Use format_annotation to render class attribute type annotations (#299)

Resolves #298

src/sphinx_autodoc_typehints/__init__.py

@@ -18,6 +18,7 @@
 from sphinx.util.inspect import signature as sphinx_signature
 from sphinx.util.inspect import stringify_signature
 
+from .attributes_patch import patch_attribute_handling
 from .version import __version__
 
 _LOGGER = logging.getLogger(__name__)
@@ -732,6 +733,7 @@ def setup(app: Sphinx) -> dict[str, bool]:
     app.connect("autodoc-process-signature", process_signature)
     app.connect("autodoc-process-docstring", process_docstring)
     fix_autodoc_typehints_for_overloaded_methods()
+    patch_attribute_handling(app)
     return {"parallel_read_safe": True}
 
 

src/sphinx_autodoc_typehints/attributes_patch.py

@@ -0,0 +1,92 @@
+from functools import partial
+from optparse import Values
+from typing import Any, Tuple
+from unittest.mock import patch
+
+import sphinx.domains.python
+import sphinx.ext.autodoc
+from docutils.parsers.rst import Parser as RstParser
+from docutils.utils import new_document
+from sphinx.addnodes import desc_signature
+from sphinx.application import Sphinx
+from sphinx.domains.python import PyAttribute
+from sphinx.ext.autodoc import AttributeDocumenter
+
+# Defensively check for the things we want to patch
+_parse_annotation = getattr(sphinx.domains.python, "_parse_annotation", None)
+
+# We want to patch:
+# * sphinx.ext.autodoc.stringify_typehint (in sphinx < 6.1)
+# * sphinx.ext.autodoc.stringify_annotation (in sphinx >= 6.1)
+STRINGIFY_PATCH_TARGET = ""
+for target in ["stringify_typehint", "stringify_annotation"]:
+    if hasattr(sphinx.ext.autodoc, target):
+        STRINGIFY_PATCH_TARGET = f"sphinx.ext.autodoc.{target}"
+        break
+
+# If we didn't locate both patch targets, we will just do nothing.
+OKAY_TO_PATCH = bool(_parse_annotation and STRINGIFY_PATCH_TARGET)
+
+# A label we inject to the type string so we know not to try to treat it as a
+# type annotation
+TYPE_IS_RST_LABEL = "--is-rst--"
+
+
+orig_add_directive_header = AttributeDocumenter.add_directive_header
+orig_handle_signature = PyAttribute.handle_signature
+
+
+def stringify_annotation(app: Sphinx, annotation: Any, mode: str = "") -> str:  # noqa: U100
+    """Format the annotation with sphinx-autodoc-typehints and inject our
+    magic prefix to tell our patched PyAttribute.handle_signature to treat
+    it as rst."""
+    from . import format_annotation
+
+    return TYPE_IS_RST_LABEL + format_annotation(annotation, app.config)
+
+
+def patch_attribute_documenter(app: Sphinx) -> None:
+    """Instead of using stringify_typehint in
+    `AttributeDocumenter.add_directive_header`, use `format_annotation`
+    """
+
+    def add_directive_header(*args: Any, **kwargs: Any) -> Any:
+        with patch(STRINGIFY_PATCH_TARGET, partial(stringify_annotation, app)):
+            return orig_add_directive_header(*args, **kwargs)
+
+    AttributeDocumenter.add_directive_header = add_directive_header  # type:ignore[assignment]
+
+
+def rst_to_docutils(settings: Values, rst: str) -> Any:
+    """Convert rst to a sequence of docutils nodes"""
+    doc = new_document("", settings)
+    RstParser().parse(rst, doc)
+    # Remove top level paragraph node so that there is no line break.
+    return doc.children[0].children
+
+
+def patched_parse_annotation(settings: Values, typ: str, env: Any) -> Any:
+    # if typ doesn't start with our label, use original function
+    if not typ.startswith(TYPE_IS_RST_LABEL):
+        return _parse_annotation(typ, env)  # type: ignore
+    # Otherwise handle as rst
+    typ = typ[len(TYPE_IS_RST_LABEL) :]
+    return rst_to_docutils(settings, typ)
+
+
+def patched_handle_signature(self: PyAttribute, sig: str, signode: desc_signature) -> Tuple[str, str]:
+    target = "sphinx.domains.python._parse_annotation"
+    new_func = partial(patched_parse_annotation, self.state.document.settings)
+    with patch(target, new_func):
+        return orig_handle_signature(self, sig, signode)
+
+
+def patch_attribute_handling(app: Sphinx) -> None:
+    """Use format_signature to format class attribute type annotations"""
+    if not OKAY_TO_PATCH:
+        return
+    PyAttribute.handle_signature = patched_handle_signature  # type:ignore[assignment]
+    patch_attribute_documenter(app)
+
+
+__all__ = ["patch_attribute_handling"]

tests/roots/test-dummy/dummy_module.py

@@ -1,5 +1,6 @@
 from dataclasses import dataclass
 from mailbox import Mailbox
+from types import CodeType
 from typing import Callable, Optional, Union, overload
 
 
@@ -309,3 +310,10 @@ def func_with_overload(a: Union[int, str], b: Union[int, str]) -> None:  # noqa:
     b:
         The second thing
     """
+
+
+class TestClassAttributeDocs:
+    """A class"""
+
+    code: Union[CodeType, None]
+    """An attribute"""

tests/roots/test-dummy/index.rst

@@ -42,3 +42,6 @@ Dummy Module
 .. autofunction:: dummy_module.func_with_examples
 
 .. autofunction:: dummy_module.func_with_overload
+
+.. autoclass:: dummy_module.TestClassAttributeDocs
+   :members:

tests/test_sphinx_autodoc_typehints.py

@@ -782,6 +782,14 @@ class dummy_module.DataClass(x)
 
            Return type:
               "None"
+
+        class dummy_module.TestClassAttributeDocs
+
+           A class
+
+           code: "Optional"["CodeType"]
+
+              An attribute
         """
         expected_contents = dedent(expected_contents).format(**format_args).replace("–", "--")
         assert text_contents == maybe_fix_py310(expected_contents)

whitelist.txt

@@ -1,3 +1,4 @@
+addnodes
 ast3
 autodoc
 autouse
@@ -9,9 +10,11 @@ cpython
 csv
 dedent
 delattr
+desc
 dirname
 docnames
 Documenter
+docutils
 dunder
 eval
 exc
@@ -41,6 +44,7 @@ nptyping
 param
 parametrized
 params
+parsers
 pathlib
 pos
 prepend
@@ -49,8 +53,11 @@ pydata
 pytestconfig
 qualname
 rootdir
+rst
 rtype
 runtime
+sig
+signode
 skipif
 sph
 sphobjinv
@@ -63,9 +70,11 @@ supertype
 tempdir
 testroot
 textwrap
+typ
 typehint
 typehints
 unittest
 unresolvable
 util
+utils
 vararg