title: Apply mercurial bundle file on different changeset
body: <p><strong>TLDR</strong>: I have an HG bundle  with parent X, but revision X does not exist in my repo. However, I am <strong>sure</strong> that the files of revision Y are identical to revision X. How do I apply the bundle?</p>
  
  <p><strong>Background:</strong></p>
  
  <p>I use <code>hgsubversion</code> to interact with an SVN repo.</p>
  
  <p>There were some changes I did not want to commit. <code>hgsubversion</code> does not support partial pushes.</p>
  
  <p>I used to workaround by manually creating temporary exports/patch files, or manually restoring .orig files (result of <code>hg revert</code>).</p>
  
  <p>In this case I committed the changes I did not want to push, then used <code>hg strip</code>, then pushed, then tried to use <code>hg unbundle .hg/strip-backup/file</code>.</p>
  
  <p><strong>Problem</strong>: <code>hgsubversion</code> replaces the original changeset with a new one it imports from SVN after it's committed it. Result: the changeset ID changes. This is a problem because now <code>hg unbundle</code> no longer works, as it relies on the parent changeset being there (but it's been stripped).</p>
  
  <p>Ironically, <code>hgsubversion</code> itself uses <code>strip</code> and thus has a backup file I can use to strip the new rev, add the stripped old revision, then apply the bundle with my revisions, export the patch, strip both, and restore the SVN revision. But this sounds... extremely painful and stupid. Is there nothing better I can do?</p>
  
  <p>(<code>hg transplant</code> doesn't seem to like the bundle without having the parent in the repo, either)</p>