN repository has an author, these authors need to be migrated to the new GIT repository; which is done by compiling a text file listing the existing SVN username along with the author's new GIT equivalent. The format of the text file is as follows:

svn_username = GIT User Name <user@dogma.co.uk>

You can list as many users in this file as you like, duplicating the GIT details if required. To generate a list of the SVN author's run the following with the SVN repo:

svn log --xml | grep author | sort -u | perl -pe 's/.>(.?)<./$1 = /'

A potential gotcha here is that git svn will fail if the SVN username has spaces in it. This caught me out as our older SVN repos were originally hosted on a Visual SVN Server, which used the username Visual SVN. If you have a username with spaces in it, you must change that username in each revision the author is attached to.

To identify the offending revisions, run:

svn log | sed -n '/svn_username/,/-----$/ p'

Then to fix the username, run the following on each revision:

svn propedit svn:author -r revision --revprop svn_url Once you have created an authors file (usually called authors.txt), run the following in an empty directory to clone the SVN repo into a new temporary GIT repo called git-tmp:

git svn clone --stdlayout --no-metadata -A authors.txt svn_url git-tmp

Change directory into git-tmp and run the following to fetch the SVN repo structure:

git svn fetch

Now you'll want to link the temporary repository to your destination remote GIT repo, by running the following:

git remote add remote git_url
git push -u remote master

The commands above will only push the master (what was trunk) to the remote repo. Currently, any branches you have in the SVN repo only exist as remote references in git-tmp. To make these references local branches and then push them to the server, run the following for each branch you would like to keep:

branch=branch; remote=remote; git checkout -b $branch remotes/$branch; git push -u $remote $branch; git checkout master

Providing all went well, you can now discard the temporary GIT repo and clone a fresh copy of your new remote GIT repo.

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