Raise ValueError if slidermin/max incompatible.

heathhenley · heathhenley · commit 36ad9461f678 · 2017-02-23T00:12:03.000-05:00
diff --git a/lib/matplotlib/widgets.py b/lib/matplotlib/widgets.py
@@ -328,6 +328,13 @@ def __init__(self, ax, label, valmin, valmax, valinit=0.5, valfmt='%1.2f',
         """
         AxesWidget.__init__(self, ax)
 
+        if slidermin is not None and not hasattr(slidermin, 'val'):
+            raise ValueError("Argument slidermin ({}) has no 'val'"
+                             .format(type(slidermin)))
+        if slidermax is not None and not hasattr(slidermax, 'val'):
+            raise ValueError("Argument slidermax ({}) has no 'val'"
+                             .format(type(slidermax)))
+
         self.valmin = valmin
         self.valmax = valmax
         self.val = valinit
