Jun 11, 2019 · Feb 27, 2019
diff --git a/doc/users/next_whats_new/2019-02-27-AL.rst b/doc/users/next_whats_new/2019-02-27-AL.rst
 Unit converters now handle instances of subclasses
 ``````````````````````````````````````````````````

 Unit converters now also handle instances of subclasses of the class they have
 been registered for.
diff --git a/lib/matplotlib/tests/test_units.py b/lib/matplotlib/tests/test_units.py
 from datetime import datetime
 import platform
 from unittest.mock import MagicMock

 import matplotlib.pyplot as plt
 from matplotlib.testing.decorators import image_comparison
 from matplotlib.testing.decorators importcheck_figures_equal,image_comparison
 import matplotlib.units as munits
 import numpy as np
 import platform
 import pytest


 @image_comparison(['jpl_bar_units.png'],
                  savefig_kwarg={'dpi': 120}, style='mpl20')
 def test_jpl_bar_units():
    from datetime import datetime
    import matplotlib.testing.jpl_units as units
    units.register()

 @image_comparison(['jpl_barh_units.png'],
                  savefig_kwarg={'dpi': 120}, style='mpl20')
 def test_jpl_barh_units():
    from datetime import datetime
    import matplotlib.testing.jpl_units as units
    units.register()

    fig, ax = plt.subplots()
    ax.scatter(times, y)
    fig.canvas.draw()


 @check_figures_equal(extensions=["png"])
 def test_subclass(fig_test, fig_ref):
    class subdate(datetime):
        pass

    fig_test.subplots().plot(subdate(2000, 1, 1), 0, "o")
    fig_ref.subplots().plot(datetime(2000, 1, 1), 0, "o")
diff --git a/lib/matplotlib/units.py b/lib/matplotlib/units.py
            # If there are no elements in x, infer the units from its dtype
            if not x.size:
                return self.get_converter(np.array([0], dtype=x.dtype))
        try:  # Look up in the cache.
            return self[type(x)]
        except KeyError:
            try:  # If cache lookup fails, look up based on first element...
                first = cbook.safe_first_element(x)
            except (TypeError, StopIteration):
        for cls in type(x).__mro__:  # Look up in the cache.
            try:
                return self[cls]
            except KeyError:
                pass
            else:
                # ... and avoid infinite recursion for pathological iterables
                # where indexing returns instances of the same iterable class.
                if type(first) is not type(x):
                    return self.get_converter(first)
        try:  # If cache lookup fails, look up based on first element...
            first = cbook.safe_first_element(x)
        except (TypeError, StopIteration):
            pass
        else:
            # ... and avoid infinite recursion for pathological iterables for
            # which indexing returns instances of the same iterable class.
            if type(first) is not type(x):
                return self.get_converter(first)
        return None
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,5 @@
		Unit converters now handle instances of subclasses
		``````````````````````````````````````````````````

		Unit converters now also handle instances of subclasses of the class they have
		been registered for.
Original file line number	Diff line number	Diff line change
		@@ -1,10 +1,11 @@
		from datetime import datetime
		import platform
		from unittest.mock import MagicMock

		import matplotlib.pyplot as plt
		from matplotlib.testing.decorators import image_comparison
		from matplotlib.testing.decorators importcheck_figures_equal,image_comparison
		import matplotlib.units as munits
		import numpy as np
		import platform
		import pytest


Expand DownExpand Up		@@ -119,7 +120,6 @@ def test_empty_set_limits_with_units(quantity_converter):
		@image_comparison(['jpl_bar_units.png'],
		savefig_kwarg={'dpi': 120}, style='mpl20')
		def test_jpl_bar_units():
		from datetime import datetime
		import matplotlib.testing.jpl_units as units
		units.register()

Expand All		@@ -136,7 +136,6 @@ def test_jpl_bar_units():
		@image_comparison(['jpl_barh_units.png'],
		savefig_kwarg={'dpi': 120}, style='mpl20')
		def test_jpl_barh_units():
		from datetime import datetime
		import matplotlib.testing.jpl_units as units
		units.register()

Expand DownExpand Up		@@ -164,3 +163,12 @@ def test_scatter_element0_masked():
		fig, ax = plt.subplots()
		ax.scatter(times, y)
		fig.canvas.draw()


		@check_figures_equal(extensions=["png"])
		def test_subclass(fig_test, fig_ref):
		class subdate(datetime):
		pass

		fig_test.subplots().plot(subdate(2000, 1, 1), 0, "o")
		fig_ref.subplots().plot(datetime(2000, 1, 1), 0, "o")
Original file line number	Diff line number	Diff line change
Expand Up		@@ -205,18 +205,20 @@ def get_converter(self, x):
		# If there are no elements in x, infer the units from its dtype
		if not x.size:
		return self.get_converter(np.array([0], dtype=x.dtype))
		try: # Look up in the cache.
		return self[type(x)]
		except KeyError:
		try: # If cache lookup fails, look up based on first element...
		first = cbook.safe_first_element(x)
		except (TypeError, StopIteration):
		for cls in type(x).__mro__: # Look up in the cache.
		try:
		return self[cls]
		except KeyError:
		pass
		else:
		# ... and avoid infinite recursion for pathological iterables
		# where indexing returns instances of the same iterable class.
		if type(first) is not type(x):
		return self.get_converter(first)
		try: # If cache lookup fails, look up based on first element...
		first = cbook.safe_first_element(x)
		except (TypeError, StopIteration):
		pass
		else:
		# ... and avoid infinite recursion for pathological iterables for
		# which indexing returns instances of the same iterable class.
		if type(first) is not type(x):
		return self.get_converter(first)
		return None


Expand Down