title: git-svn-id is missing from some commits
body: <p>I have an old SVN repository that I checked out using <code>git-svn</code> in order to work on it and push to Heroku. I was doing a pretty standard <code>git push heroku master</code>, <code>git svn rebase</code>, <code>git svn dcommit</code> dance and things were fine.</p>
  
  <p>However, recently I've been doing a fair bit of git work and hadn't done a <code>git svn rebase</code> in a while. Now when I try to do a rebase it fails because of merge conflicts, despite me being the only person committing to the repo and only working on master.</p>
  
  <p>Figuring that it might be the working copy that's the problem I did a new <code>git svn clone</code> and then a <code>git remote add heroku</code> and <code>git pull heroku master</code>. The pull does a fast-forward merge with no problems, but <code>git svn rebase</code> still fails.</p>
  
  <p>I did a simple <code>git log</code> and I see that I have some old commits missing <code>git-svn-id</code>s:</p>
  
  <pre><code>commit def8bab861314c67d4e8227e03775d19045d21d1
  Author: peterr
  Date:   Fri Sep 21 16:17:33 2012 +0000
  
      PHP Cedar support.
  
      git-svn-id: http://vcp.unfuddle.com/svn/vcp_bbsit@24 b6b24ac3-8b7a-4c11-a811-49c5d0334e85
  
  commit f51bd78fb07dde6ec1dc4e0ba51a48f2b6bd1bd6
  Author: pr1001
  Date:   Mon Aug 20 19:39:42 2012 +0200
  
      Specify port correctly
  
  commit 153bb2929080898dcab46142120def0f4964dfab
  
  ...
  
  commit 5a416fa3af9f64aa353d5171bedfaa563115ff62
  Author: pr1001
  Date:   Mon Aug 20 17:22:58 2012 +0200
  
      PHP Cedar support.
  
  commit e0b35588d03082a3a4ab49a7b590f206346046c0
  Author: j
  Date:   Fri Aug 3 08:13:33 2012 +0000
  
      change email
  
      git-svn-id: http://vcp.unfuddle.com/svn/vcp_bbsit@23 b6b24ac3-8b7a-4c11-a811-49c5d0334e85
  </code></pre>
  
  <p>From <a href="https://stackoverflow.com/a/9889025/46768">an SO answer</a> I gather that I might be able to rewrite the commit messages to add the missing information, but I wonder whether that wouldn't be even worse.</p>
  
  <p>Looking at the messages, it looks like I have some duplicate commits, such as the 'PHP Cedar support' one. I'm really perplexed why I have these duplicates, though I suspect that they may be relayed to the failed <code>git push heroku master</code> I had the other day in which I was told the repositories were out of sync. <code>git pull heroku master</code> seemed to bring in absolutely no changes and fixed the issue, but perhaps it brought in the duplicate commits.</p>
  
  <p>So, given all this my question is simply, how might I proceed? I have a working app on Heroku and an older working code base in the SVN repo, but I don't see any easy way how to cleanly get the newer commits into SVN. Should I cherry-pick them? Would I then need to nuke the Heroku app in order to not have the duplicates come back?</p>