title: Mirror Folders in Repo
body: <p>We develop a web application. We have our core product developed in one Repo with several sub folders for different parts of the application. I would like the share a &quot;common&quot; function folder between these sub folders.</p>
  <p>Example:</p>
  <ul>
  <li>[trunk]/dbschema (Database schema. Required on DB servers and by developers)</li>
  <li>[trunk]/http (HTTP front end. Required on web servers and by most developers)</li>
  <li>[trunk]/api (API front end. Required on API servers and by some developers)</li>
  <li>[trunk]/deamon (Background script and optimization. Required on support server and by dev-ops)</li>
  </ul>
  <p>Now we would like to only check out the sub folder for each specific task/person. But we have &quot;common&quot; functions shared between different parts of the application.</p>
  <p>My hope is to create a <strong>/common</strong> in some of sub folder which is mirrored across the Repo.</p>
  <ul>
  <li>[trunk]/http</li>
  <li>[trunk]/http/common (Identical)</li>
  <li>[trunk]/api</li>
  <li>[trunk]/api/common (Identical)</li>
  <li>[trunk]/deamon</li>
  <li>[trunk]/deamon/common (Identical)</li>
  </ul>
  <p>We prefer not to check out the full Repo everywhere. Eg. The dbschema would not by necessary or wanted on a web server. Making it impossible to place the common in the [trunk]/.</p>
  <p>I've played with using svn:externals &quot;../http/common@HEAD common&quot; in the api folder. But this will makes common invalid when checking out a previous revision of the api folder. Instead of HEAD we could specify the relevant revision of common. Even predicting the next revision when committing and changing the externals. But this manual process is also not preferred and causes conflicts when merging tags and branches.</p>
  <p>I've been trying to read thru options in svn:externals. But haven't found anything suitable. If HEAD could be replace with a PARENT (made up) which refers to the revision of the properties folder. Then this would solve the challenges.</p>
  <p>But does anyone have any input on how I solve this. It would be greatly appreciated.</p>
  <p>Thank in advance - Jacob</p>