FIX: add check for py3.5 to fail if naive datetime

jklymak · jklymak · commit dadeae6c40ec · 2018-10-31T08:27:18.000-07:00
diff --git a/lib/matplotlib/dates.py b/lib/matplotlib/dates.py
@@ -1411,7 +1411,14 @@ def tick_values(self, vmin, vmax):
         ymin = self.base.le(vmin.year) * self.base.step
         ymax = self.base.ge(vmax.year) * self.base.step
 
-        ticks = [vmin.replace(year=ymin, **self.replaced).astimezone(self.tz)]
+        vmin = vmin.replace(year=ymin, **self.replaced)
+        try:
+            ticks = [vmin.astimezone(self.tz)]
+        except ValueError:
+            raise ValueError('naive datetime objects cannot be used '
+                             'with matplotlib for python < 3.6; '
+                             'astimezone() cannot '
+                             'be applied to a naive datetime.')
         while True:
             dt = ticks[-1]
             if dt.year >= ymax:
