add Sphinx extension to determine a class member's type

This is necessary to have return types for properties. See
discussion in scverse/mudata#130

Author: ilia-kats

{{cookiecutter.project_name}}/docs/_templates/autosummary/class.rst

@@ -39,7 +39,7 @@
     ~~~~~~~~~~
 
 {% endif %}
-    .. autoattribute:: {{ [fullname, item] | join(".") }}
+    .. auto{{ [fullname, item] | join(".") | member_type }}:: {{ [fullname, item] | join(".") }}
 {%- endfor %}
 {% endblock %}
 

{{cookiecutter.project_name}}/docs/extensions/member_type.py

@@ -0,0 +1,34 @@
+"""Extension adding a jinja2 filter that determines a class member’s type."""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Literal
+
+from jinja2.defaults import DEFAULT_FILTERS
+from jinja2.utils import import_string
+
+if TYPE_CHECKING:
+    from sphinx.application import Sphinx
+
+
+def member_type(obj_path: str) -> Literal["method", "property", "attribute"]:
+    """Determine object member type.
+
+    E.g.: `.. auto{{ '{{' }} fullname | member_type {{ '}}' }}::`
+    """
+    # https://jinja.palletsprojects.com/en/stable/api/#custom-filters
+    cls_path, member_name = obj_path.rsplit(".", 1)
+    cls = import_string(cls_path)
+    member = getattr(cls, member_name, None)
+    match member:
+        case property():
+            return "property"
+        case _ if callable(member):
+            return "method"
+        case _:
+            return "attribute"
+
+
+def setup(app: Sphinx):
+    """App setup hook."""
+    DEFAULT_FILTERS["member_type"] = member_type