Update AutoDateFormatter with locator

ImportanceOfBeingErnest · ImportanceOfBeingErnest · commit 9eda3db0cb36 · 2018-10-10T17:13:16.000+02:00
diff --git a/lib/matplotlib/axis.py b/lib/matplotlib/axis.py
@@ -1579,10 +1579,13 @@ def set_major_locator(self, locator):
         locator : ~matplotlib.ticker.Locator
         """
         if not isinstance(locator, mticker.Locator):
-            raise TypeError("formatter argument should be instance of "
+            raise TypeError("locator argument should be instance of "
                             "matplotlib.ticker.Locator")
         self.isDefault_majloc = False
         self.major.locator = locator
+        if (hasattr(self.get_major_formatter(), "_locator") and
+            hasattr(self.get_major_formatter(), "_tz")):
+            self.get_major_formatter()._locator = locator
         locator.set_axis(self)
         self.stale = True
 
@@ -1595,10 +1598,13 @@ def set_minor_locator(self, locator):
         locator : ~matplotlib.ticker.Locator
         """
         if not isinstance(locator, mticker.Locator):
-            raise TypeError("formatter argument should be instance of "
+            raise TypeError("locator argument should be instance of "
                             "matplotlib.ticker.Locator")
         self.isDefault_minloc = False
         self.minor.locator = locator
+        if (hasattr(self.get_minor_formatter(), "_locator") and
+            hasattr(self.get_minor_formatter(), "_tz")):
+            self.get_minor_formatter()._locator = locator
         locator.set_axis(self)
         self.stale = True
 
diff --git a/lib/matplotlib/tests/test_dates.py b/lib/matplotlib/tests/test_dates.py
@@ -220,6 +220,27 @@ def test_DateFormatter():
     fig.autofmt_xdate()
 
 
+def test_locator_set_formatter():
+    """
+    Test if setting the locator only will update the formatter to use
+    the new locator.
+    """
+    plt.rcParams["date.autoformatter.minute"] = "%d %H:%M"
+    t = [datetime.datetime(2018, 9, 30, 8, 0),
+         datetime.datetime(2018, 9, 30, 8, 59),
+         datetime.datetime(2018, 9, 30, 10, 30)]
+    x = [2, 3, 1]
+
+    fig, ax = plt.subplots()
+    ax.plot(t, x)
+    ax.xaxis.set_major_locator(mdates.MinuteLocator((0, 30)))
+    fig.canvas.draw()
+    ticklabels = [tl.get_text() for tl in ax.get_xticklabels()]
+    expected = ['30 08:00', '30 08:30', '30 09:00',
+                '30 09:30', '30 10:00', '30 10:30']
+    assert ticklabels == expected
+
+
 def test_date_formatter_strftime():
     """
     Tests that DateFormatter matches datetime.strftime,
