Merge pull request #14879 from anntzer/scalevalidation

efiring · web-flow · commit d511ab8867f2 · 2019-07-29T10:16:55.000-10:00
Error out when unsupported kwargs are passed to Scale.
diff --git a/doc/api/next_api_changes/2019-07-24-AL.rst b/doc/api/next_api_changes/2019-07-24-AL.rst
@@ -0,0 +1,8 @@
+API changes
+```````````
+
+Passing unsupported keyword arguments to `.ScaleBase` and its subclasses
+`.LinearScale`, and `.SymLogScale` is deprecated and will raise a `TypeError` in 3.3.
+
+If extra kwargs are pased to `.LogScale`, `TypeError` will now be
+raised instead of `ValueError`.
diff --git a/lib/matplotlib/scale.py b/lib/matplotlib/scale.py
@@ -19,6 +19,7 @@
     NullLocator, LogLocator, AutoLocator, AutoMinorLocator,
     SymmetricalLogLocator, LogitLocator)
 from matplotlib.transforms import Transform, IdentityTransform
+from matplotlib.cbook import warn_deprecated
 
 
 class ScaleBase:
@@ -52,6 +53,14 @@ def __init__(self, axis, **kwargs):
         be used: a single scale object should be usable by multiple
         `~matplotlib.axis.Axis`\es at the same time.
         """
+        if kwargs:
+            warn_deprecated(
+                '3.2.0',
+                message=(
+                    f"ScaleBase got an unexpected keyword "
+                    f"argument {next(iter(kwargs))!r}. "
+                    'In the future this will raise TypeError')
+            )
 
     def get_transform(self):
         """
@@ -143,8 +152,7 @@ def forward(values: array-like) -> array-like
             self._forward = forward
             self._inverse = inverse
         else:
-            raise ValueError('arguments to FuncTransform must '
-                             'be functions')
+            raise ValueError('arguments to FuncTransform must be functions')
 
     def transform_non_affine(self, values):
         return self._forward(values)
@@ -382,16 +390,14 @@ def __init__(self, axis, **kwargs):
             nonpos = kwargs.pop('nonposy', 'clip')
             cbook._check_in_list(['mask', 'clip'], nonposy=nonpos)
 
-        if len(kwargs):
-            raise ValueError(("provided too many kwargs, can only pass "
-                              "{'basex', 'subsx', nonposx'} or "
-                              "{'basey', 'subsy', nonposy'}.  You passed ") +
-                             "{!r}".format(kwargs))
+        if kwargs:
+            raise TypeError(f"LogScale got an unexpected keyword "
+                            f"argument {next(iter(kwargs))!r}")
 
         if base <= 0 or base == 1:
             raise ValueError('The log base cannot be <= 0 or == 1')
 
-        self._transform = self.LogTransform(base, nonpos)
+        self._transform = LogTransform(base, nonpos)
         self.subs = subs
 
     @property
@@ -566,6 +572,16 @@ def __init__(self, axis, **kwargs):
             linthresh = kwargs.pop('linthreshy', 2.0)
             subs = kwargs.pop('subsy', None)
             linscale = kwargs.pop('linscaley', 1.0)
+        if kwargs:
+            warn_deprecated(
+                '3.2.0',
+                message=(
+                    f"SymmetricalLogScale got an unexpected keyword "
+                    f"argument {next(iter(kwargs))!r}. "
+                    'In the future this will raise TypeError')
+            )
+            # raise TypeError(f"SymmetricalLogScale got an unexpected keyword "
+            #                 f"argument {next(iter(kwargs))!r}")
 
         if base <= 1.0:
             raise ValueError("'basex/basey' must be larger than 1")
@@ -574,10 +590,7 @@ def __init__(self, axis, **kwargs):
         if linscale <= 0.0:
             raise ValueError("'linscalex/linthreshy' must be positive")
 
-        self._transform = self.SymmetricalLogTransform(base,
-                                                       linthresh,
-                                                       linscale)
-
+        self._transform = SymmetricalLogTransform(base, linthresh, linscale)
         self.base = base
         self.linthresh = linthresh
         self.linscale = linscale
diff --git a/lib/matplotlib/tests/test_scale.py b/lib/matplotlib/tests/test_scale.py
@@ -106,11 +106,20 @@ def test_logscale_mask():
     ax.set(yscale="log")
 
 
-def test_extra_kwargs_raise():
+def test_extra_kwargs_raise_or_warn():
     fig, ax = plt.subplots()
-    with pytest.raises(ValueError):
+
+    # with pytest.raises(TypeError):
+    with pytest.warns(MatplotlibDeprecationWarning):
+        ax.set_yscale('linear', nonpos='mask')
+
+    with pytest.raises(TypeError):
         ax.set_yscale('log', nonpos='mask')
 
+    # with pytest.raises(TypeError):
+    with pytest.warns(MatplotlibDeprecationWarning):
+        ax.set_yscale('symlog', nonpos='mask')
+
 
 def test_logscale_invert_transform():
     fig, ax = plt.subplots()
