From a99675bf78eec8024792da6448e89ea534c59b5a Mon Sep 17 00:00:00 2001
From: Takeshi KOMIYA <i.tkomiya@gmail.com>
Date: Thu, 30 Jul 2020 01:41:18 +0900
Subject: [PATCH] Fix #8008: py domain: failed to parse a type annotation
 containing ellipsis

Fix _parse_annotation() does not support a type annotation having ellipsis.
---
 CHANGES                  |  1 +
 sphinx/domains/python.py | 14 ++++++++++++++
 tests/test_domain_py.py  | 14 ++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/CHANGES b/CHANGES
index ff9236469..4da2823e9 100644
--- a/CHANGES
+++ b/CHANGES
@@ -69,6 +69,7 @@ Bugs fixed
 * #7691: linkcheck: HEAD requests are not used for checking
 * #4888: i18n: Failed to add an explicit title to ``:ref:`` role on translation
 * #7928: py domain: failed to resolve a type annotation for the attribute
+* #8008: py domain: failed to parse a type annotation containing ellipsis
 * #7994: std domain: option directive does not generate old node_id compatible
   with 2.x or older
 * #7968: i18n: The content of ``math`` directive is interpreted as reST on
diff --git a/sphinx/domains/python.py b/sphinx/domains/python.py
index fb167828f..f4bc58b69 100644
--- a/sphinx/domains/python.py
+++ b/sphinx/domains/python.py
@@ -11,6 +11,7 @@
 import builtins
 import inspect
 import re
+import sys
 import typing
 import warnings
 from inspect import Parameter
@@ -134,6 +135,19 @@ def _parse_annotation(annotation: str, env: BuildEnvironment = None) -> List[Nod
 
             return result
         else:
+            if sys.version_info >= (3, 6):
+                if isinstance(node, ast.Constant):
+                    if node.value is Ellipsis:
+                        return [addnodes.desc_sig_punctuation('', "...")]
+                    else:
+                        return [nodes.Text(node.value)]
+
+            if sys.version_info < (3, 8):
+                if isinstance(node, ast.Ellipsis):
+                    return [addnodes.desc_sig_punctuation('', "...")]
+                elif isinstance(node, ast.NameConstant):
+                    return [nodes.Text(node.value)]
+
             raise SyntaxError  # unsupported syntax
 
     if env is None:
diff --git a/tests/test_domain_py.py b/tests/test_domain_py.py
index ccf539b6d..b98f37912 100644
--- a/tests/test_domain_py.py
+++ b/tests/test_domain_py.py
@@ -262,6 +262,14 @@ def test_parse_annotation(app):
                           [desc_sig_punctuation, ")"],
                           [desc_sig_punctuation, "]"]))
 
+    doctree = _parse_annotation("Tuple[int, ...]", app.env)
+    assert_node(doctree, ([pending_xref, "Tuple"],
+                          [desc_sig_punctuation, "["],
+                          [pending_xref, "int"],
+                          [desc_sig_punctuation, ", "],
+                          [desc_sig_punctuation, "..."],
+                          [desc_sig_punctuation, "]"]))
+
     doctree = _parse_annotation("Callable[[int, int], int]", app.env)
     assert_node(doctree, ([pending_xref, "Callable"],
                           [desc_sig_punctuation, "["],
@@ -274,6 +282,12 @@ def test_parse_annotation(app):
                           [pending_xref, "int"],
                           [desc_sig_punctuation, "]"]))
 
+    doctree = _parse_annotation("List[None]", app.env)
+    assert_node(doctree, ([pending_xref, "List"],
+                          [desc_sig_punctuation, "["],
+                          [pending_xref, "None"],
+                          [desc_sig_punctuation, "]"]))
+
     # None type makes an object-reference (not a class reference)
     doctree = _parse_annotation("None", app.env)
     assert_node(doctree, ([pending_xref, "None"],))