Ignore extra argument type annotations

Closes #186

CHANGELOG.rst

@@ -11,6 +11,14 @@ Features
 * `#151 <https://github.com/readthedocs/sphinx-autoapi/issues/151>`: (Python) Added the ``autoapi_python_use_implicit_namespaces`` option to allow
   AutoAPI to search for implicit namespace packages.
 
+Bug Fixes
+^^^^^^^^^
+* `#186 <https://github.com/readthedocs/sphinx-autoapi/issues/186>`: (Python)
+  Fixed an exception when there are too many argument type annotations
+  in a type comment.
+  Instead, a warning is raised to indicate that the extra annotations
+  will be ignored.
+
 
 v1.2.1 (2019-10-9)
 ------------------

autoapi/mappers/python/astroid_utils.py

@@ -8,6 +8,9 @@ import sys
 
 import astroid
 import astroid.nodes
+import sphinx.util.logging
+
+_LOGGER = sphinx.util.logging.getLogger(__name__)
 
 
 if sys.version_info < (3,):
@@ -432,6 +435,13 @@ def format_args(args_node):
         result.append("/")
 
     if args_node.args:
+        if len(args_node.args) < len(annotations):
+            msg = "Ignoring extra argument type annotation(s) on {}".format(
+                args_node.scope().qname()
+            )
+            _LOGGER.warning(msg)
+            annotations = annotations[: len(args_node.args)]
+
         result.append(
             _format_args(args_node.args, positional_or_keyword_defaults, annotations)
         )

tests/python/pyannotationcommentsexample/example/example.py

@@ -39,3 +39,8 @@ class A:
 
 
 global_a = A()  # type: A
+
+
+def f3(first_arg, **kwargs):
+    # type: (first_arg, Any) -> None
+    """Annotation incorrectly leaves out `**`."""