Closes #1840: [Napoleon] Fixes Google style parsing to only match section headers ending with exactly one colon

sphinx/ext/napoleon/docstring.py

@@ -23,7 +23,9 @@ from sphinx.util.pycompat import UnicodeMixin
 
 
 _directive_regex = re.compile(r'\.\. \S+::')
+_google_section_regex = re.compile(r'^(\s|\w)+:\s*$')
 _google_typed_arg_regex = re.compile(r'\s*(.+?)\s*\(\s*(.+?)\s*\)')
+_numpy_section_regex = re.compile(r'^[=\-`:\'"~^_*+#<>]{2,}\s*$')
 _xref_regex = re.compile(r'(:\w+:\S+:`.+?`|:\S+:`.+?`|`.+?`)')
 
 
@@ -381,7 +383,8 @@ class GoogleDocstring(UnicodeMixin):
 
     def _is_section_header(self):
         section = self._line_iter.peek().lower()
-        if section.strip(':') in self._sections:
+        match = _google_section_regex.match(section)
+        if match and section.strip(':') in self._sections:
             header_indent = self._get_indent(section)
             section_indent = self._get_current_indent(peek_ahead=1)
             return section_indent > header_indent
@@ -769,8 +772,7 @@ class NumpyDocstring(GoogleDocstring):
         section, underline = self._line_iter.peek(2)
         section = section.lower()
         if section in self._sections and isinstance(underline, string_types):
-            pattern = r'[=\-`:\'"~^_*+#<>]{' + str(len(section)) + r'}$'
+            return bool(_numpy_section_regex.match(underline))
-            return bool(re.match(pattern, underline))
         elif self._directive_sections:
             if _directive_regex.match(section):
                 for directive_section in self._directive_sections:

tests/test_ext_napoleon_docstring.py

@@ -576,6 +576,60 @@ Code sample for usage::
         actual = str(GoogleDocstring(docstring))
         self.assertEqual(expected, actual)
 
+    def test_section_header_formatting(self):
+        docstrings = [("""
+Summary line
+
+Example:
+    Multiline reStructuredText
+    literal code block
+
+""", """
+Summary line
+
+.. rubric:: Example
+
+Multiline reStructuredText
+literal code block
+"""),
+                      ################################
+                      ("""
+Summary line
+
+Example::
+
+    Multiline reStructuredText
+    literal code block
+
+""", """
+Summary line
+
+Example::
+
+    Multiline reStructuredText
+    literal code block
+"""),
+                      ################################
+                      ("""
+Summary line
+
+:Example:
+
+    Multiline reStructuredText
+    literal code block
+
+""", """
+Summary line
+
+:Example:
+
+    Multiline reStructuredText
+    literal code block
+""")]
+        for docstring, expected in docstrings:
+            actual = str(GoogleDocstring(docstring))
+            self.assertEqual(expected, actual)
+
 
 class NumpyDocstringTest(BaseDocstringTest):
     docstrings = [(
@@ -1095,3 +1149,75 @@ Example Function
         app = mock.Mock()
         actual = str(NumpyDocstring(docstring, config, app, "method"))
         self.assertEqual(expected, actual)
+
+    def test_section_header_underline_length(self):
+        docstrings = [("""
+Summary line
+
+Example
+-
+Multiline example
+body
+
+""", """
+Summary line
+
+Example
+-
+Multiline example
+body
+"""),
+                      ################################
+                      ("""
+Summary line
+
+Example
+--
+Multiline example
+body
+
+""", """
+Summary line
+
+.. rubric:: Example
+
+Multiline example
+body
+"""),
+                      ################################
+                      ("""
+Summary line
+
+Example
+-------
+Multiline example
+body
+
+""", """
+Summary line
+
+.. rubric:: Example
+
+Multiline example
+body
+"""),
+                      ################################
+                      ("""
+Summary line
+
+Example
+------------
+Multiline example
+body
+
+""", """
+Summary line
+
+.. rubric:: Example
+
+Multiline example
+body
+""")]
+        for docstring, expected in docstrings:
+            actual = str(NumpyDocstring(docstring))
+            self.assertEqual(expected, actual)