Fix unexpected __doc__ values (#2556)

* fix unexpected '__doc__' values

some '__doc__' fields of standard library
   symbols (e.g. WrapperDescriptorType.__doc__) don't return a string,
   they return a 'getset_descriptor'. Thus, an attempt to print "as
   string" fails. The solution is to check that __doc__ is an instance
   of str.

Note that it wasn't uncovered by the tests due to classes not being
   attached to their parent in some cases. This is be done in one of
   the subsequent commits.

it's a part of the campaign to get rid of non-module roots

* put the "temporary_class" for the metaclass hack into adhoc module

it's a part of the campaign to get rid of non-module roots

Author: temyurchenko

astroid/nodes/node_classes.py

@@ -2061,7 +2061,16 @@ def __init__(
         :param end_col_offset: The end column this node appears on in the
             source code. Note: This is after the last symbol.
         """
-        self.value: Any = value
+        if getattr(value, "__name__", None) == "__doc__":
+            warnings.warn(  # pragma: no cover
+                "You have most likely called a __doc__ field of some object "
+                "and it didn't return a string. "
+                "That happens to some symbols from the standard library. "
+                "Check for isinstance(<X>.__doc__, str).",
+                RuntimeWarning,
+                stacklevel=0,
+            )
+        self.value = value
         """The value that the constant represents."""
 
         self.kind: str | None = kind  # can be None

astroid/nodes/scoped_nodes/scoped_nodes.py

@@ -1624,7 +1624,7 @@ def infer_call_result(
                     col_offset=0,
                     end_lineno=0,
                     end_col_offset=0,
-                    parent=self,
+                    parent=AstroidManager().adhoc_module,
                 )
                 new_class.hide = True
                 new_class.postinit(

astroid/raw_building.py

@@ -56,7 +56,8 @@ def _add_dunder_class(func, member) -> None:
     if not cls_name:
         return
     cls_bases = [ancestor.__name__ for ancestor in python_cls.__bases__]
-    ast_klass = build_class(cls_name, cls_bases, python_cls.__doc__)
+    doc = python_cls.__doc__ if isinstance(python_cls.__doc__, str) else None
+    ast_klass = build_class(cls_name, cls_bases, doc)
     func.instance_attrs["__class__"] = [ast_klass]
 
 
@@ -316,7 +317,7 @@ def object_build_function(
         args,
         posonlyargs,
         defaults,
-        member.__doc__,
+        member.__doc__ if isinstance(member.__doc__, str) else None,
         kwonlyargs=kwonlyargs,
         kwonlydefaults=kwonly_defaults,
     )
@@ -357,11 +358,8 @@ def _base_class_object_build(
     """
     class_name = name or getattr(member, "__name__", None) or localname
     assert isinstance(class_name, str)
-    klass = build_class(
-        class_name,
-        basenames,
-        member.__doc__,
-    )
+    doc = member.__doc__ if isinstance(member.__doc__, str) else None
+    klass = build_class(class_name, basenames, doc)
     klass._newstyle = isinstance(member, type)
     node.add_local_node(klass, localname)
     try:
@@ -718,11 +716,12 @@ def _astroid_bootstrapping() -> None:
                 parent=nodes.Unknown(),
             )
             klass.parent = astroid_builtin
+            doc = _type.__doc__ if isinstance(_type.__doc__, str) else None
             klass.postinit(
                 bases=[],
                 body=[],
                 decorators=None,
-                doc_node=nodes.Const(value=_type.__doc__) if _type.__doc__ else None,
+                doc_node=nodes.Const(doc) if doc else None,
             )
             builder.object_build(klass, _type)
             astroid_builtin[_type.__name__] = klass