title: Why do I get a svn: Illegal repository URL '' error when using maven's release plugin?
body: <p>I was using </p>
  
  <pre><code>mvn release:branch ...
  </code></pre>
  
  <p>And I got this cryptic error:</p>
  
  <pre><code>[INFO] BUILD FAILURE
  [INFO] ------------------------------------------------------------------------
  [INFO] Total time: 27.391s
  [INFO] Finished at: Mon Jan 07 17:22:46 PST 2013
  [INFO] Final Memory: 7M/245M
  [INFO] ------------------------------------------------------------------------
  [ERROR] Failed to execute goal org.apache.maven.plugins:maven-release-plugin:2.3.2:branch (default-cli) on project XXX: Unable to commit files
  [ERROR] Provider message:
  [ERROR] The svn command failed.
  [ERROR] Command output:
  [ERROR] svn: Commit failed (details follow):
  [ERROR] svn: Illegal repository URL ''
  [ERROR] -&gt; [Help 1]
  [ERROR]
  [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
  [ERROR] Re-run Maven using the -X switch to enable full debug logging.
  [ERROR]
  [ERROR] For more information about the errors and possible solutions, please read the following articles:
  [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException
  </code></pre>
  
  <p>What is causing this?</p>