Use PEP 604 display for typing.Optional and typing.Union

doc/extdev/deprecated.rst

@@ -22,6 +22,11 @@ The following is a list of deprecated interfaces.
      - Removed
      - Alternatives
 
+   * - ``sphinx.util.typing.stringify``
+     - 6.1
+     - 8.0
+     - ``sphinx.util.typing.stringify_annotation``
+
    * - HTML 4 support
      - 5.2
      - 7.0

sphinx/domains/python.py

@@ -176,6 +176,8 @@ def unparse(node: ast.AST) -> list[Node]:
         elif isinstance(node, ast.Name):
             return [nodes.Text(node.id)]
         elif isinstance(node, ast.Subscript):
+            if getattr(node.value, 'id', '') in {'Optional', 'Union'}:
+                return _unparse_pep_604_annotation(node)
             result = unparse(node.value)
             result.append(addnodes.desc_sig_punctuation('', '['))
             result.extend(unparse(node.slice))
@@ -206,6 +208,28 @@ def unparse(node: ast.AST) -> list[Node]:
         else:
             raise SyntaxError  # unsupported syntax
 
+    def _unparse_pep_604_annotation(node: ast.Subscript) -> list[Node]:
+        subscript = node.slice
+        if isinstance(subscript, ast.Index):
+            # py38 only
+            subscript = subscript.value  # type: ignore[assignment]
+
+        flattened: list[Node] = []
+        if isinstance(subscript, ast.Tuple):
+            flattened.extend(unparse(subscript.elts[0]))
+            for elt in subscript.elts[1:]:
+                flattened.extend(unparse(ast.BitOr()))
+                flattened.extend(unparse(elt))
+        else:
+            # e.g. a Union[] inside an Optional[]
+            flattened.extend(unparse(subscript))
+
+        if getattr(node.value, 'id', '') == 'Optional':
+            flattened.extend(unparse(ast.BitOr()))
+            flattened.append(nodes.Text('None'))
+
+        return flattened
+
     try:
         tree = ast.parse(annotation, type_comments=True)
         result: list[Node] = []

sphinx/ext/autodoc/__init__.py

@@ -27,8 +27,7 @@
 from sphinx.util.docstrings import prepare_docstring, separate_metadata
 from sphinx.util.inspect import (evaluate_signature, getdoc, object_description, safe_getattr,
                                  stringify_signature)
-from sphinx.util.typing import OptionSpec, get_type_hints, restify
-from sphinx.util.typing import stringify as stringify_typehint
+from sphinx.util.typing import OptionSpec, get_type_hints, restify, stringify_annotation
 
 if TYPE_CHECKING:
     from sphinx.ext.autodoc.directive import DocumenterBridge
@@ -1902,9 +1901,10 @@ def update_content(self, more_content: StringList) -> None:
             attrs = [repr(self.object.__name__)]
             for constraint in self.object.__constraints__:
                 if self.config.autodoc_typehints_format == "short":
-                    attrs.append(stringify_typehint(constraint, "smart"))
+                    attrs.append(stringify_annotation(constraint, "smart"))
                 else:
-                    attrs.append(stringify_typehint(constraint))
+                    attrs.append(stringify_annotation(constraint,
+                                                      "fully-qualified-except-typing"))
             if self.object.__bound__:
                 if self.config.autodoc_typehints_format == "short":
                     bound = restify(self.object.__bound__, "smart")
@@ -2027,10 +2027,11 @@ def add_directive_header(self, sig: str) -> None:
                                              self.config.autodoc_type_aliases)
                 if self.objpath[-1] in annotations:
                     if self.config.autodoc_typehints_format == "short":
-                        objrepr = stringify_typehint(annotations.get(self.objpath[-1]),
-                                                     "smart")
+                        objrepr = stringify_annotation(annotations.get(self.objpath[-1]),
+                                                       "smart")
                     else:
-                        objrepr = stringify_typehint(annotations.get(self.objpath[-1]))
+                        objrepr = stringify_annotation(annotations.get(self.objpath[-1]),
+                                                       "fully-qualified-except-typing")
                     self.add_line('   :type: ' + objrepr, sourcename)
 
             try:
@@ -2622,10 +2623,11 @@ def add_directive_header(self, sig: str) -> None:
                                              self.config.autodoc_type_aliases)
                 if self.objpath[-1] in annotations:
                     if self.config.autodoc_typehints_format == "short":
-                        objrepr = stringify_typehint(annotations.get(self.objpath[-1]),
-                                                     "smart")
+                        objrepr = stringify_annotation(annotations.get(self.objpath[-1]),
+                                                       "smart")
                     else:
-                        objrepr = stringify_typehint(annotations.get(self.objpath[-1]))
+                        objrepr = stringify_annotation(annotations.get(self.objpath[-1]),
+                                                       "fully-qualified-except-typing")
                     self.add_line('   :type: ' + objrepr, sourcename)
 
             try:
@@ -2750,9 +2752,10 @@ def add_directive_header(self, sig: str) -> None:
                                               type_aliases=self.config.autodoc_type_aliases)
                 if signature.return_annotation is not Parameter.empty:
                     if self.config.autodoc_typehints_format == "short":
-                        objrepr = stringify_typehint(signature.return_annotation, "smart")
+                        objrepr = stringify_annotation(signature.return_annotation, "smart")
                     else:
-                        objrepr = stringify_typehint(signature.return_annotation)
+                        objrepr = stringify_annotation(signature.return_annotation,
+                                                       "fully-qualified-except-typing")
                     self.add_line('   :type: ' + objrepr, sourcename)
             except TypeError as exc:
                 logger.warning(__("Failed to get a function signature for %s: %s"),

sphinx/ext/autodoc/typehints.py

@@ -12,7 +12,8 @@
 import sphinx
 from sphinx import addnodes
 from sphinx.application import Sphinx
-from sphinx.util import inspect, typing
+from sphinx.util import inspect
+from sphinx.util.typing import stringify_annotation
 
 
 def record_typehints(app: Sphinx, objtype: str, name: str, obj: Any,
@@ -30,9 +31,9 @@ def record_typehints(app: Sphinx, objtype: str, name: str, obj: Any,
             sig = inspect.signature(obj, type_aliases=app.config.autodoc_type_aliases)
             for param in sig.parameters.values():
                 if param.annotation is not param.empty:
-                    annotation[param.name] = typing.stringify(param.annotation, mode)
+                    annotation[param.name] = stringify_annotation(param.annotation, mode)
             if sig.return_annotation is not sig.empty:
-                annotation['return'] = typing.stringify(sig.return_annotation, mode)
+                annotation['return'] = stringify_annotation(sig.return_annotation, mode)
     except (TypeError, ValueError):
         pass
 

sphinx/ext/napoleon/docstring.py

@@ -12,8 +12,7 @@
 from sphinx.config import Config as SphinxConfig
 from sphinx.locale import _, __
 from sphinx.util import logging
-from sphinx.util.inspect import stringify_annotation
-from sphinx.util.typing import get_type_hints
+from sphinx.util.typing import get_type_hints, stringify_annotation
 
 logger = logging.getLogger(__name__)
 
@@ -876,7 +875,8 @@ def _lookup_annotation(self, _name: str) -> str:
                                    ) or {})
                     self._annotations = get_type_hints(self._obj, None, localns)
                 if _name in self._annotations:
-                    return stringify_annotation(self._annotations[_name])
+                    return stringify_annotation(self._annotations[_name],
+                                                'fully-qualified-except-typing')
         # No annotation found
         return ""
 

sphinx/util/inspect.py

@@ -22,8 +22,7 @@
 
 from sphinx.pycode.ast import unparse as ast_unparse
 from sphinx.util import logging
-from sphinx.util.typing import ForwardRef
-from sphinx.util.typing import stringify as stringify_annotation
+from sphinx.util.typing import ForwardRef, stringify_annotation
 
 logger = logging.getLogger(__name__)
 

sphinx/util/typing.py

@@ -11,6 +11,8 @@
 from docutils import nodes
 from docutils.parsers.rst.states import Inliner
 
+from sphinx.deprecation import RemovedInSphinx80Warning, deprecated_alias
+
 try:
     from types import UnionType  # type: ignore  # python 3.10 or above
 except ImportError:
@@ -205,9 +207,14 @@ def restify(cls: type | None, mode: str = 'fully-qualified-except-typing') -> st
         return inspect.object_description(cls)
 
 
-def stringify(annotation: Any, mode: str = 'fully-qualified-except-typing') -> str:
+def stringify_annotation(
+    annotation: Any,
+    /,
+    mode: str = 'fully-qualified-except-typing',
+) -> str:
     """Stringify type annotation object.
 
+    :param annotation: The annotation to stringified.
     :param mode: Specify a method how annotations will be stringified.
 
                  'fully-qualified-except-typing'
@@ -219,12 +226,20 @@ def stringify(annotation: Any, mode: str = 'fully-qualified-except-typing') -> s
                      Show the module name and qualified name of the annotation.
     """
     from sphinx.ext.autodoc.mock import ismock, ismockmodule  # lazy loading
-    from sphinx.util import inspect  # lazy loading
+    from sphinx.util.inspect import isNewType  # lazy loading
+
+    if mode not in {'fully-qualified-except-typing', 'fully-qualified', 'smart'}:
+        raise ValueError("'mode' must be one of 'fully-qualified-except-typing', "
+                         f"'fully-qualified', or 'smart'; got {mode!r}.")
 
     if mode == 'smart':
-        modprefix = '~'
+        module_prefix = '~'
     else:
-        modprefix = ''
+        module_prefix = ''
+
+    annotation_qualname = getattr(annotation, '__qualname__', '')
+    annotation_module = getattr(annotation, '__module__', '')
+    annotation_name = getattr(annotation, '__name__', '')
 
     if isinstance(annotation, str):
         if annotation.startswith("'") and annotation.endswith("'"):
@@ -233,104 +248,105 @@ def stringify(annotation: Any, mode: str = 'fully-qualified-except-typing') -> s
         else:
             return annotation
     elif isinstance(annotation, TypeVar):
-        if (annotation.__module__ == 'typing' and
-                mode in ('fully-qualified-except-typing', 'smart')):
-            return annotation.__name__
+        if (annotation_module == 'typing'
+                and mode in {'fully-qualified-except-typing', 'smart'}):
+            return annotation_name
         else:
-            return modprefix + '.'.join([annotation.__module__, annotation.__name__])
-    elif inspect.isNewType(annotation):
+            return module_prefix + f'{annotation_module}.{annotation_name}'
+    elif isNewType(annotation):
         if sys.version_info[:2] >= (3, 10):
             # newtypes have correct module info since Python 3.10+
-            return modprefix + f'{annotation.__module__}.{annotation.__name__}'
+            return module_prefix + f'{annotation_module}.{annotation_name}'
         else:
-            return annotation.__name__
+            return annotation_name
     elif not annotation:
         return repr(annotation)
     elif annotation is NoneType:
         return 'None'
     elif ismockmodule(annotation):
-        return modprefix + annotation.__name__
+        return module_prefix + annotation_name
     elif ismock(annotation):
-        return modprefix + f'{annotation.__module__}.{annotation.__name__}'
+        return module_prefix + f'{annotation_module}.{annotation_name}'
     elif is_invalid_builtin_class(annotation):
-        return modprefix + INVALID_BUILTIN_CLASSES[annotation]
+        return module_prefix + INVALID_BUILTIN_CLASSES[annotation]
     elif str(annotation).startswith('typing.Annotated'):  # for py310+
         pass
-    elif (getattr(annotation, '__module__', None) == 'builtins' and
-          getattr(annotation, '__qualname__', None)):
+    elif annotation_module == 'builtins' and annotation_qualname:
         if hasattr(annotation, '__args__'):  # PEP 585 generic
             return repr(annotation)
         else:
-            return annotation.__qualname__
+            return annotation_qualname
     elif annotation is Ellipsis:
         return '...'
 
-    module = getattr(annotation, '__module__', None)
-    modprefix = ''
-    if module == 'typing' and getattr(annotation, '__forward_arg__', None):
-        qualname = annotation.__forward_arg__
-    elif module == 'typing':
-        if getattr(annotation, '_name', None):
-            qualname = annotation._name
-        elif getattr(annotation, '__qualname__', None):
-            qualname = annotation.__qualname__
-        else:
-            qualname = stringify(annotation.__origin__).replace('typing.', '')  # ex. Union
-
+    module_prefix = ''
+    annotation_forward_arg = getattr(annotation, '__forward_arg__', None)
+    if (annotation_qualname
+            or (annotation_module == 'typing' and not annotation_forward_arg)):
         if mode == 'smart':
-            modprefix = '~%s.' % module
+            module_prefix = f'~{annotation_module}.'
         elif mode == 'fully-qualified':
-            modprefix = '%s.' % module
-    elif hasattr(annotation, '__qualname__'):
-        if mode == 'smart':
-            modprefix = '~%s.' % module
+            module_prefix = f'{annotation_module}.'
+        elif annotation_module != 'typing' and mode == 'fully-qualified-except-typing':
+            module_prefix = f'{annotation_module}.'
+
+    if annotation_module == 'typing':
+        if annotation_forward_arg:
+            # handle ForwardRefs
+            qualname = annotation_forward_arg
         else:
-            modprefix = '%s.' % module
-        qualname = annotation.__qualname__
+            _name = getattr(annotation, '_name', '')
+            if _name:
+                qualname = _name
+            elif annotation_qualname:
+                qualname = annotation_qualname
+            else:
+                qualname = stringify_annotation(
+                    annotation.__origin__, 'fully-qualified-except-typing'
+                ).replace('typing.', '')  # ex. Union
+    elif annotation_qualname:
+        qualname = annotation_qualname
     elif hasattr(annotation, '__origin__'):
         # instantiated generic provided by a user
-        qualname = stringify(annotation.__origin__, mode)
-    elif UnionType and isinstance(annotation, UnionType):  # types.Union (for py3.10+)
-        qualname = 'types.Union'
+        qualname = stringify_annotation(annotation.__origin__, mode)
+    elif UnionType and isinstance(annotation, UnionType):  # types.UnionType (for py3.10+)
+        qualname = 'types.UnionType'
     else:
         # we weren't able to extract the base type, appending arguments would
         # only make them appear twice
         return repr(annotation)
 
-    if getattr(annotation, '__args__', None):
-        if not isinstance(annotation.__args__, (list, tuple)):
+    annotation_args = getattr(annotation, '__args__', None)
+    if annotation_args:
+        if not isinstance(annotation_args, (list, tuple)):
             # broken __args__ found
             pass
-        elif qualname in ('Optional', 'Union'):
-            if len(annotation.__args__) > 1 and annotation.__args__[-1] is NoneType:
-                if len(annotation.__args__) > 2:
-                    args = ', '.join(stringify(a, mode) for a in annotation.__args__[:-1])
-                    return f'{modprefix}Optional[{modprefix}Union[{args}]]'
-                else:
-                    return f'{modprefix}Optional[{stringify(annotation.__args__[0], mode)}]'
-            else:
-                args = ', '.join(stringify(a, mode) for a in annotation.__args__)
-                return f'{modprefix}Union[{args}]'
-        elif qualname == 'types.Union':
-            if len(annotation.__args__) > 1 and None in annotation.__args__:
-                args = ' | '.join(stringify(a) for a in annotation.__args__ if a)
-                return f'{modprefix}Optional[{args}]'
-            else:
-                return ' | '.join(stringify(a) for a in annotation.__args__)
+        elif qualname in {'Optional', 'Union', 'types.UnionType'}:
+            return ' | '.join(stringify_annotation(a, mode) for a in annotation_args)
         elif qualname == 'Callable':
-            args = ', '.join(stringify(a, mode) for a in annotation.__args__[:-1])
-            returns = stringify(annotation.__args__[-1], mode)
-            return f'{modprefix}{qualname}[[{args}], {returns}]'
+            args = ', '.join(stringify_annotation(a, mode) for a in annotation_args[:-1])
+            returns = stringify_annotation(annotation_args[-1], mode)
+            return f'{module_prefix}Callable[[{args}], {returns}]'
         elif qualname == 'Literal':
-            args = ', '.join(repr(a) for a in annotation.__args__)
-            return f'{modprefix}{qualname}[{args}]'
+            args = ', '.join(repr(a) for a in annotation_args)
+            return f'{module_prefix}Literal[{args}]'
         elif str(annotation).startswith('typing.Annotated'):  # for py39+
-            return stringify(annotation.__args__[0], mode)
-        elif all(is_system_TypeVar(a) for a in annotation.__args__):
+            return stringify_annotation(annotation_args[0], mode)
+        elif all(is_system_TypeVar(a) for a in annotation_args):
             # Suppress arguments if all system defined TypeVars (ex. Dict[KT, VT])
-            return modprefix + qualname
+            return module_prefix + qualname
         else:
-            args = ', '.join(stringify(a, mode) for a in annotation.__args__)
-            return f'{modprefix}{qualname}[{args}]'
+            args = ', '.join(stringify_annotation(a, mode) for a in annotation_args)
+            return f'{module_prefix}{qualname}[{args}]'
+
+    return module_prefix + qualname
+
 
-    return modprefix + qualname
+deprecated_alias(__name__,
+                 {
+                     'stringify': stringify_annotation,
+                 },
+                 RemovedInSphinx80Warning,
+                 {
+                     'stringify': 'sphinx.util.typing.stringify_annotation',
+                 })