servo: Merge #6506 - notify_darwin should trap import errors (from mt2d2:darwin_notification_imports); r=metajack

notify_darwin should trap import errors and should provide the useful package name for the user to install. Fix for issue #6479.

Source-Repo: https://github.com/servo/servo
Source-Revision: 3df35c2f42d7224560837a9ef63400e0e16829bf

servo/python/servo/build_commands.py

@@ -64,6 +64,7 @@ def notify_win(title, text):
 
 
 def notify_darwin(title, text):
+    try:
         import Foundation
         import objc
 
@@ -79,6 +80,8 @@ def notify_darwin(title, text):
 
         centre = NSUserNotificationCenter.defaultUserNotificationCenter()
         centre.scheduleNotification_(note)
+    except ImportError:
+        raise Exception("Please make sure that the Python pyobjc module is installed!")
 
 
 def notify_build_done(elapsed):