Correct UnboundLocalError

Occurs when jsonrpc method has PEP3107 annotations, and is called with
incorrect parameters.

jsonrpc/tests/test_pep3107.py

@@ -0,0 +1,23 @@
+import unittest
+from manager import JSONRPCResponseManager
+
+
+class TestJSONRPCResponseManager(unittest.TestCase):
+    def test_typeerror_with_annotations(self):
+        """If a function has Python3 annotations and is called with improper
+        arguments, make sure the framework doesn't fail with inspect.getargspec
+        """
+        def distance(a: float, b: float) -> float:
+            return (a**2 + b**2)**0.5
+
+        dispatcher = {
+            "distance": distance,
+        }
+
+        req = '{"jsonrpc": "2.0", "method": "distance", "params": [], "id": 3}'  # noqa
+        result = JSONRPCResponseManager.handle(req, dispatcher)
+
+        # Make sure this returns JSONRPCInvalidParams rather than raising
+        # UnboundLocalError
+        self.assertEqual(result.error['code'], -32602)
+

jsonrpc/utils.py

@@ -68,7 +68,12 @@ def is_invalid_params(func, *args, **kwargs):
     if not inspect.isfunction(func):
         return True
 
-    funcargs, varargs, varkwargs, defaults = inspect.getargspec(func)
+    try:
+        funcargs, varargs, varkwargs, defaults = inspect.getargspec(func)
+    except ValueError:
+        argspec = inspect.getfullargspec(func)
+        funcargs, varargs, varkwargs, defaults = argspec[:4]
+
     if defaults:
         funcargs = funcargs[:-len(defaults)]