From 34c374a1e1dad468869c8e5dc6fb2ea7b1d90c7e Mon Sep 17 00:00:00 2001
From: Lance Stout <lancestout@gmail.com>
Date: Fri, 17 Dec 2010 13:11:03 -0500
Subject: [PATCH] Make tests pass for catching exceptions.

May now use sys.excepthook to catch exceptions
from threaded handlers.
---
 sleekxmpp/stanza/rootstanza.py   |  2 +-
 sleekxmpp/xmlstream/xmlstream.py | 24 +++++++++++++++++++++
 tests/test_stream_exceptions.py  | 37 +++++++++++++++++++-------------
 3 files changed, 47 insertions(+), 16 deletions(-)

diff --git a/sleekxmpp/stanza/rootstanza.py b/sleekxmpp/stanza/rootstanza.py
index 777314b..8123c5f 100644
--- a/sleekxmpp/stanza/rootstanza.py
+++ b/sleekxmpp/stanza/rootstanza.py
@@ -64,7 +64,7 @@ class RootStanza(StanzaBase):
             log.exception('Error handling {%s}%s stanza' %
                           (self.namespace, self.name))
             # Finally raise the exception, so it can be handled (or not)
-            # at a higher level
+            # at a higher level by using sys.excepthook.
             raise e
 
 register_stanza_plugin(RootStanza, Error)
diff --git a/sleekxmpp/xmlstream/xmlstream.py b/sleekxmpp/xmlstream/xmlstream.py
index 2317f04..d5c1043 100644
--- a/sleekxmpp/xmlstream/xmlstream.py
+++ b/sleekxmpp/xmlstream/xmlstream.py
@@ -682,6 +682,7 @@ class XMLStream(object):
                         Event handlers and the send queue will be threaded
                         regardless of this parameter's value.
         """
+        self._thread_excepthook()
         self.scheduler.process(threaded=True)
 
         def start_thread(name, target):
@@ -954,3 +955,26 @@ class XMLStream(object):
             self.disconnect()
             self.event_queue.put(('quit', None, None))
             return
+
+    def _thread_excepthook(self):
+        """
+        If a threaded event handler raises an exception, there is no way to
+        catch it except with an excepthook. Currently, each thread has its own
+        excepthook, but ideally we could use the main sys.excepthook.
+
+        Modifies threading.Thread to use sys.excepthook when an exception
+        is not caught.
+        """
+        init_old = threading.Thread.__init__
+        def init(self, *args, **kwargs):
+            init_old(self, *args, **kwargs)
+            run_old = self.run
+            def run_with_except_hook(*args, **kw):
+                try:
+                    run_old(*args, **kw)
+                except (KeyboardInterrupt, SystemExit):
+                    raise
+                except:
+                    sys.excepthook(*sys.exc_info())
+            self.run = run_with_except_hook
+        threading.Thread.__init__ = init
diff --git a/tests/test_stream_exceptions.py b/tests/test_stream_exceptions.py
index b7be648..e1b70d3 100644
--- a/tests/test_stream_exceptions.py
+++ b/tests/test_stream_exceptions.py
@@ -10,6 +10,7 @@ class TestStreamExceptions(SleekTest):
     """
 
     def tearDown(self):
+        sys.excepthook = sys.__excepthook__
         self.stream_close()
 
     def testXMPPErrorException(self):
@@ -78,9 +79,16 @@ class TestStreamExceptions(SleekTest):
     def testUnknownException(self):
         """Test raising an generic exception in a threaded handler."""
 
+        raised_errors = []
+
         def message(msg):
             raise ValueError("Did something wrong")
 
+        def catch_error(*args, **kwargs):
+            raised_errors.append(True)
+
+        sys.excepthook = catch_error
+
         self.stream_start()
         self.xmpp.add_event_handler('message', message)
 
@@ -90,21 +98,20 @@ class TestStreamExceptions(SleekTest):
           </message>
         """)
 
-        if sys.version_info < (3, 0):
-            self.send("""
-              <message type="error">
-                <error type="cancel">
-                  <undefined-condition
-                      xmlns="urn:ietf:params:xml:ns:xmpp-stanzas" />
-                  <text xmlns="urn:ietf:params:xml:ns:xmpp-stanzas">
-                    SleekXMPP got into trouble.
-                  </text>
-                </error>
-              </message>
-            """)
-        else:
-            # Unfortunately, tracebacks do not make for very portable tests.
-            pass
+        self.send("""
+          <message type="error">
+            <error type="cancel">
+              <undefined-condition
+                  xmlns="urn:ietf:params:xml:ns:xmpp-stanzas" />
+              <text xmlns="urn:ietf:params:xml:ns:xmpp-stanzas">
+                SleekXMPP got into trouble.
+              </text>
+            </error>
+          </message>
+        """)
+
+        self.assertEqual(raised_errors, [True], "Exception was not raised: %s" % raised_errors)
+
 
 
 suite = unittest.TestLoader().loadTestsFromTestCase(TestStreamExceptions)