Fix field renames after external class data writes

CHANGELOG.md

@@ -1,5 +1,6 @@
 # **Upcoming release**
 
+- Preserve same-module class data assignments and reject unsafe dependent renames (@yangfan-yf-yf)
 - #895 patchedast Starred and keyword now consumes their syntactically expected and ** (@lieryan)
 - #896 patchedast cleanup and refactoring (@lieryan)
 

docs/library.rst

@@ -617,6 +617,18 @@ Examples
 Rename
 ------
 
+Rope follows a single unconditional assignment such as ``Holder.value = Item()``
+when both classes are defined at module level in the same module and the value
+has ordinary data lookup behavior. Imported names in a class body retain their
+original source identity when the corresponding class attribute is replaced.
+
+Repeated or conditional writes, early or deferred reads, class rebinding,
+inheritance, and custom attribute lookup can leave the value uncertain. For
+these modeled writes, a potentially affected rename raises
+``rope.base.exceptions.RefactoringError`` before producing changes. This
+analysis is conservative and may refuse an otherwise safe rename; it does not
+infer arbitrary factories, descriptors, or dynamic cross-module assignments.
+
 Using rename refactoring:
 
 .. code-block:: python

rope/base/evaluate.py

@@ -103,6 +103,22 @@ def get_primary_and_pyname_at(
             elif isinstance(pyobject, pyobjects.AbstractFunction):
                 parameter_name = rope.base.pynames.ParameterName()
                 return (None, parameter_name)
+        # A class data overlay must not replace the imported source symbol.
+        if holding_scope.get_kind() == "Class":
+            from rope.base import externaldata
+
+            imported = externaldata.import_source_name(
+                holding_scope,
+                lineno,
+                offset,
+                self.worder.get_word_at(offset),
+                self.worder.get_primary_at(offset),
+                self.worder.get_from_module(offset),
+                self.worder.is_from_aliased(offset),
+                self.worder.is_from_statement_module(offset),
+            )
+            if imported is not None:
+                return (None, imported)
         # class body
         if self._is_defined_in_class_body(holding_scope, offset, lineno):
             class_scope = holding_scope