title: How to get a stack trace for "Invalid chrome URI" exceptions?
body: <p>I'm debugging a XUL-based Firefox extension which has been broken by Firefox 46 release.</p>
  
  <p>When I run the extension, the <a href="https://developer.mozilla.org/en/docs/Tools/Browser_Console" rel="nofollow">Browser console</a> shows:</p>
  
  <pre><code>Invalid chrome URI: /
  </code></pre>
  
  <p>with neither line numbers nor stack trace.</p>
  
  <p>On Web forums, <a href="https://groups.google.com/forum/#!topic/mozilla.dev.extensions/AVMN2-mtNhI" rel="nofollow">I've read</a> that ChromeBug could be used for that. Then, I've tried the latest stable version of ChromeBug (1.7.2) but it hasn't been updated since oct. 2014, and seems to be incompatible with recent Firefox versions.</p>
  
  <p>Because the extension is an "old-style" one, I cannot use the <a href="https://developer.mozilla.org/en-US/Add-ons/Add-on_Debugger" rel="nofollow">Add-on debugger</a>, therefore I used the <a href="https://developer.mozilla.org/en-US/docs/Tools/Browser_Toolbox" rel="nofollow">Browser toolbox</a>, but it doesn't display the exception.</p>
  
  <p>Considering the number of lines of the extension, wandering around in the code is not an option. Any idea how I could get a stack trace?</p>