Nov 16, 2025 · Nov 16, 2025 · Nov 16, 2025 · Nov 29, 2025
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
 import itertools
 import logging
 import math
 import datetime
 from numbers import Integral, Number, Real

 import re
        elif len(widths) != N:
            raise ValueError(datashape_message.format("widths"))

        # For usability / better error message:
        # Validate that datetime-like positions have timedelta-like widths.
        # Checking only the first element is good enough for standard misuse cases
        pos0 = positions[0]
        width0 = widths if np.isscalar(widths) else widths[0]
        if (isinstance(pos0, (datetime.datetime, datetime.date))
                and not isinstance(width0, datetime.timedelta)):
            raise TypeError(
                "datetime/date 'position' values, require timedelta 'widths'")
        elif (isinstance(pos0, np.datetime64)
                and not isinstance(width0, np.timedelta64)):
            raise TypeError(
                "np.datetime64 'position' values, require np.timedelta64 'widths'")
        # Validate side
        _api.check_in_list(["both", "low", "high"], side=side)

diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
                      showextrema=True, showmedians=True, side=side)


 def violin_plot_stats():
    datetimes = [
        datetime.datetime(2023, 2, 10),
        datetime.datetime(2023, 5, 18),
        datetime.datetime(2023, 6, 6)
    ]
    return [{
        'coords': datetimes,
        'vals': [1.2, 2.8, 1.5, 3.1, 2.0, 1.8, 2.5],
        'mean': 2.1285714285714286,
        'median': 2.0,
        'min': 1.2,
        'max': 3.1,
        'quantiles': [1.5, 2.0, 2.5]
    }, {
        'coords': datetimes,
        'vals': [0.8, 1.1, 0.9, 1.4, 1.0, 1.3, 1.2],
        'mean': 1.1,
        'median': 1.1,
        'min': 0.8,
        'max': 1.4,
        'quantiles': [0.95, 1.1, 1.25]
    }]


 def test_datetime_positions_with_datetime64():
    """Test that datetime positions with float widths raise TypeError."""
    fig, ax = plt.subplots()
    positions = [np.datetime64('2020-01-01'), np.datetime64('2021-01-01')]
    widths = [0.5, 1.0]
    with pytest.raises(TypeError,
    match="np.datetime64 'position' values, require np.timedelta64 'widths'"):
        ax.violin(violin_plot_stats(), positions=positions, widths=widths)


 def test_datetime_positions_with_float_widths_raises():
    """Test that datetime positions with float widths raise TypeError."""
    fig, ax = plt.subplots()
    positions = [datetime.datetime(2020, 1, 1), datetime.datetime(2021, 1, 1)]
    widths = [0.5, 1.0]
    with pytest.raises(TypeError,
    match="datetime/date 'position' values, require timedelta 'widths'"):
        ax.violin(violin_plot_stats(), positions=positions, widths=widths)


 def test_datetime_positions_with_scalar_float_width_raises():
    """Test that datetime positions with scalar float width raise TypeError."""
    fig, ax = plt.subplots()
    positions = [datetime.datetime(2020, 1, 1), datetime.datetime(2021, 1, 1)]
    widths = 0.75
    with pytest.raises(TypeError,
    match="datetime/date 'position' values, require timedelta 'widths'"):
        ax.violin(violin_plot_stats(), positions=positions, widths=widths)


 def test_numeric_positions_with_float_widths_ok():
    """Test that numeric positions with float widths work."""
    fig, ax = plt.subplots()
    positions = [1.0, 2.0]
    widths = [0.5, 1.0]
    ax.violin(violin_plot_stats(), positions=positions, widths=widths)


 def test_mixed_positions_datetime_and_numeric_behaves():
    """Test that mixed datetime and numeric positions
    with float widths raise TypeError.
    """
    fig, ax = plt.subplots()
    positions = [datetime.datetime(2020, 1, 1), 2.0]
    widths = [0.5, 1.0]
    with pytest.raises(TypeError,
    match="datetime/date 'position' values, require timedelta 'widths'"):
        ax.violin(violin_plot_stats(), positions=positions, widths=widths)


 def test_violinplot_bad_positions():
    ax = plt.axes()
    # First 9 digits of frac(sqrt(47))
Original file line number	Diff line number	Diff line change
Expand Up		@@ -2,6 +2,7 @@
		import itertools
		import logging
		import math
		import datetime
		from numbers import Integral, Number, Real

		import re
Expand DownExpand Up		@@ -9057,6 +9058,19 @@ def violin(self, vpstats, positions=None, vert=None,
		elif len(widths) != N:
		raise ValueError(datashape_message.format("widths"))

		# For usability / better error message:
		# Validate that datetime-like positions have timedelta-like widths.
		# Checking only the first element is good enough for standard misuse cases
		pos0 = positions[0]
		width0 = widths if np.isscalar(widths) else widths[0]
		if (isinstance(pos0, (datetime.datetime, datetime.date))
		and not isinstance(width0, datetime.timedelta)):
		raise TypeError(
		"datetime/date 'position' values, require timedelta 'widths'")
		elif (isinstance(pos0, np.datetime64)
		and not isinstance(width0, np.timedelta64)):
		raise TypeError(
		"np.datetime64 'position' values, require np.timedelta64 'widths'")
		# Validate side
		_api.check_in_list(["both", "low", "high"], side=side)

Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -4121,6 +4121,81 @@ def test_violinplot_sides():
		showextrema=True, showmedians=True, side=side)


		def violin_plot_stats():
		datetimes = [
		datetime.datetime(2023, 2, 10),
		datetime.datetime(2023, 5, 18),
		datetime.datetime(2023, 6, 6)
		]
		return [{
		'coords': datetimes,
		'vals': [1.2, 2.8, 1.5, 3.1, 2.0, 1.8, 2.5],
		'mean': 2.1285714285714286,
		'median': 2.0,
		'min': 1.2,
		'max': 3.1,
		'quantiles': [1.5, 2.0, 2.5]
		}, {
		'coords': datetimes,
		'vals': [0.8, 1.1, 0.9, 1.4, 1.0, 1.3, 1.2],
		'mean': 1.1,
		'median': 1.1,
		'min': 0.8,
		'max': 1.4,
		'quantiles': [0.95, 1.1, 1.25]
		}]


		def test_datetime_positions_with_datetime64():
		"""Test that datetime positions with float widths raise TypeError."""
		fig, ax = plt.subplots()
		positions = [np.datetime64('2020-01-01'), np.datetime64('2021-01-01')]
		widths = [0.5, 1.0]
		with pytest.raises(TypeError,
		match="np.datetime64 'position' values, require np.timedelta64 'widths'"):
		ax.violin(violin_plot_stats(), positions=positions, widths=widths)


		def test_datetime_positions_with_float_widths_raises():
		"""Test that datetime positions with float widths raise TypeError."""
		fig, ax = plt.subplots()
		positions = [datetime.datetime(2020, 1, 1), datetime.datetime(2021, 1, 1)]
		widths = [0.5, 1.0]
		with pytest.raises(TypeError,
		match="datetime/date 'position' values, require timedelta 'widths'"):
		ax.violin(violin_plot_stats(), positions=positions, widths=widths)


		def test_datetime_positions_with_scalar_float_width_raises():
		"""Test that datetime positions with scalar float width raise TypeError."""
		fig, ax = plt.subplots()
		positions = [datetime.datetime(2020, 1, 1), datetime.datetime(2021, 1, 1)]
		widths = 0.75
		with pytest.raises(TypeError,
		match="datetime/date 'position' values, require timedelta 'widths'"):
		ax.violin(violin_plot_stats(), positions=positions, widths=widths)


		def test_numeric_positions_with_float_widths_ok():
		"""Test that numeric positions with float widths work."""
		fig, ax = plt.subplots()
		positions = [1.0, 2.0]
		widths = [0.5, 1.0]
		ax.violin(violin_plot_stats(), positions=positions, widths=widths)


		def test_mixed_positions_datetime_and_numeric_behaves():
		"""Test that mixed datetime and numeric positions
		with float widths raise TypeError.
		"""
		fig, ax = plt.subplots()
		positions = [datetime.datetime(2020, 1, 1), 2.0]
		widths = [0.5, 1.0]
		with pytest.raises(TypeError,
		match="datetime/date 'position' values, require timedelta 'widths'"):
		ax.violin(violin_plot_stats(), positions=positions, widths=widths)


		def test_violinplot_bad_positions():
		ax = plt.axes()
		# First 9 digits of frac(sqrt(47))
Expand Down