Traceback when no milestones are defined

[anonymous]

When no milestones are defined in a project, selecting the burndown tab results in a traceback. This should be fixed to display something useful, or at least not crash trac.

Code fragment:

 168. data['draw_graph'] = req.hdf['draw_graph'] = True
 169. self.update_burndown_data()
 170.
 171. data['burndown_data'] = req.hdf['burndown_data'] = []
 172. data['burndown_data'] = req.hdf['burndown_data'] = self.get_burndown_data(db, selected_milestone, components, selected_component)
 173.
 174. add_stylesheet(req, 'hw/css/burndown.css')
 175.
 176. self.update_burndown_data()
 177.

[anonymous]

Adds some basic validation, so trac shouldn't crash

[Ryan J Ollos]

(In [11225]) Fixes #4587: Raise a TracError if no milestones are defined.

[Ryan J Ollos]

(In [11226]) Refs #4587: Egg was accidentally added in [11225].