From dff45a11b7a49d13a5aa3b9845aff64a8f889a64 Mon Sep 17 00:00:00 2001
From: Takeshi KOMIYA <i.tkomiya@gmail.com>
Date: Sat, 16 May 2020 14:51:18 +0900
Subject: [PATCH] Fix #7668: autodoc: wrong retann value is passed to
 autodoc-proccess-signature

---
 CHANGES                        |  2 ++
 sphinx/ext/autodoc/__init__.py | 10 ++++++++--
 tests/test_ext_autodoc.py      | 22 +++++++++++++++++++++-
 3 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/CHANGES b/CHANGES
index 3ee4586a9..a799c249a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -90,6 +90,8 @@ Bugs fixed
 * #7362: autodoc: does not render correct signatures for built-in functions
 * #7654: autodoc: ``Optional[Union[foo, bar]]`` is presented as
   ``Union[foo, bar, None]``
+* #7668: autodoc: wrong retann value is passed to a handler of
+  autodoc-proccess-signature
 * #7551: autosummary: a nested class is indexed as non-nested class
 * #7535: sphinx-autogen: crashes when custom template uses inheritance
 * #7536: sphinx-autogen: crashes when template uses i18n feature
diff --git a/sphinx/ext/autodoc/__init__.py b/sphinx/ext/autodoc/__init__.py
index 80bcc0e8d..f81a53d02 100644
--- a/sphinx/ext/autodoc/__init__.py
+++ b/sphinx/ext/autodoc/__init__.py
@@ -389,21 +389,27 @@ class Documenter:
         if self.args is not None:
             # signature given explicitly
             args = "(%s)" % self.args
+            retann = self.retann
         else:
             # try to introspect the signature
             try:
+                retann = None
                 try:
                     args = self.format_args(**kwargs)
                 except TypeError:
                     # retry without arguments for old documenters
                     args = self.format_args()
+
+                if args:
+                    matched = re.match(r'^(\(.*\))\s+->\s+(.*)$', args)
+                    if matched:
+                        args = matched.group(1)
+                        retann = matched.group(2)
             except Exception:
                 logger.warning(__('error while formatting arguments for %s:') %
                                self.fullname, type='autodoc', exc_info=True)
                 args = None
 
-        retann = self.retann
-
         result = self.env.events.emit_firstresult('autodoc-process-signature',
                                                   self.objtype, self.fullname,
                                                   self.object, self.options, args, retann)
diff --git a/tests/test_ext_autodoc.py b/tests/test_ext_autodoc.py
index 76b970dbb..58a93dd22 100644
--- a/tests/test_ext_autodoc.py
+++ b/tests/test_ext_autodoc.py
@@ -161,7 +161,6 @@ def test_format_signature(app):
         pass
     assert formatsig('function', 'f', f, None, None) == '(a, b, c=1, **d)'
     assert formatsig('function', 'f', f, 'a, b, c, d', None) == '(a, b, c, d)'
-    assert formatsig('function', 'f', f, None, 'None') == '(a, b, c=1, **d) -> None'
     assert formatsig('function', 'g', g, None, None) == r"(a='\n')"
 
     # test for classes
@@ -246,6 +245,27 @@ def test_format_signature(app):
         '(b, c=42, *d, **e)'
 
 
+def test_autodoc_process_signature_typehints(app):
+    captured = []
+
+    def process_signature(*args):
+        captured.append(args)
+
+    app.connect('autodoc-process-signature', process_signature)
+
+    def func(x: int, y: int) -> int:
+        pass
+
+    directive = make_directive_bridge(app.env)
+    inst = app.registry.documenters['function'](directive, 'func')
+    inst.fullname = 'func'
+    inst.object = func
+    inst.objpath = ['func']
+    inst.format_signature()
+    assert captured == [(app, 'function', 'func', func,
+                         directive.genopt, '(x: int, y: int)', 'int')]
+
+
 def test_get_doc(app):
     directive = make_directive_bridge(app.env)