Mar 13, 2019 · Mar 13, 2019
diff --git a/doc/api/next_api_changes/2019-03-07-AL.rst b/doc/api/next_api_changes/2019-03-07-AL.rst
 API changes
 ```````````

 Passing the ``block`` argument of ``plt.show`` positionally is deprecated; it
 should be passed by keyword.

 When using the nbagg backend, ``plt.show`` used to silently accept and ignore
 all combinations of positional and keyword arguments.  This behavior is
 deprecated.
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
                cls.trigger_manager_draw(manager)

    @classmethod
    @cbook._make_keyword_only("3.1", "block")
    def show(cls, block=None):
        """Show all figures.
        """
        Show all figures.

        `show` blocks by calling `mainloop` if *block* is ``True``, or if it
        is ``None`` and we are neither in IPython's ``%pylab`` mode, nor in
diff --git a/lib/matplotlib/backends/backend_nbagg.py b/lib/matplotlib/backends/backend_nbagg.py
    # Jupyter/IPython 3.x or earlier
    from IPython.kernel.comm import Comm

 from matplotlib import is_interactive
 from matplotlib importcbook,is_interactive
 from matplotlib._pylab_helpers import Gcf
 from matplotlib.backend_bases import (
    _Backend, FigureCanvasBase, NavigationToolbar2)
        manager.show()

    @staticmethod
    def show(*args, **kwargs):
    def show(*args, block=None, **kwargs):
        if args or kwargs:
            cbook.warn_deprecated(
                "3.1", message="Passing arguments to show(), other than "
                "passing 'block' by keyword, is deprecated %(since)s, and "
                "support for it will be removed %(removal)s.")

        ## TODO: something to do when keyword block==False ?
        from matplotlib._pylab_helpers import Gcf

diff --git a/lib/matplotlib/backends/backend_template.py b/lib/matplotlib/backends/backend_template.py
    """


 def show(block=None):
 def show(*,block=None):
    """
    For image backends - is not required.
    For GUI backends - show() is usually the last line of a pyplot script and
diff --git a/lib/matplotlib/cbook/__init__.py b/lib/matplotlib/cbook/__init__.py

 import matplotlib
 from .deprecation import (
    deprecated, warn_deprecated, _rename_parameter, _delete_parameter,
    deprecated, warn_deprecated,
    _rename_parameter, _delete_parameter, _make_keyword_only,
    _suppress_matplotlib_deprecation_warning,
    MatplotlibDeprecationWarning, mplDeprecation)

diff --git a/lib/matplotlib/cbook/deprecation.py b/lib/matplotlib/cbook/deprecation.py
    return wrapper


 def _make_keyword_only(since, name, func=None):
    """
    Decorator indicating that passing parameter *name* (or any of the following
    ones) positionally to *func* is being deprecated.

    Note that this decorator **cannot** be applied to a function that has a
    pyplot-level wrapper, as the wrapper always pass all arguments by keyword.
    If it is used, users will see spurious DeprecationWarnings every time they
    call the pyplot wrapper.
    """

    if func is None:
        return functools.partial(_make_keyword_only, since, name)

    signature = inspect.signature(func)
    POK = inspect.Parameter.POSITIONAL_OR_KEYWORD
    KWO = inspect.Parameter.KEYWORD_ONLY
    assert (name in signature.parameters
            and signature.parameters[name].kind == POK), (
        f"Matplotlib internal error: {name!r} must be a positional-or-keyword "
        f"parameter for {func.__name__}()")
    names = [*signature.parameters]
    kwonly = [name for name in names[names.index(name):]
              if signature.parameters[name].kind == POK]
    func.__signature__ = signature.replace(parameters=[
        param.replace(kind=inspect.Parameter.KEYWORD_ONLY)
        if param.name in kwonly
        else param
        for param in signature.parameters.values()])

    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        bound = signature.bind(*args, **kwargs)
        if name in bound.arguments and name not in kwargs:
            warn_deprecated(
                since, message="Passing the %(name)s %(obj_type)s "
                "positionally is deprecated since Matplotlib %(since)s; the "
                "parameter will become keyword-only %(removal)s.",
                name=name, obj_type=f"parameter of {func.__name__}()")
        return func(*args, **kwargs)

    return wrapper


 @contextlib.contextmanager
 def _suppress_matplotlib_deprecation_warning():
    with warnings.catch_warnings():
diff --git a/lib/matplotlib/tests/test_cbook.py b/lib/matplotlib/tests/test_cbook.py

 import matplotlib.cbook as cbook
 import matplotlib.colors as mcolors
 from matplotlib.cbook import delete_masked_points as dmp
 from matplotlib.cbook import (
    MatplotlibDeprecationWarning, delete_masked_points as dmp)


 def test_is_hashable():
    s = pd.Series(range(5), index=range(10, 15))
    actual = cbook.safe_first_element(s)
    assert actual == 0


 def test_make_keyword_only(recwarn):
    @cbook._make_keyword_only("3.0", "arg")
    def func(pre, arg, post=None):
        pass

    func(1, arg=2)
    assert len(recwarn) == 0

    with pytest.warns(MatplotlibDeprecationWarning):
        func(1, 2)
    with pytest.warns(MatplotlibDeprecationWarning):
        func(1, 2, 3)
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,9 @@
		API changes
		```````````

		Passing the ``block`` argument of ``plt.show`` positionally is deprecated; it
		should be passed by keyword.

		When using the nbagg backend, ``plt.show`` used to silently accept and ignore
		all combinations of positional and keyword arguments. This behavior is
		deprecated.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -3217,8 +3217,10 @@ def draw_if_interactive(cls):
		cls.trigger_manager_draw(manager)

		@classmethod
		@cbook._make_keyword_only("3.1", "block")
		def show(cls, block=None):
		"""Show all figures.
		"""
		Show all figures.

		`show` blocks by calling `mainloop` if block is ``True``, or if it
		is ``None`` and we are neither in IPython's ``%pylab`` mode, nor in
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -17,7 +17,7 @@
		# Jupyter/IPython 3.x or earlier
		from IPython.kernel.comm import Comm

		from matplotlib import is_interactive
		from matplotlib importcbook,is_interactive
		from matplotlib._pylab_helpers import Gcf
		from matplotlib.backend_bases import (
		_Backend, FigureCanvasBase, NavigationToolbar2)
Expand DownExpand Up		@@ -241,7 +241,13 @@ def trigger_manager_draw(manager):
		manager.show()

		@staticmethod
		def show(args, *kwargs):
		def show(args, block=None, *kwargs):
		if args or kwargs:
		cbook.warn_deprecated(
		"3.1", message="Passing arguments to show(), other than "
		"passing 'block' by keyword, is deprecated %(since)s, and "
		"support for it will be removed %(removal)s.")

		## TODO: something to do when keyword block==False ?
		from matplotlib._pylab_helpers import Gcf

Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -173,7 +173,7 @@ def draw_if_interactive():
		"""


		def show(block=None):
		def show(*,block=None):
		"""
		For image backends - is not required.
		For GUI backends - show() is usually the last line of a pyplot script and
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -32,7 +32,8 @@

		import matplotlib
		from .deprecation import (
		deprecated, warn_deprecated, _rename_parameter, _delete_parameter,
		deprecated, warn_deprecated,
		_rename_parameter, _delete_parameter, _make_keyword_only,
		_suppress_matplotlib_deprecation_warning,
		MatplotlibDeprecationWarning, mplDeprecation)

Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -371,6 +371,50 @@ def wrapper(args, *kwargs):
		return wrapper


		def _make_keyword_only(since, name, func=None):
		"""
		Decorator indicating that passing parameter name (or any of the following
		ones) positionally to func is being deprecated.

		Note that this decorator cannot be applied to a function that has a
		pyplot-level wrapper, as the wrapper always pass all arguments by keyword.
		If it is used, users will see spurious DeprecationWarnings every time they
		call the pyplot wrapper.
		"""

		if func is None:
		return functools.partial(_make_keyword_only, since, name)

		signature = inspect.signature(func)
		POK = inspect.Parameter.POSITIONAL_OR_KEYWORD
		KWO = inspect.Parameter.KEYWORD_ONLY
		assert (name in signature.parameters
		and signature.parameters[name].kind == POK), (
		f"Matplotlib internal error: {name!r} must be a positional-or-keyword "
		f"parameter for {func.__name__}()")
		names = [*signature.parameters]
		kwonly = [name for name in names[names.index(name):]
		if signature.parameters[name].kind == POK]
		func.__signature__ = signature.replace(parameters=[
		param.replace(kind=inspect.Parameter.KEYWORD_ONLY)
		if param.name in kwonly
		else param
		for param in signature.parameters.values()])

		@functools.wraps(func)
		def wrapper(args, *kwargs):
		bound = signature.bind(args, *kwargs)
		if name in bound.arguments and name not in kwargs:
		warn_deprecated(
		since, message="Passing the %(name)s %(obj_type)s "
		"positionally is deprecated since Matplotlib %(since)s; the "
		"parameter will become keyword-only %(removal)s.",
		name=name, obj_type=f"parameter of {func.__name__}()")
		return func(args, *kwargs)

		return wrapper


		@contextlib.contextmanager
		def _suppress_matplotlib_deprecation_warning():
		with warnings.catch_warnings():
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -13,7 +13,8 @@

		import matplotlib.cbook as cbook
		import matplotlib.colors as mcolors
		from matplotlib.cbook import delete_masked_points as dmp
		from matplotlib.cbook import (
		MatplotlibDeprecationWarning, delete_masked_points as dmp)


		def test_is_hashable():
Expand DownExpand Up		@@ -545,3 +546,17 @@ def test_safe_first_element_pandas_series(pd):
		s = pd.Series(range(5), index=range(10, 15))
		actual = cbook.safe_first_element(s)
		assert actual == 0


		def test_make_keyword_only(recwarn):
		@cbook._make_keyword_only("3.0", "arg")
		def func(pre, arg, post=None):
		pass

		func(1, arg=2)
		assert len(recwarn) == 0

		with pytest.warns(MatplotlibDeprecationWarning):
		func(1, 2)
		with pytest.warns(MatplotlibDeprecationWarning):
		func(1, 2, 3)