Revert "DEPR: Remove deprecation from private class IntervalTree (pandas-dev#47637)"

This reverts commit f6658ef.

Author: mroeschke

pandas/_libs/intervaltree.pxi.in

@@ -8,6 +8,8 @@ import warnings
 from pandas._libs import lib
 from pandas._libs.algos import is_monotonic
 
+from pandas._libs.interval import _warning_interval
+
 ctypedef fused int_scalar_t:
     int64_t
     float64_t
@@ -40,13 +42,18 @@ cdef class IntervalTree(IntervalMixin):
         object _is_overlapping, _left_sorter, _right_sorter
         Py_ssize_t _na_count
 
-    def __init__(self, left, right, inclusive: str | None = None, leaf_size=100):
+    def __init__(self, left, right, inclusive: str | None = None, closed: None | lib.NoDefault = lib.no_default, leaf_size=100):
         """
         Parameters
         ----------
         left, right : np.ndarray[ndim=1]
             Left and right bounds for each interval. Assumed to contain no
             NaNs.
+        closed : {'left', 'right', 'both', 'neither'}, optional
+            Whether the intervals are closed on the left-side, right-side, both
+            or neither. Defaults to 'right'.
+
+            .. deprecated:: 1.5.0
 
         inclusive : {"both", "neither", "left", "right"}, optional
             Whether the intervals are closed on the left-side, right-side, both
@@ -59,6 +66,8 @@ cdef class IntervalTree(IntervalMixin):
             to brute-force search. Tune this parameter to optimize query
             performance.
         """
+        inclusive, closed = _warning_interval(inclusive, closed)
+
         if inclusive is None:
             inclusive = "right"
 
@@ -110,7 +119,7 @@ cdef class IntervalTree(IntervalMixin):
         if self._is_overlapping is not None:
             return self._is_overlapping
 
-        # <= when inclusive on both sides since endpoints can overlap
+        # <= when both sides closed since endpoints can overlap
         op = le if self.inclusive == 'both' else lt
 
         # overlap if start of current interval < end of previous interval
@@ -254,7 +263,7 @@ cdef class IntervalNode:
 
 
 # we need specialized nodes and leaves to optimize for different dtype and
-# inclusive values
+# closed values
 
 {{py:
 

pandas/tests/indexes/interval/test_interval_tree.py

@@ -190,6 +190,24 @@ def test_construction_overflow(self):
         expected = (50 + np.iinfo(np.int64).max) / 2
         assert result == expected
 
+    def test_interval_tree_error_and_warning(self):
+        # GH 40245
+
+        msg = (
+            "Deprecated argument `closed` cannot "
+            "be passed if argument `inclusive` is not None"
+        )
+        with pytest.raises(ValueError, match=msg):
+            left, right = np.arange(10), [np.iinfo(np.int64).max] * 10
+            IntervalTree(left, right, closed="both", inclusive="both")
+
+        msg = "Argument `closed` is deprecated in favor of `inclusive`"
+        with tm.assert_produces_warning(
+            FutureWarning, match=msg, check_stacklevel=False
+        ):
+            left, right = np.arange(10), [np.iinfo(np.int64).max] * 10
+            IntervalTree(left, right, closed="both")
+
     @pytest.mark.xfail(not IS64, reason="GH 23440")
     @pytest.mark.parametrize(
         "left, right, expected",