Make unmap throw more verbose exception

Author: DrLuke

pythonosc/dispatcher.py

@@ -86,10 +86,14 @@ def unmap(self, address: str, handler: FunctionType, *args, needs_reply_address:
     pass
 
   def unmap(self, address, handler, *args, needs_reply_address=False):
-    if isinstance(handler, Handler):
-      self._map[address].remove(handler)
-    else:
-      self._map[address].remove(Handler(handler, list(args), needs_reply_address))
+    try:
+      if isinstance(handler, Handler):
+        self._map[address].remove(handler)
+      else:
+        self._map[address].remove(Handler(handler, list(args), needs_reply_address))
+    except ValueError as e:
+      if str(e) == "list.remove(x): x not in list":
+        raise ValueError("Address '%s' doesn't have handler '%s' mapped to it" % (address, handler)) from e
 
   def handlers_for_address(self, address_pattern):
     """yields Handler namedtuples matching the given OSC pattern."""

pythonosc/test/test_dispatcher.py

@@ -137,5 +137,16 @@ def dummyhandler():
     self.dispatcher.unmap("/map/me/too", dummyhandler)
     self.sortAndAssertSequenceEqual([], self.dispatcher.handlers_for_address("/map/me/too"))
 
+  def test_unmap_exception(self):
+    def dummyhandler():
+        pass
+
+    with self.assertRaises(ValueError) as context:
+      self.dispatcher.unmap("/unmap/exception", dummyhandler)
+
+    handlerobj = self.dispatcher.map("/unmap/somethingelse", dummyhandler())
+    with self.assertRaises(ValueError) as context:
+      self.dispatcher.unmap("/unmap/exception", handlerobj)
+
 if __name__ == "__main__":
   unittest.main()