matplotlib · tacaswell · Jan 28, 2019 · Jan 7, 2019 · Jan 7, 2019 · Jan 8, 2019
diff --git a/doc/api/next_api_changes/2018-01-10-AL.rst b/doc/api/next_api_changes/2018-01-10-AL.rst
@@ -0,0 +1,11 @@
+Changes in parameter names
+``````````````````````````
+
+- The ``arg`` parameter to `matplotlib.use` has been renamed to ``backend``.
+- The ``normed`` parameter to `Axes.hist2d` has been renamed to ``density``.
+- The ``s`` parameter to `Annotation` (and indirectly `Axes.annotation`) has
+  been renamed to ``text``.
+
+In each case, the old parameter name remains supported (it cannot be used
+simultaneously with the new name), but suppport for it will be dropped in
+Matplotlib 3.3.
diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
@@ -1183,13 +1183,14 @@ def __exit__(self, exc_type, exc_value, exc_tb):
         self.__fallback()
 
 
-def use(arg, warn=False, force=True):
+@cbook._rename_parameter("3.1", "arg", "backend")
+def use(backend, warn=False, force=True):
     """
     Set the matplotlib backend to one of the known backends.
 
     Parameters
     ----------
-    arg : str
+    backend : str
         The backend to switch to.  This can either be one of the
         'standard' backend names:
 
@@ -1205,6 +1206,8 @@ def use(arg, warn=False, force=True):
 
         Note: Standard backend names are case-insensitive here.
 
+        *arg* is a deprecated synonym for this parameter.
+
     warn : bool, optional
         If True, warn if this is called after pyplot has been imported
         and a backend is set up.
@@ -1221,7 +1224,7 @@ def use(arg, warn=False, force=True):
     :ref:`backends`
     matplotlib.get_backend
     """
-    name = validate_backend(arg)
+    name = validate_backend(backend)
 
     # if setting back to the same thing, do nothing
     if (dict.__getitem__(rcParams, 'backend') == name):

diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -6845,7 +6845,8 @@ def hist(self, x, bins=None, range=None, density=None, weights=None,
             return tops, bins, cbook.silent_list('Lists of Patches', patches)
 
     @_preprocess_data(replace_names=["x", "y", "weights"])
-    def hist2d(self, x, y, bins=10, range=None, normed=False, weights=None,
+    @cbook._rename_parameter("3.1", "normed", "density")
+    def hist2d(self, x, y, bins=10, range=None, density=False, weights=None,
                cmin=None, cmax=None, **kwargs):
         """
         Make a 2D histogram plot.
@@ -6879,8 +6880,9 @@ def hist2d(self, x, y, bins=10, range=None, normed=False, weights=None,
              xmax], [ymin, ymax]]``. All values outside of this range will be
              considered outliers and not tallied in the histogram.
 
-        normed : bool, optional, default: False
-             Normalize histogram.
+        density : bool, optional, default: False
+             Normalize histogram.  *normed* is a deprecated synonym for this
+             parameter.
 
         weights : array_like, shape (n, ), optional, default: None
             An array of values w_i weighing each sample (x_i, y_i).
@@ -6939,7 +6941,7 @@ def hist2d(self, x, y, bins=10, range=None, normed=False, weights=None,
         """
 
         h, xedges, yedges = np.histogram2d(x, y, bins=bins, range=range,
-                                           normed=normed, weights=weights)
+                                           normed=density, weights=weights)
 
         if cmin is not None:
             h[h < cmin] = None

diff --git a/lib/matplotlib/cbook/__init__.py b/lib/matplotlib/cbook/__init__.py
@@ -32,7 +32,8 @@
 
 import matplotlib
 from .deprecation import (
-    mplDeprecation, deprecated, warn_deprecated, MatplotlibDeprecationWarning)
+    deprecated, warn_deprecated, _rename_parameter,
+    MatplotlibDeprecationWarning, mplDeprecation)
 
 
 @deprecated("3.0")

diff --git a/lib/matplotlib/cbook/deprecation.py b/lib/matplotlib/cbook/deprecation.py
@@ -258,3 +258,51 @@ def wrapper(*args, **kwargs):
         return finalize(wrapper, new_doc)
 
     return deprecate
+
+
+def _rename_parameter(since, old, new, func=None):
+    """
+    Decorator indicating that parameter *old* of *func* is renamed to *new*.
+
+    The actual implementation of *func* should use *new*, not *old*.  If *old*
+    is passed to *func*, a DeprecationWarning is emitted, and its value is
+    used, even if *new* is also passed by keyword (this is to simplify pyplot
+    wrapper functions, which always pass *new* explicitly to the Axes method).
+    If *new* is also passed but positionally, a TypeError will be raised by the
+    underlying function during argument binding.
+
+    Examples
+    --------
+
+    ::
+        @_rename_parameter("3.1", "bad_name", "good_name")
+        def func(good_name): ...
+    """
+
+    if func is None:
+        return functools.partial(_rename_parameter, since, old, new)
+
+    signature = inspect.signature(func)
+    assert old not in signature.parameters, (
+        f"Matplotlib internal error: {old!r} cannot be a parameter for "
+        f"{func.__name__}()")
+    assert new in signature.parameters, (
+        f"Matplotlib internal error: {new!r} must be a parameter for "
+        f"{func.__name__}()")
+
+    @functools.wraps(func)
+    def wrapper(*args, **kwargs):
+        if old in kwargs:
+            warn_deprecated(
+                since, message=f"The {old!r} parameter of {func.__name__}() "
+                f"has been renamed {new!r} since Matplotlib {since}; support "
+                f"for the old name will be dropped %(removal)s.")
+            kwargs[new] = kwargs.pop(old)
+        return func(*args, **kwargs)
+
+    # wrapper() must keep the same documented signature as func(): if we
+    # instead made both *old* and *new* appear in wrapper()'s signature, they
+    # would both show up in the pyplot function for an Axes method as well and
+    # pyplot would explicitly pass both arguments to the Axes method.
+
+    return wrapper
diff --git a/lib/matplotlib/pyplot.py b/lib/matplotlib/pyplot.py
@@ -2632,12 +2632,12 @@ def hist(
 # Autogenerated by boilerplate.py.  Do not edit as changes will be lost.
 @_autogen_docstring(Axes.hist2d)
 def hist2d(
-        x, y, bins=10, range=None, normed=False, weights=None,
+        x, y, bins=10, range=None, density=False, weights=None,
         cmin=None, cmax=None, *, data=None, **kwargs):
     __ret = gca().hist2d(
-        x, y, bins=bins, range=range, normed=normed, weights=weights,
-        cmin=cmin, cmax=cmax, **({"data": data} if data is not None
-        else {}), **kwargs)
+        x, y, bins=bins, range=range, density=density,
+        weights=weights, cmin=cmin, cmax=cmax, **({"data": data} if
+        data is not None else {}), **kwargs)
     sci(__ret[-1])
     return __ret
 

diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -1739,6 +1739,17 @@ def test_hist2d_transpose():
     ax.hist2d(x, y, bins=10, rasterized=True)
 
 
+def test_hist2d_density_normed():
+    x, y = np.random.random((2, 100))
+    ax = plt.figure().subplots()
+    for obj in [ax, plt]:
+        obj.hist2d(x, y, density=True)
+        with pytest.warns(MatplotlibDeprecationWarning):
+            obj.hist2d(x, y, normed=True)
+        with pytest.warns(MatplotlibDeprecationWarning):
+            obj.hist2d(x, y, density=True, normed=True)
+
+
 class TestScatter(object):
     @image_comparison(baseline_images=['scatter'],
                       style='mpl20', remove_text=True)

diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
@@ -1971,15 +1971,16 @@ class Annotation(Text, _AnnotationBase):
     def __str__(self):
         return "Annotation(%g, %g, %r)" % (self.xy[0], self.xy[1], self._text)
 
-    def __init__(self, s, xy,
+    @cbook._rename_parameter("3.1", "s", "text")
+    def __init__(self, text, xy,
                  xytext=None,
                  xycoords='data',
                  textcoords=None,
                  arrowprops=None,
                  annotation_clip=None,
                  **kwargs):
         """
-        Annotate the point *xy* with text *s*.
+        Annotate the point *xy* with text *text*.
 
         In the simplest form, the text is placed at *xy*.
 
@@ -1989,8 +1990,9 @@ def __init__(self, s, xy,
 
         Parameters
         ----------
-        s : str
-            The text of the annotation.
+        text : str
+            The text of the annotation.  *s* is a deprecated synonym for this
+            parameter.
 
         xy : (float, float)
             The point *(x,y)* to annotate.
@@ -2165,7 +2167,7 @@ def transform(renderer) -> Transform
             xytext = self.xy
         x, y = xytext
 
-        Text.__init__(self, x, y, s, **kwargs)
+        Text.__init__(self, x, y, text, **kwargs)
 
         self.arrowprops = arrowprops