matplotlib · tacaswell · Mar 22, 2015 · May 13, 2014 · May 26, 2014 · May 26, 2014
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -1978,19 +1978,19 @@ def make_iterable(x):
             if len(edgecolor) < nbars:
                 edgecolor *= nbars
 
-        # FIXME: convert the following to proper input validation
-        # raising ValueError; don't use assert for this.
-        assert len(left) == nbars, ("incompatible sizes: argument 'left' must "
-                                    "be length %d or scalar" % nbars)
-        assert len(height) == nbars, ("incompatible sizes: argument 'height' "
-                                      "must be length %d or scalar" %
-                                      nbars)
-        assert len(width) == nbars, ("incompatible sizes: argument 'width' "
-                                     "must be length %d or scalar" %
-                                     nbars)
-        assert len(bottom) == nbars, ("incompatible sizes: argument 'bottom' "
-                                      "must be length %d or scalar" %
-                                      nbars)
+        # input validation
+        if len(left) != nbars:
+            raise ValueError("incompatible sizes: argument 'left' must "
+                             "be length %d or scalar" % nbars)
+        if len(height) != nbars:
+            raise ValueError("incompatible sizes: argument 'height' "
+                              "must be length %d or scalar" % nbars)
+        if len(width) != nbars:
+            raise ValueError("incompatible sizes: argument 'width' "
+                             "must be length %d or scalar" % nbars)
+        if len(bottom) != nbars:
+            raise ValueError("incompatible sizes: argument 'bottom' "
+                             "must be length %d or scalar" % nbars)
 
         patches = []
 
@@ -2428,8 +2428,10 @@ def pie(self, x, explode=None, labels=None, colors=None,
             labels = [''] * len(x)
         if explode is None:
             explode = [0] * len(x)
-        assert(len(x) == len(labels))
-        assert(len(x) == len(explode))
+        if len(x) != len(labels):
+            raise ValueError("'label' must be of length 'x'")
+        if len(x) != len(explode):
+            raise ValueError("'explode' must be of length 'x'")
         if colors is None:
             colors = ('b', 'g', 'r', 'c', 'm', 'y', 'k', 'w')
 
@@ -3686,8 +3688,9 @@ def scatter(self, x, y, s=20, c=None, marker='o', cmap=None, norm=None,
         collection.update(kwargs)
 
         if colors is None:
-            if norm is not None:
-                assert(isinstance(norm, mcolors.Normalize))
+            if norm is not None and not isinstance(norm, mcolors.Normalize):
+                msg = "'norm' must be an instance of 'mcolors.Normalize'"
+                raise ValueError(msg)
             collection.set_array(np.asarray(c))
             collection.set_cmap(cmap)
             collection.set_norm(norm)
@@ -4057,8 +4060,9 @@ def hexbin(self, x, y, C=None, gridsize=100, bins=None,
             bins = np.sort(bins)
             accum = bins.searchsorted(accum)
 
-        if norm is not None:
-            assert(isinstance(norm, mcolors.Normalize))
+        if norm is not None and not isinstance(norm, mcolors.Normalize):
+            msg = "'norm' must be an instance of 'mcolors.Normalize'"
+            raise ValueError(msg)
         collection.set_array(accum)
         collection.set_cmap(cmap)
         collection.set_norm(norm)
@@ -4673,8 +4677,9 @@ def imshow(self, X, cmap=None, norm=None, aspect=None,
         if not self._hold:
             self.cla()
 
-        if norm is not None:
-            assert(isinstance(norm, mcolors.Normalize))
+        if norm is not None and not isinstance(norm, mcolors.Normalize):
+            msg = "'norm' must be an instance of 'mcolors.Normalize'"
+            raise ValueError(msg)
         if aspect is None:
             aspect = rcParams['image.aspect']
         self.set_aspect(aspect)
@@ -5000,8 +5005,9 @@ def pcolor(self, *args, **kwargs):
 
         collection.set_alpha(alpha)
         collection.set_array(C)
-        if norm is not None:
-            assert(isinstance(norm, mcolors.Normalize))
+        if norm is not None and not isinstance(norm, mcolors.Normalize):
+            msg = "'norm' must be an instance of 'mcolors.Normalize'"
+            raise ValueError(msg)
         collection.set_cmap(cmap)
         collection.set_norm(norm)
         collection.set_clim(vmin, vmax)
@@ -5149,8 +5155,9 @@ def pcolormesh(self, *args, **kwargs):
             antialiased=antialiased, shading=shading, **kwargs)
         collection.set_alpha(alpha)
         collection.set_array(C)
-        if norm is not None:
-            assert(isinstance(norm, mcolors.Normalize))
+        if norm is not None and not isinstance(norm, mcolors.Normalize):
+            msg = "'norm' must be an instance of 'mcolors.Normalize'"
+            raise ValueError(msg)
         collection.set_cmap(cmap)
         collection.set_norm(norm)
         collection.set_clim(vmin, vmax)
@@ -5274,8 +5281,9 @@ def pcolorfast(self, *args, **kwargs):
         cmap = kwargs.pop('cmap', None)
         vmin = kwargs.pop('vmin', None)
         vmax = kwargs.pop('vmax', None)
-        if norm is not None:
-            assert(isinstance(norm, mcolors.Normalize))
+        if norm is not None and not isinstance(norm, mcolors.Normalize):
+            msg = "'norm' must be an instance of 'mcolors.Normalize'"
+            raise ValueError(msg)
 
         C = args[-1]
         nr, nc = C.shape

diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -2104,7 +2104,10 @@ def draw_artist(self, a):
         caches the renderer.  It is used to efficiently update Axes
         data (axis ticks, labels, etc are not updated)
         """
-        assert self._cachedRenderer is not None
+        if self._cachedRenderer is None:
+            msg = ('draw_artist can only be used after an initial draw which'
+                   ' caches the render')
+            raise AttributeError(msg)
         a.draw(self._cachedRenderer)
 
     def redraw_in_frame(self):
@@ -2113,7 +2116,10 @@ def redraw_in_frame(self):
         caches the renderer.  It is used to efficiently update Axes
         data (axis ticks, labels, etc are not updated)
         """
-        assert self._cachedRenderer is not None
+        if self._cachedRenderer is None:
+            msg = ('redraw_in_frame can only be used after an initial draw'
+                   ' which caches the render')
+            raise AttributeError(msg)
         self.draw(self._cachedRenderer, inframe=True)
 
     def get_renderer_cache(self):

diff --git a/lib/matplotlib/axis.py b/lib/matplotlib/axis.py
@@ -1728,11 +1728,13 @@ def set_label_position(self, position):
 
         ACCEPTS: [ 'top' | 'bottom' ]
         """
-        assert position == 'top' or position == 'bottom'
         if position == 'top':
             self.label.set_verticalalignment('baseline')
-        else:
+        elif position == 'bottom':
             self.label.set_verticalalignment('top')
+        else:
+            msg = "Position accepts only [ 'top' | 'bottom' ]"
+            raise ValueError(msg)
         self.label_position = position
 
     def _update_label_position(self, bboxes, bboxes2):
@@ -2032,13 +2034,15 @@ def set_label_position(self, position):
 
         ACCEPTS: [ 'left' | 'right' ]
         """
-        assert position == 'left' or position == 'right'
         self.label.set_rotation_mode('anchor')
         self.label.set_horizontalalignment('center')
         if position == 'left':
             self.label.set_verticalalignment('bottom')
-        else:
+        elif position == 'right':
             self.label.set_verticalalignment('top')
+        else:
+            msg = "Position accepts only [ 'left' | 'right' ]"
+            raise ValueError(msg)
         self.label_position = position
 
     def _update_label_position(self, bboxes, bboxes2):
@@ -2083,13 +2087,14 @@ def _update_offset_text_position(self, bboxes, bboxes2):
         )
 
     def set_offset_position(self, position):
-        assert position == 'left' or position == 'right'
-
         x, y = self.offsetText.get_position()
         if position == 'left':
             x = 0
-        else:
+        elif position == 'right':
             x = 1
+        else:
+            msg = "Position accepts only [ 'left' | 'right' ]"
+            raise ValueError(msg)
 
         self.offsetText.set_ha(position)
         self.offsetText.set_position((x, y))

diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -969,7 +969,11 @@ def set_clip_path(self, path):
         Set the clip path and transformation.  Path should be a
         :class:`~matplotlib.transforms.TransformedPath` instance.
         """
-        assert path is None or isinstance(path, transforms.TransformedPath)
+        if path is not None and not isinstance(path,
+                transforms.TransformedPath):
+            msg = ("Path should be a matplotlib.transforms.TransformedPath"
+                   "instance.")
+            raise ValueError(msg)
         self._clippath = path
 
     def set_dashes(self, dash_offset, dash_list):

diff --git a/lib/matplotlib/blocking_input.py b/lib/matplotlib/blocking_input.py
@@ -30,6 +30,8 @@
 from matplotlib.cbook import is_sequence_of_strings
 import matplotlib.lines as mlines
 
+import warnings
+
 
 class BlockingInput(object):
     """
@@ -38,8 +40,8 @@ class BlockingInput(object):
     """
     def __init__(self, fig, eventslist=()):
         self.fig = fig
-        assert is_sequence_of_strings(
-            eventslist), "Requires a sequence of event name strings"
+        if not is_sequence_of_strings(eventslist):
+            raise ValueError("Requires a sequence of event name strings")
         self.eventslist = eventslist
 
     def on_event(self, event):
@@ -95,7 +97,8 @@ def __call__(self, n=1, timeout=30):
         Blocking call to retrieve n events
         """
 
-        assert isinstance(n, int), "Requires an integer argument"
+        if not isinstance(n, int):
+            raise ValueError("Requires an integer argument")
         self.n = n
 
         self.events = []
@@ -146,9 +149,9 @@ def post_event(self):
         """
         This will be called to process events
         """
-        assert len(self.events) > 0, "No events yet"
-
-        if self.events[-1].name == 'key_press_event':
+        if len(self.events) == 0:
+            warnings.warn("No events yet")
+        elif self.events[-1].name == 'key_press_event':
             self.key_event()
         else:
             self.mouse_event()
@@ -359,9 +362,10 @@ def post_event(self):
         """
         Determines if it is a key event
         """
-        assert len(self.events) > 0, "No events yet"
-
-        self.keyormouse = self.events[-1].name == 'key_press_event'
+        if len(self.events) == 0:
+            warnings.warn("No events yet")
+        else:
+            self.keyormouse = self.events[-1].name == 'key_press_event'
 
     def __call__(self, timeout=30):
         """

diff --git a/lib/matplotlib/contour.py b/lib/matplotlib/contour.py
@@ -857,10 +857,12 @@ def __init__(self, ax, *args, **kwargs):
         else:
             self.logscale = False
 
-        if self.origin is not None:
-            assert(self.origin in ['lower', 'upper', 'image'])
-        if self.extent is not None:
-            assert(len(self.extent) == 4)
+        if self.origin not in [None, 'lower', 'upper', 'image']:
+            raise ValueError("If given, *origin* must be one of [ 'lower' |"
+                             " 'upper' | 'image']")
+        if self.extent is not None and len(self.extent) != 4:
+            raise ValueError("If given, *extent* must be '[ *None* |"
+                             " (x0,x1,y0,y1) ]'")
         if self.colors is not None and cmap is not None:
             raise ValueError('Either colors or cmap must be None')
         if self.origin == 'image':

diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -872,7 +872,9 @@ def add_axes(self, *args, **kwargs):
 
         if isinstance(args[0], Axes):
             a = args[0]
-            assert(a.get_figure() is self)
+            if a.get_figure() is not self:
+                msg = "The Axes must have been created in the present figure"
+                raise ValueError(msg)
         else:
             rect = args[0]
             projection_class, kwargs, key = process_projection_requirements(
@@ -946,7 +948,10 @@ def add_subplot(self, *args, **kwargs):
         if isinstance(args[0], SubplotBase):
 
             a = args[0]
-            assert(a.get_figure() is self)
+            if a.get_figure() is not self:
+                msg = ("The Subplot must have been created in the present"
+                       " figure")
+                raise ValueError(msg)
             # make a key for the subplot (which includes the axes object id
             # in the hash)
             key = self._make_key(*args, **kwargs)
@@ -1104,7 +1109,10 @@ def draw_artist(self, a):
         draw :class:`matplotlib.artist.Artist` instance *a* only --
         this is available only after the figure is drawn
         """
-        assert self._cachedRenderer is not None
+        if self._cachedRenderer is None:
+            msg = ('draw_artist can only be used after an initial draw which'
+                   ' caches the render')
+            raise AttributeError(msg)
         a.draw(self._cachedRenderer)
 
     def get_axes(self):