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gitsvnmigrationgit-svnsvn2git

migrating svn to git: checksum mismatch on merged file

I'm trying to migrate a SNV Repo to Git manually and run into a problem:

I initialized my (odd) branch/trunk/tag structure with git svn init... and then tried to fetch the files while preserving history & logs. But git svn fetch fails when it reaches a revision including a merge between to svn branches, because of a checksum mismatch error.

I already tried different solutions presented on SO, but most of them have to do with an existing Git repo, which I don't have (yet) so e.g. git svn log won't work because the HEAD revision isn't fetched yet. Nothing worked...

My guess is, that the file was merged AND modified with one commit. Is there any way I can get around the checksum check? Or another solution?

Solution

  • Modifying files during a merge is a pretty normal use-case, as you need bring two different codebases together that might need some things done differently, so I don't think this is per-se the problem.

    But anyways, for a one-time migration git-svn is not the right tool for conversions of repositories or parts of repositories. It is a great tool if you want to use Git as frontend for an existing SVN server, but for one-time conversions you should not use git-svn, but svn2git which is much more suited for this use-case.

    There are plenty tools called svn2git, the probably best one is the KDE one from https://github.com/svn-all-fast-export/svn2git. I strongly recommend using that svn2git tool. It is the best I know available out there and it is very flexible in what you can do with its rules files.

    You will be easily able to configure svn2gits rule file to produce the result you want from your current SVN layout, including any complex histories that might exist and including producing several Git repos out of one SVN repo or combining different SVN repos into one Git repo cleanly.

    If you are not 100% about the history of your repository, svneverever from http://blog.hartwork.org/?p=763 is a great tool to investigate the history of an SVN repository when migrating it to Git.

    Even though git-svn is easier to start with, here are some further reasons why using the KDE svn2git instead of git-svn is superior, besides its flexibility:

    • the history is rebuilt much better and cleaner by svn2git (if the correct one is used), this is especially the case for more complex histories with branches and merges and so on
    • the tags are real tags and not branches in Git
    • with git-svn the tags contain an extra empty commit which also makes them not part of the branches, so a normal fetch will not get them until you give --tags to the command as by default only tags pointing to fetched branches are fetched also. With the proper svn2git tags are where they belong
    • if you changed layout in SVN you can easily configure this with svn2git, with git-svn you will loose history eventually
    • with svn2git you can also split one SVN repository into multiple Git repositories easily
    • or combine multiple SVN repositories in the same SVN root into one Git repository easily
    • the conversion is a gazillion times faster with the correct svn2git than with git-svn

    You see, there are many reasons why git-svn is worse and the KDE svn2git is superior. :-)