Generate __slots__ dictionary with Sphinx-friendly docstrings

I have not worked out how to make the annotation really show up in generated Sphinx output. At least the docstring is there.

Author: clayote

src/attr/_make.py

@@ -10,6 +10,7 @@
 import itertools
 import linecache
 import sys
+import textwrap
 import types
 import unicodedata
 import weakref
@@ -893,14 +894,14 @@ def _create_slots_class(self):
 
         base_names = set(self._base_names)
 
-        names = self._attr_names
+        names = dict.fromkeys(self._attr_names)
         if (
             self._weakref_slot
             and "__weakref__" not in getattr(self._cls, "__slots__", ())
             and "__weakref__" not in names
             and not weakref_inherited
         ):
-            names += ("__weakref__",)
+            names["__weakref__"] = ""
 
         cached_properties = {
             name: cached_prop.func
@@ -915,11 +916,14 @@ def _create_slots_class(self):
             class_annotations = _get_annotations(self._cls)
             for name, func in cached_properties.items():
                 # Add cached properties to names for slotting.
-                names += (name,)
+                annotation = inspect.signature(func).return_annotation
+                doclines = [f".. :type: {annotation}"]
+                if func.__doc__ is not None:
+                    doclines.extend(textwrap.indent(textwrap.dedent(func.__doc__), "    ").splitlines())
+                names[name] = "\n".join(doclines)
                 # Clear out function from class to avoid clashing.
                 del cd[name]
                 additional_closure_functions_to_update.append(func)
-                annotation = inspect.signature(func).return_annotation
                 if annotation is not inspect.Parameter.empty:
                     class_annotations[name] = annotation
 
@@ -949,7 +953,7 @@ def _create_slots_class(self):
         if self._cache_hash:
             slot_names.append(_HASH_CACHE_FIELD)
 
-        cd["__slots__"] = tuple(slot_names)
+        cd["__slots__"] = {slot: names.get(slot, "") for slot in slot_names}
 
         cd["__qualname__"] = self._cls.__qualname__