FIX-#7113: Fix docstring overrides for subclasses.

modin/tests/config/docs_module/classes.py

@@ -30,3 +30,6 @@
     def apply():
         """This is a test of the documentation module for BasePandasDataSet.apply."""
         return
+
+    def astype():
+        """This is a test of the documentation module for BasePandasDataSet.astype."""

modin/tests/config/test_envvars.py

@@ -12,6 +12,7 @@
 # governing permissions and limitations under the License.
 
 import os
+import sys
 
 import pandas
 import pytest
@@ -96,6 +97,13 @@ def test_overrides(self):
         assert BasePandasDataset.apply.__doc__ == (
             "This is a test of the documentation module for BasePandasDataSet.apply."
         )
+        # Test scenario 2 from https://github.com/modin-project/modin/issues/7113:
+        # We can correctly override the docstring for BasePandasDataset.astype,
+        # which is the same method as Series.astype.
+        assert pd.Series.astype is BasePandasDataset.astype
+        assert BasePandasDataset.astype.__doc__ == (
+            "This is a test of the documentation module for BasePandasDataSet.astype."
+        )
         assert (
             pd.DataFrame.apply.__doc__
             == "This is a test of the documentation module for DataFrame."
@@ -130,6 +138,16 @@ def test_not_redefining_classes_modin_issue_7138(self):
 
         assert pd.DataFrame is original_dataframe_class
 
+    def test_base_docstring_override_with_no_dataframe_or_series_class_issue_7113(
+        self,
+    ):
+        # This test case tests scenario 1 from issue 7113.
+        sys.path.append(f"{os.path.dirname(__file__)}")
+        cfg.DocModule.put("docs_module_with_just_base")
+        assert BasePandasDataset.astype.__doc__ == (
+            "This is a test of the documentation module for BasePandasDataSet.astype."
+        )
+
 
 @pytest.mark.skipif(cfg.Engine.get() != "Ray", reason="Ray specific test")
 def test_ray_cluster_resources():

modin/utils.py

@@ -384,6 +384,13 @@ def _replace_doc(
 # inherited docstrings.
 _docstring_inheritance_calls: list[Callable[[str], None]] = []
 
+# This is a set of (class, attribute_name) pairs whose docstrings we have
+# already replaced since we last updated DocModule. Note that we don't store
+# the attributes themselves since we replace property attributes instead of
+# modifying them in place:
+# https://github.com/modin-project/modin/blob/e9dbcc127913db77473a83936e8b6bb94ef84f0d/modin/utils.py#L353
+_attributes_with_docstrings_replaced: set[tuple[type, str]] = set()
+
 
 def _documentable_obj(obj: object) -> bool:
     """
@@ -417,6 +424,7 @@ def _update_inherited_docstrings(doc_module: DocModule) -> None:
     doc_module : DocModule
         The current DocModule.
     """
+    _attributes_with_docstrings_replaced.clear()
     _doc_module = doc_module.get()
     for doc_inheritance_call in _docstring_inheritance_calls:
         doc_inheritance_call(doc_module=_doc_module)  # type: ignore[call-arg]
@@ -488,7 +496,8 @@ def _inherit_docstrings_in_place(
             if base is object:
                 continue
             for attr, obj in base.__dict__.items():
-                if attr in seen:
+                # only replace docstrings once to prevent https://github.com/modin-project/modin/issues/7113
+                if attr in seen or (base, attr) in _attributes_with_docstrings_replaced:
                     continue
                 seen.add(attr)
                 # Try to get the attribute from the docs class first, then
@@ -511,6 +520,8 @@ def _inherit_docstrings_in_place(
                     attr_name=attr,
                 )
 
+                _attributes_with_docstrings_replaced.add((base, attr))
+
 
 def _inherit_docstrings(
     parent: object,