From b3affa6949d3858312a28ff75a8161bfaf5db8ee Mon Sep 17 00:00:00 2001
From: Takeshi KOMIYA <i.tkomiya@gmail.com>
Date: Sat, 13 Jun 2020 23:53:30 +0900
Subject: [PATCH 1/2] Fix autodoc: Show detailed warning when type_comment is
 mismatched (refs: #7807)

---
 CHANGES                            | 3 +++
 sphinx/ext/autodoc/type_comment.py | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/CHANGES b/CHANGES
index 4198395c6..5f8d82d4a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -13,6 +13,9 @@ Deprecated
 Features added
 --------------
 
+* #7807: autodoc: Show detailed warning when type_comment is mismatched with its
+  signature
+
 Bugs fixed
 ----------
 
diff --git a/sphinx/ext/autodoc/type_comment.py b/sphinx/ext/autodoc/type_comment.py
index e6a77f24d..7f11e3d12 100644
--- a/sphinx/ext/autodoc/type_comment.py
+++ b/sphinx/ext/autodoc/type_comment.py
@@ -128,6 +128,9 @@ def update_annotations_using_type_comments(app: Sphinx, obj: Any, bound_method:
 
             if 'return' not in obj.__annotations__:
                 obj.__annotations__['return'] = type_sig.return_annotation
+    except KeyError as exc:
+        logger.warning(__("Failed to update signature for %r: parameter not found: %s"),
+                       obj, exc)
     except NotImplementedError as exc:  # failed to ast.unparse()
         logger.warning(__("Failed to parse type_comment for %r: %s"), obj, exc)
 

From d77622ba79a0ce8381b484ea4756d1f52b5f7803 Mon Sep 17 00:00:00 2001
From: Takeshi KOMIYA <i.tkomiya@gmail.com>
Date: Sun, 14 Jun 2020 01:19:21 +0900
Subject: [PATCH 2/2] Fix #7807: autodoc: wrong signature is shown for the
 function using contextmanager

---
 CHANGES                                         |  1 +
 sphinx/util/inspect.py                          | 17 ++++++++++++++++-
 .../test-ext-autodoc/target/wrappedfunction.py  |  9 ++++++++-
 tests/test_ext_autodoc_autofunction.py          | 13 +++++++++++++
 4 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/CHANGES b/CHANGES
index 5f8d82d4a..e4467d7f1 100644
--- a/CHANGES
+++ b/CHANGES
@@ -21,6 +21,7 @@ Bugs fixed
 
 * #7808: autodoc: Warnings raised on variable and attribute type annotations
 * #7802: autodoc: EOFError is raised on parallel build
+* #7807: autodoc: wrong signature is shown for the function using contextmanager
 * #7812: autosummary: generates broken stub files if the target code contains
   an attribute and module that are same name
 * #7811: sphinx.util.inspect causes circular import problem
diff --git a/sphinx/util/inspect.py b/sphinx/util/inspect.py
index 206be1f9b..956dcd49e 100644
--- a/sphinx/util/inspect.py
+++ b/sphinx/util/inspect.py
@@ -9,6 +9,7 @@
 """
 
 import builtins
+import contextlib
 import enum
 import inspect
 import re
@@ -421,6 +422,17 @@ def is_builtin_class_method(obj: Any, attr_name: str) -> bool:
     return getattr(builtins, name, None) is cls
 
 
+def _should_unwrap(subject: Callable) -> bool:
+    """Check the function should be unwrapped on getting signature."""
+    if (safe_getattr(subject, '__globals__', None) and
+            subject.__globals__.get('__name__') == 'contextlib' and  # type: ignore
+            subject.__globals__.get('__file__') == contextlib.__file__):  # type: ignore
+        # contextmanger should be unwrapped
+        return True
+
+    return False
+
+
 def signature(subject: Callable, bound_method: bool = False, follow_wrapped: bool = False
               ) -> inspect.Signature:
     """Return a Signature object for the given *subject*.
@@ -431,7 +443,10 @@ def signature(subject: Callable, bound_method: bool = False, follow_wrapped: boo
     """
     try:
         try:
-            signature = inspect.signature(subject, follow_wrapped=follow_wrapped)
+            if _should_unwrap(subject):
+                signature = inspect.signature(subject)
+            else:
+                signature = inspect.signature(subject, follow_wrapped=follow_wrapped)
         except ValueError:
             # follow built-in wrappers up (ex. functools.lru_cache)
             signature = inspect.signature(subject)
diff --git a/tests/roots/test-ext-autodoc/target/wrappedfunction.py b/tests/roots/test-ext-autodoc/target/wrappedfunction.py
index ea872f086..0bd2d2069 100644
--- a/tests/roots/test-ext-autodoc/target/wrappedfunction.py
+++ b/tests/roots/test-ext-autodoc/target/wrappedfunction.py
@@ -1,8 +1,15 @@
-# for py32 or above
+from contextlib import contextmanager
 from functools import lru_cache
+from typing import Generator
 
 
 @lru_cache(maxsize=None)
 def slow_function(message, timeout):
     """This function is slow."""
     print(message)
+
+
+@contextmanager
+def feeling_good(x: int, y: int) -> Generator:
+    """You'll feel better in this context!"""
+    yield
diff --git a/tests/test_ext_autodoc_autofunction.py b/tests/test_ext_autodoc_autofunction.py
index b4be85019..579ad9f48 100644
--- a/tests/test_ext_autodoc_autofunction.py
+++ b/tests/test_ext_autodoc_autofunction.py
@@ -146,3 +146,16 @@ def test_wrapped_function(app):
         '   This function is slow.',
         '',
     ]
+
+
+@pytest.mark.sphinx('html', testroot='ext-autodoc')
+def test_wrapped_function_contextmanager(app):
+    actual = do_autodoc(app, 'function', 'target.wrappedfunction.feeling_good')
+    assert list(actual) == [
+        '',
+        '.. py:function:: feeling_good(x: int, y: int) -> Generator',
+        '   :module: target.wrappedfunction',
+        '',
+        "   You'll feel better in this context!",
+        '',
+    ]