BUG: Index with duplicate labels raises ValueError in Dataframe.query

pandas/core/frame.py

@@ -9,6 +9,7 @@
 labeling information
 """
 from __future__ import annotations
+from pandas.core.indexes.range import RangeIndex
 
 import collections
 from collections import abc
@@ -4330,7 +4331,7 @@ def query(self, expr: str, *, inplace: Literal[True], **kwargs) -> None:
     def query(self, expr: str, *, inplace: bool = ..., **kwargs) -> DataFrame | None:
         ...
 
-    def query(self, expr: str, *, inplace: bool = False, **kwargs) -> DataFrame | None:
+    def query(self,expr: str, *,inplace: bool = False, **kwargs) -> DataFrame | None:
         """
         Query the columns of a DataFrame with a boolean expression.
 
@@ -4467,16 +4468,34 @@ def query(self, expr: str, *, inplace: bool = False, **kwargs) -> DataFrame | No
            A   B  C C
         0  1  10   10
         """
+
         inplace = validate_bool_kwarg(inplace, "inplace")
         if not isinstance(expr, str):
             msg = f"expr must be a string to be evaluated, {type(expr)} given"
             raise ValueError(msg)
         kwargs["level"] = kwargs.pop("level", 0) + 1
         kwargs["target"] = None
-        res = self.eval(expr, **kwargs)
 
+        if self.index.duplicated().any():
+            engine='numexpr'
+            # Create a copy of the dataframe with a unique index to avoid reindexing errors
+            unique_index = RangeIndex(len(self.index))
+            df_copy = self.copy()
+            df_copy.index = unique_index
+
+            # Filter the copied dataframe
+            filtered_df = df_copy.query(expr, engine=engine)
+
+            # Map the filtered index back to the original index labels
+            index_mapping = dict(zip(unique_index, self.index))
+            filtered_df.index = filtered_df.index.map(index_mapping)
+
+            return filtered_df
+
+        res = self.eval(expr, **kwargs)
         try:
             result = self.loc[res]
+
         except ValueError:
             # when res is multi-dimensional loc raises, but this is sometimes a
             # valid query