From 974fee39262e00a6eeec7bb5f5d5397c523adbf9 Mon Sep 17 00:00:00 2001
From: Marco Gorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Fri, 28 Feb 2025 18:09:13 +0000
Subject: [PATCH] type datetimeindex max/min reductions

---
 pandas-stubs/core/indexes/datetimelike.pyi | 18 ++++++++++++++----
 tests/test_indexes.py                      |  8 ++++++++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/pandas-stubs/core/indexes/datetimelike.pyi b/pandas-stubs/core/indexes/datetimelike.pyi
index fb27fae21..8ff1ae144 100644
--- a/pandas-stubs/core/indexes/datetimelike.pyi
+++ b/pandas-stubs/core/indexes/datetimelike.pyi
@@ -1,3 +1,4 @@
+import numpy as np
 from pandas.core.indexes.extension import ExtensionIndex
 from pandas.core.indexes.timedeltas import TimedeltaIndex
 from typing_extensions import Self
@@ -5,6 +6,7 @@ from typing_extensions import Self
 from pandas._libs.tslibs import BaseOffset
 from pandas._typing import (
     S1,
+    AxisIndex,
     TimeUnit,
 )
 
@@ -15,10 +17,18 @@ class DatetimeIndexOpsMixin(ExtensionIndex[S1]):
     def freqstr(self) -> str | None: ...
     @property
     def is_all_dates(self) -> bool: ...
-    def min(self, axis=..., skipna: bool = ..., *args, **kwargs): ...
-    def argmin(self, axis=..., skipna: bool = ..., *args, **kwargs): ...
-    def max(self, axis=..., skipna: bool = ..., *args, **kwargs): ...
-    def argmax(self, axis=..., skipna: bool = ..., *args, **kwargs): ...
+    def min(
+        self, axis: AxisIndex | None = ..., skipna: bool = ..., *args, **kwargs
+    ) -> S1: ...
+    def argmin(
+        self, axis: AxisIndex | None = ..., skipna: bool = ..., *args, **kwargs
+    ) -> np.int64: ...
+    def max(
+        self, axis: AxisIndex | None = ..., skipna: bool = ..., *args, **kwargs
+    ) -> S1: ...
+    def argmax(
+        self, axis: AxisIndex | None = ..., skipna: bool = ..., *args, **kwargs
+    ) -> np.int64: ...
     def __rsub__(  # type: ignore[override] # pyright: ignore[reportIncompatibleMethodOverride]
         self, other: DatetimeIndexOpsMixin
     ) -> TimedeltaIndex: ...
diff --git a/tests/test_indexes.py b/tests/test_indexes.py
index e77371cfb..b6becf357 100644
--- a/tests/test_indexes.py
+++ b/tests/test_indexes.py
@@ -1201,3 +1201,11 @@ def test_disallow_empty_index() -> None:
     # From GH 826
     if TYPE_CHECKING_INVALID_USAGE:
         i0 = pd.Index()  # type: ignore[call-overload] # pyright: ignore[reportCallIssue]
+
+
+def test_datetime_index_max_min_reductions() -> None:
+    dtidx = pd.DatetimeIndex(["2020-01-01", "2020-01-02"])
+    check(assert_type(dtidx.argmax(), np.int64), np.int64)
+    check(assert_type(dtidx.argmin(), np.int64), np.int64)
+    check(assert_type(dtidx.max(), pd.Timestamp), pd.Timestamp)
+    check(assert_type(dtidx.min(), pd.Timestamp), pd.Timestamp)