From 0e8ac5fbf4f839744893af1e17112c967fc0b34c Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Wed, 17 Oct 2018 09:17:14 -0700
Subject: [PATCH 1/3] validate min/max axis closes #23081

---
 pandas/compat/numpy/function.py      | 19 +++++++++++++++++++
 pandas/core/indexes/datetimelike.py  |  4 ++++
 pandas/tests/indexes/datetimelike.py | 12 ++++++++++++
 3 files changed, 35 insertions(+)

diff --git a/pandas/compat/numpy/function.py b/pandas/compat/numpy/function.py
index d42be56963569..b737a4ac4265d 100644
--- a/pandas/compat/numpy/function.py
+++ b/pandas/compat/numpy/function.py
@@ -360,3 +360,22 @@ def validate_resampler_func(method, args, kwargs):
                 "{func}() instead".format(func=method)))
         else:
             raise TypeError("too many arguments passed in")
+
+
+def validate_minmax_axis(axis):
+    """
+    Ensure that the axis argument passed to min, max, argmin, or argmax is
+    zero or None, as otherwise it will be incorrectly ignored.
+     Parameters
+    ----------
+    axis : int or None
+     Raises
+    ------
+    ValueError
+    """
+    ndim = 1  # hard-coded for Index
+    if axis is None:
+        return
+    if axis >= ndim or (axis < 0 and ndim + axis < 0):
+        raise ValueError("`axis` must be fewer than the number of "
+                         "dimensions ({ndim})".format(ndim=ndim))
diff --git a/pandas/core/indexes/datetimelike.py b/pandas/core/indexes/datetimelike.py
index 8e919ba3599fc..d9152c50309eb 100644
--- a/pandas/core/indexes/datetimelike.py
+++ b/pandas/core/indexes/datetimelike.py
@@ -431,6 +431,7 @@ def min(self, axis=None, *args, **kwargs):
         numpy.ndarray.min
         """
         nv.validate_min(args, kwargs)
+        nv.validate_minmax_axis(axis)
 
         try:
             i8 = self.asi8
@@ -459,6 +460,7 @@ def argmin(self, axis=None, *args, **kwargs):
         numpy.ndarray.argmin
         """
         nv.validate_argmin(args, kwargs)
+        nv.validate_minmax_axis(axis)
 
         i8 = self.asi8
         if self.hasnans:
@@ -479,6 +481,7 @@ def max(self, axis=None, *args, **kwargs):
         numpy.ndarray.max
         """
         nv.validate_max(args, kwargs)
+        nv.validate_minmax_axis(axis)
 
         try:
             i8 = self.asi8
@@ -507,6 +510,7 @@ def argmax(self, axis=None, *args, **kwargs):
         numpy.ndarray.argmax
         """
         nv.validate_argmax(args, kwargs)
+        nv.validate_minmax_axis(axis)
 
         i8 = self.asi8
         if self.hasnans:
diff --git a/pandas/tests/indexes/datetimelike.py b/pandas/tests/indexes/datetimelike.py
index e32e18ea0ec4a..7af8b259fa137 100644
--- a/pandas/tests/indexes/datetimelike.py
+++ b/pandas/tests/indexes/datetimelike.py
@@ -8,6 +8,18 @@
 
 class DatetimeLike(Base):
 
+    def test_argmax_axis_invalid(self):
+        # GH#23081
+        rng = self.create_index()
+        with pytest.raises(ValueError):
+            rng.argmax(axis=1)
+        with pytest.raises(ValueError):
+            rng.argmin(axis=2)
+        with pytest.raises(ValueError):
+            rng.min(axis=-2)
+        with pytest.raises(ValueError):
+            rng.max(axis=-3)
+
     def test_can_hold_identifiers(self):
         idx = self.create_index()
         key = idx[0]

From 1ef07f01262e6cff8bf3a9409c118d2c61f924f6 Mon Sep 17 00:00:00 2001
From: Tom Augspurger <TomAugspurger@users.noreply.github.com>
Date: Wed, 17 Oct 2018 19:15:39 -0700
Subject: [PATCH 2/3] Fix copy/paste indentation mistake

---
 pandas/compat/numpy/function.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/pandas/compat/numpy/function.py b/pandas/compat/numpy/function.py
index b737a4ac4265d..bc3e253d44e67 100644
--- a/pandas/compat/numpy/function.py
+++ b/pandas/compat/numpy/function.py
@@ -366,7 +366,13 @@ def validate_minmax_axis(axis):
     """
     Ensure that the axis argument passed to min, max, argmin, or argmax is
     zero or None, as otherwise it will be incorrectly ignored.
-     Parameters
+    Parameters
+    ----------
+    axis : int or None
+    
+    Raises
+    ------
+    ValueError
     ----------
     axis : int or None
      Raises

From b8302b3fbb647324387b717f8b1b4f0f52090c3d Mon Sep 17 00:00:00 2001
From: Brock Mendel <jbrockmendel@gmail.com>
Date: Wed, 17 Oct 2018 19:17:18 -0700
Subject: [PATCH 3/3] Fix merge mixup

---
 pandas/compat/numpy/function.py | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/pandas/compat/numpy/function.py b/pandas/compat/numpy/function.py
index bc3e253d44e67..a4232ca2ebf78 100644
--- a/pandas/compat/numpy/function.py
+++ b/pandas/compat/numpy/function.py
@@ -366,18 +366,14 @@ def validate_minmax_axis(axis):
     """
     Ensure that the axis argument passed to min, max, argmin, or argmax is
     zero or None, as otherwise it will be incorrectly ignored.
+
     Parameters
     ----------
     axis : int or None
-    
+
     Raises
     ------
     ValueError
-    ----------
-    axis : int or None
-     Raises
-    ------
-    ValueError
     """
     ndim = 1  # hard-coded for Index
     if axis is None: