utils.signal: made send_catch_log function more robust (by using pydispatch.robust.sendRobust) and added unittests

scrapy/tests/test_utils_signal.py

@@ -0,0 +1,42 @@
+import unittest
+
+from scrapy.xlib.pydispatch import dispatcher
+from scrapy.utils.signal import send_catch_log
+from scrapy import log
+
+test_signal = object()
+
+class SignalUtilsTest(unittest.TestCase):
+
+    def test_send_catch_log(self):
+        handlers_called = set()
+
+        def test_handler_error(arg):
+            handlers_called.add(test_handler_error)
+            a = 1/0
+
+        def test_handler_check(arg):
+            handlers_called.add(test_handler_check)
+            assert arg == 'test'
+
+        def log_received(message, level):
+            handlers_called.add(log_received)
+            assert "test_handler_error" in message
+            assert level == log.ERROR
+
+        dispatcher.connect(log_received, signal=log.logmessage_received)
+        dispatcher.connect(test_handler_error, signal=test_signal)
+        dispatcher.connect(test_handler_check, signal=test_signal)
+        send_catch_log(test_signal, arg='test')
+
+        assert test_handler_error in handlers_called
+        assert test_handler_check in handlers_called
+        assert log_received in handlers_called
+
+        dispatcher.disconnect(log_received, signal=log.logmessage_received)
+        dispatcher.disconnect(test_handler_error, signal=test_signal)
+        dispatcher.disconnect(test_handler_check, signal=test_signal)
+
+
+if __name__ == "__main__":
+    unittest.main()

scrapy/utils/signal.py

@@ -1,13 +1,14 @@
 """Helper functinos for working with signals"""
 
 from scrapy.xlib.pydispatch import dispatcher
+from scrapy.xlib.pydispatch.robust import sendRobust
 from scrapy import log
 
 def send_catch_log(*args, **kwargs):
-    """Same as dispatcher.send but logs any exceptions raised by the signal
-    handlers
+    """Same as dispatcher.robust.sendRobust but logs any exceptions raised by
+    the signal handlers
     """
-    try:
-        dispatcher.send(*args, **kwargs)
-    except:
-        log.exc("Exception catched on signal dispatch")
+    for receiver, result in sendRobust(*args, **kwargs):
+        if isinstance(result, Exception):
+            log.msg("Exception caught on signal dispatch: receiver=%r, " \
+                " exception=%r" % (receiver, result), level=log.ERROR)