title: git-svn migration fatal: not a valid SHA1 update-ref refs/heads/master refs/remotes/trunk: command returned error: 128
body: <p>Trying to migrate a large but linear svn repository to git. The svn repository does not have the standard layout (trunk, branches, tags)...just one directory with the trunk.</p>
  
  <p>Ubuntu 12.4 LTS,git 1.7.9.5.</p>
  
  <pre><code>$ git svn clone https://coawstmodel.sourcerepo.com/coawstmodel/COAWST --authors-file=../users.txt COAWST
  
  ...
  
      D   WPS/metgrid/storage_module.F
      D   WPS/metgrid/process_domain_module.F
  W: -empty_dir: WPS/metgrid/gridinfo_module.F
  W: -empty_dir: WPS/metgrid/input_module.F
  W: -empty_dir: WPS/metgrid/interp_option_module.F
  W: -empty_dir: WPS/metgrid/module_date_pack.F
  W: -empty_dir: WPS/metgrid/process_domain_module.F
  W: -empty_dir: WPS/metgrid/storage_module.F
  r635 = c19181c9718e701788b540ed0cc559e4fbddf413 (refs/remotes/git-svn)
      M   Tools/Docs/COAWST_User_Manual.doc
  r636 = 1b7849c3e5a20856c9ddb909a5f53ddf8501ad33 (refs/remotes/git-svn)
  Auto packing the repository for optimum performance. You may also
  run "git gc" manually. See "git help gc" for more information.
  Counting objects: 14143, done.
  Delta compression using up to 8 threads.
  Compressing objects: 100% (14039/14039), done.
  Writing objects: 100% (14143/14143), done.
  Total 14143 (delta 8350), reused 0 (delta 0)
  fatal: refs/remotes/trunk: not a valid SHA1
  update-ref refs/heads/master refs/remotes/trunk: command returned error: 128
  </code></pre>
  
  <p>I have tried variants with combinations of -s, -t Trunk, -t COAWST, --preserve-empty-dirs (which I would like to do), --no-meta-data (per Pro Git)...always the same final error.</p>
  
  <p>Thanks for any suggestions!</p>