From cef2d95f7ed4c8ee97c986cc6adce403f2d06115 Mon Sep 17 00:00:00 2001
From: pharshalp <pharshalp@gmail.com>
Date: Mon, 10 Feb 2020 19:11:34 -0500
Subject: [PATCH] fix colorbar minorticks when
 rcParams['x/ytick.minor.visible'] = True

Added a test

Replaced the unnecessary logic with a one liner as suggested

Better docs for test

Removed random data from test

flake8 fix
---
 lib/matplotlib/colorbar.py            |  4 ++++
 lib/matplotlib/tests/test_colorbar.py | 28 +++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/lib/matplotlib/colorbar.py b/lib/matplotlib/colorbar.py
index 9e0110343e49..eb9511e0bb38 100644
--- a/lib/matplotlib/colorbar.py
+++ b/lib/matplotlib/colorbar.py
@@ -517,8 +517,12 @@ def _config_axis(self):
 
         if self.orientation == 'vertical':
             long_axis, short_axis = ax.yaxis, ax.xaxis
+            if mpl.rcParams['ytick.minor.visible']:
+                self.minorticks_on()
         else:
             long_axis, short_axis = ax.xaxis, ax.yaxis
+            if mpl.rcParams['xtick.minor.visible']:
+                self.minorticks_on()
 
         long_axis.set_label_position(self.ticklocation)
         long_axis.set_ticks_position(self.ticklocation)
diff --git a/lib/matplotlib/tests/test_colorbar.py b/lib/matplotlib/tests/test_colorbar.py
index 3ef5cbee62a6..eb2044e2f97d 100644
--- a/lib/matplotlib/tests/test_colorbar.py
+++ b/lib/matplotlib/tests/test_colorbar.py
@@ -327,6 +327,34 @@ def test_colorbar_minorticks_on_off():
     np.testing.assert_equal(cbar.ax.yaxis.get_minorticklocs(), [])
 
 
+def test_cbar_minorticks_for_rc_xyminortickvisible():
+    """
+    issue gh-16468.
+
+    Making sure that minor ticks on the colorbar are turned on
+    (internally) using the cbar.minorticks_on() method when
+    rcParams['xtick.minor.visible'] = True (for horizontal cbar)
+    rcParams['ytick.minor.visible'] = True (for vertical cbar).
+    Using cbar.minorticks_on() ensures that the minor ticks
+    don't overflow into the extend regions of the colorbar.
+    """
+
+    plt.rcParams['ytick.minor.visible'] = True
+    plt.rcParams['xtick.minor.visible'] = True
+
+    vmin, vmax = 0.4, 2.6
+    fig, ax = plt.subplots()
+    im = ax.pcolormesh([[1, 2]], vmin=vmin, vmax=vmax)
+
+    cbar = fig.colorbar(im, extend='both', orientation='vertical')
+    assert cbar.ax.yaxis.get_minorticklocs()[0] >= vmin
+    assert cbar.ax.yaxis.get_minorticklocs()[-1] <= vmax
+
+    cbar = fig.colorbar(im, extend='both', orientation='horizontal')
+    assert cbar.ax.xaxis.get_minorticklocs()[0] >= vmin
+    assert cbar.ax.xaxis.get_minorticklocs()[-1] <= vmax
+
+
 def test_colorbar_autoticks():
     # Test new autotick modes. Needs to be classic because
     # non-classic doesn't go this route.