From 91650d89c9bb53c78e22eb94a31edc5656faa0b5 Mon Sep 17 00:00:00 2001
From: Takeshi KOMIYA <i.tkomiya@gmail.com>
Date: Wed, 15 Aug 2018 01:42:07 +0900
Subject: [PATCH] Fix #5291: autodoc crashed by ForwardRef types

---
 CHANGES                    | 2 ++
 sphinx/util/inspect.py     | 4 ++++
 tests/test_util_inspect.py | 3 +++
 tests/typing_test_data.py  | 3 +++
 4 files changed, 12 insertions(+)

diff --git a/CHANGES b/CHANGES
index 2cdb52a6c..7472232da 100644
--- a/CHANGES
+++ b/CHANGES
@@ -28,6 +28,8 @@ Bugs fixed
   font with XeLaTeX/LuaLateX (refs: #5251)
 * #5280: autodoc: Fix wrong type annotations for complex typing
 * autodoc: Optional types are wrongly rendered
+* #5291: autodoc crashed by ForwardRef types
+
 
 Testing
 --------
diff --git a/sphinx/util/inspect.py b/sphinx/util/inspect.py
index c3fe0178d..64e93f267 100644
--- a/sphinx/util/inspect.py
+++ b/sphinx/util/inspect.py
@@ -477,6 +477,8 @@ class Signature(object):
                 qualname = annotation._name
             elif getattr(annotation, '__qualname__', None):
                 qualname = annotation.__qualname__
+            elif getattr(annotation, '__forward_arg__', None):
+                qualname = annotation.__forward_arg__
             else:
                 qualname = self.format_annotation(annotation.__origin__)  # ex. Union
         elif hasattr(annotation, '__qualname__'):
@@ -510,6 +512,8 @@ class Signature(object):
                 qualname = annotation._name
             elif getattr(annotation, '__qualname__', None):
                 qualname = annotation.__qualname__
+            elif getattr(annotation, '__forward_arg__', None):
+                qualname = annotation.__forward_arg__
             else:
                 qualname = self.format_annotation(annotation.__origin__)  # ex. Union
         elif hasattr(annotation, '__qualname__'):
diff --git a/tests/test_util_inspect.py b/tests/test_util_inspect.py
index 51c2d06e1..a48aedcf0 100644
--- a/tests/test_util_inspect.py
+++ b/tests/test_util_inspect.py
@@ -297,6 +297,9 @@ def test_Signature_annotations():
     sig = inspect.Signature(Node.children).format_args()
     assert sig == '(self) -> List[typing_test_data.Node]'
 
+    sig = inspect.Signature(Node.__init__).format_args()
+    assert sig == '(self, parent: Optional[Node]) -> None'
+
 
 def test_safe_getattr_with_default():
     class Foo(object):
diff --git a/tests/typing_test_data.py b/tests/typing_test_data.py
index 35064b042..5b161eac4 100644
--- a/tests/typing_test_data.py
+++ b/tests/typing_test_data.py
@@ -73,5 +73,8 @@ def f13() -> Optional[str]:
 
 
 class Node:
+    def __init__(self, parent: Optional['Node']) -> None:
+        pass
+
     def children(self) -> List['Node']:
         pass