Merge branch 'main' into enh-latex-centering

Author: parthava-adabala

doc/source/whatsnew/v3.0.0.rst

@@ -1044,6 +1044,7 @@ Interval
 - :meth:`Index.is_monotonic_decreasing`, :meth:`Index.is_monotonic_increasing`, and :meth:`Index.is_unique` could incorrectly be ``False`` for an ``Index`` created from a slice of another ``Index``. (:issue:`57911`)
 - Bug in :class:`Index`, :class:`Series`, :class:`DataFrame` constructors when given a sequence of :class:`Interval` subclass objects casting them to :class:`Interval` (:issue:`46945`)
 - Bug in :func:`interval_range` where start and end numeric types were always cast to 64 bit (:issue:`57268`)
+- Bug in :meth:`IntervalIndex.get_indexer` and :meth:`IntervalIndex.drop` when one of the sides of the index is non-unique (:issue:`52245`)
 
 Indexing
 ^^^^^^^^

pandas/core/indexes/interval.py

@@ -712,7 +712,10 @@ def _get_indexer(
             # -> at most one match per interval in target
             # want exact matches -> need both left/right to match, so defer to
             # left/right get_indexer, compare elementwise, equality -> match
-            indexer = self._get_indexer_unique_sides(target)
+            if self.left.is_unique and self.right.is_unique:
+                indexer = self._get_indexer_unique_sides(target)
+            else:
+                indexer = self._get_indexer_pointwise(target)[0]
 
         elif not (is_object_dtype(target.dtype) or is_string_dtype(target.dtype)):
             # homogeneous scalar index: use IntervalTree