title: CruiseControl.NET build nightly IfModificationExists since Last Build Label
body: <p>I am using one server to build the same project both continuously and nightly; however I would like the nightly build to only build if a modification exists during the day.  I am hoping to achieve this with the constraint that both builds use the <strong>same working folder</strong>.</p>
  <p>The two options I am considering are:</p>
  <ol>
  <li><p>Polling the continuous build and only build the nightly build if a continuous build has occurred - possibly using some token system (continuous build sets token, nightly clears token).</p>
  </li>
  <li><p>Running a prebuild task to revert the source code to the Last Build Time</p>
  </li>
  </ol>
  <p>I am leaning towards the second option as it decouples the build scripts, but it seems to be a much harder task.</p>
  <p>Suggestions and tips to doing this would be appreciated!</p>
  <p><strong>Added Information:</strong></p>
  <blockquote>
  <p>The CI build is a quick build of the
  solution in one configuration and
  maybe runs some fast unit tests.</p>
  <p>The nightly build cleans the build
  environment, builds the software, packages into an
  installer, runs extended tests, labels
  the source code repository, deploys
  the installer to a server share for
  manual testers to pick up, and emails
  the test team that a testable build
  has been made.</p>
  <p>I only want the
  nightly build to occur if there were
  any check-ins during the day so that testers don't get plagued with repeat emails for essentially the same build.</p>
  </blockquote>