Napoleon: Unify the type preprocessing logic

Previously, there were two type preprocessing functions:
`_convert_type_spec` (used in Google-style docstrings) and
`_convert_numpy_type_spec` (used in Numpy-style docstrings).

The Google version simply applied type-alias translations or wrapped
the text in a `:py:class:` role.

The Numpy version does the same, plus adds special handling for keywords
`optional` and `default` and delimiter words `or`, `of`, and `and`. This
allows one to write in natural language, like `Array of int` instead of
`Array[int]` or `Widget, optional` instead of `Optional[Widget]` or
`Widget | None`. Numpy style is described in full at:
https://numpydoc.readthedocs.io/en/latest/format.html#parameters

This commit eliminates the distinction and allows Google-style
docstrings to use these preprocessing rules.

sphinx/ext/napoleon/docstring.py

@@ -154,7 +154,7 @@ def postprocess(item: str) -> list[str]:
     return tokens
 
 
-def _token_type(token: str, location: str | None = None) -> str:
+def _token_type(token: str, debug_location: str | None = None) -> str:
     def is_numeric(token: str) -> bool:
         try:
             # use complex to make sure every numeric value is detected as literal
@@ -177,28 +177,28 @@ def is_numeric(token: str) -> bool:
         logger.warning(
             __('invalid value set (missing closing brace): %s'),
             token,
-            location=location,
+            location=debug_location,
         )
         type_ = 'literal'
     elif token.endswith('}'):
         logger.warning(
             __('invalid value set (missing opening brace): %s'),
             token,
-            location=location,
+            location=debug_location,
         )
         type_ = 'literal'
     elif token.startswith(("'", '"')):
         logger.warning(
             __('malformed string literal (missing closing quote): %s'),
             token,
-            location=location,
+            location=debug_location,
         )
         type_ = 'literal'
     elif token.endswith(("'", '"')):
         logger.warning(
             __('malformed string literal (missing opening quote): %s'),
             token,
-            location=location,
+            location=debug_location,
         )
         type_ = 'literal'
     elif token in {'optional', 'default'}:
@@ -213,10 +213,10 @@ def is_numeric(token: str) -> bool:
     return type_
 
 
-def _convert_numpy_type_spec(
+def _convert_type_spec(
     _type: str,
-    location: str | None = None,
     translations: dict[str, str] | None = None,
+    debug_location: str | None = None,
 ) -> str:
     if translations is None:
         translations = {}
@@ -240,7 +240,7 @@ def convert_obj(
 
     tokens = _tokenize_type_spec(_type)
     combined_tokens = _recombine_set_tokens(tokens)
-    types = [(token, _token_type(token, location)) for token in combined_tokens]
+    types = [(token, _token_type(token, debug_location)) for token in combined_tokens]
 
     converters = {
         'literal': lambda x: '``%s``' % x,
@@ -258,15 +258,6 @@ def convert_obj(
     return converted
 
 
-def _convert_type_spec(_type: str, translations: dict[str, str] | None = None) -> str:
-    """Convert type specification to reference in reST."""
-    if translations is not None and _type in translations:
-        return translations[_type]
-    if _type == 'None':
-        return ':py:obj:`None`'
-    return f':py:class:`{_type}`'
-
-
 class GoogleDocstring:
     """Convert Google style docstrings to reStructuredText.
 
@@ -433,6 +424,20 @@ def __str__(self) -> str:
         """
         return '\n'.join(self.lines())
 
+    def _get_location(self) -> str | None:
+        try:
+            filepath = inspect.getfile(self._obj) if self._obj is not None else None
+        except TypeError:
+            filepath = None
+        name = self._name
+
+        if filepath is None and name is None:
+            return None
+        elif filepath is None:
+            filepath = ''
+
+        return f'{filepath}:docstring of {name}'
+
     def lines(self) -> list[str]:
         """Return the parsed lines of the docstring in reStructuredText format.
 
@@ -490,7 +495,11 @@ def _consume_field(
             _type, _name = _name, _type
 
         if _type and self._config.napoleon_preprocess_types:
-            _type = _convert_type_spec(_type, self._config.napoleon_type_aliases or {})
+            _type = _convert_type_spec(
+                _type,
+                translations=self._config.napoleon_type_aliases or {},
+                debug_location=self._get_location(),
+            )
 
         indent = self._get_indent(line) + 1
         _descs = [_desc, *self._dedent(self._consume_indented_block(indent))]
@@ -538,7 +547,9 @@ def _consume_returns_section(
 
             if _type and preprocess_types and self._config.napoleon_preprocess_types:
                 _type = _convert_type_spec(
-                    _type, self._config.napoleon_type_aliases or {}
+                    _type,
+                    translations=self._config.napoleon_type_aliases or {},
+                    debug_location=self._get_location(),
                 )
 
             _desc = self.__class__(_desc, self._config).lines()
@@ -1202,20 +1213,6 @@ def __init__(
         self._directive_sections = ['.. index::']
         super().__init__(docstring, config, app, what, name, obj, options)
 
-    def _get_location(self) -> str | None:
-        try:
-            filepath = inspect.getfile(self._obj) if self._obj is not None else None
-        except TypeError:
-            filepath = None
-        name = self._name
-
-        if filepath is None and name is None:
-            return None
-        elif filepath is None:
-            filepath = ''
-
-        return f'{filepath}:docstring of {name}'
-
     def _escape_args_and_kwargs(self, name: str) -> str:
         func = super()._escape_args_and_kwargs
 
@@ -1242,10 +1239,10 @@ def _consume_field(
             _type, _name = _name, _type
 
         if self._config.napoleon_preprocess_types:
-            _type = _convert_numpy_type_spec(
+            _type = _convert_type_spec(
                 _type,
-                location=self._get_location(),
                 translations=self._config.napoleon_type_aliases or {},
+                debug_location=self._get_location(),
             )
 
         indent = self._get_indent(line) + 1

tests/test_extensions/test_ext_napoleon_docstring.py

@@ -15,7 +15,7 @@
 from sphinx.ext.napoleon.docstring import (
     GoogleDocstring,
     NumpyDocstring,
-    _convert_numpy_type_spec,
+    _convert_type_spec,
     _recombine_set_tokens,
     _token_type,
     _tokenize_type_spec,
@@ -1330,7 +1330,7 @@ def test_preprocess_types(self):
         expected = """\
 Do as you please
 
-:Yields: :py:class:`str` -- Extended
+:Yields: :class:`str` -- Extended
 """
         assert str(actual) == expected
 
@@ -2675,7 +2675,7 @@ def test_convert_numpy_type_spec(self):
         )
 
         for spec, expected in zip(specs, converted, strict=True):
-            actual = _convert_numpy_type_spec(spec, translations=translations)
+            actual = _convert_type_spec(spec, translations=translations)
             assert actual == expected
 
     def test_parameter_types(self):