Jun 4, 2025 · Jun 4, 2025 · Jun 4, 2025 · Jun 4, 2025 · Jun 4, 2025
diff --git a/lib/matplotlib/collections.py b/lib/matplotlib/collections.py

    def get_paths(self):
        return self._paths

    def check_consistency(self):
        """
        Emit warnings if the lengths of certain properties do not match
        the number of paths.

        This method checks whether the lengths of `sizes` and `edgecolors`
        are either 1 or equal to the number of paths in the collection.
        If not, a warning is issued.

        This is useful for identifying potential bugs or silent mismatches
        in collection properties when plotting, especially when properties
        are expected to be applied per-path.

        Notes
        -----
        - This method does not raise an error, only a warning.
        - It is recommended to call this at draw-time to ensure properties
        have been fully set.

        Warnings
        --------
        UserWarning
            If the number of sizes or edgecolors does not match the number
            of paths and is not a singleton (length 1).

        Examples
        --------
        >>> paths = [Path(...), Path(...), Path(...)]
        >>> pc = PathCollection(paths, sizes=[10, 20])  # 3 paths, 2 sizes
        >>> pc.check_consistency()
        UserWarning: Number of sizes does not match number of paths.
        """
        n_paths = len(self.get_paths())
        if self._sizes is not None and len(self._sizes) not in (1, n_paths):
            warnings.warn("Number of sizes does not match number of paths.")
        if self._edgecolors is not None and len(self._edgecolors) not in (1, n_paths):
            warnings.warn("Number of edgecolors does not match number of paths.")


    def legend_elements(self, prop="colors", num="auto",
                        fmt=None, func=lambda x: x, **kwargs):
            labels.append(l)

        return handles, labels

    def draw(self, renderer):
        """
        Draw the collection using the given renderer.

        This override adds consistency checks before delegating
        to the base implementation.

        Parameters
        ----------
        renderer : RendererBase instance
        The renderer to use for drawing.
        """
        self.check_consistency()
        return super().draw(renderer)


 class PolyCollection(_CollectionWithSizes):
diff --git a/lib/matplotlib/tests/test_collections.py b/lib/matplotlib/tests/test_collections.py
 import matplotlib.path as mpath
 import matplotlib.transforms as mtransforms
 from matplotlib.collections import (Collection, LineCollection,
                                    EventCollection, PolyCollection)
                                    EventCollection, PolyCollection, PathCollection)
 from matplotlib.collections import FillBetweenPolyCollection
 from matplotlib.testing.decorators import check_figures_equal, image_comparison

 from matplotlib.path import Path

 @pytest.fixture(params=["pcolormesh", "pcolor"])
 def pcfunc(request):
    return request.param

    ax.add_collection(coll)

    plt.draw()

 def test_pathcollection_size_mismatch_warning():

    paths = [Path([(0, 0), (1, 0), (0.5, 1)]) for _ in range(5)]
    fig, ax = plt.subplots()
    with pytest.warns(UserWarning, match="Number of sizes does not match"):
        pc = PathCollection(paths, sizes=[10, 20])
        ax.add_collection(pc)
        fig.canvas.draw()
Original file line number	Diff line number	Diff line change
Expand Up		@@ -16,12 +16,12 @@
		import matplotlib.path as mpath
		import matplotlib.transforms as mtransforms
		from matplotlib.collections import (Collection, LineCollection,
		EventCollection, PolyCollection)
		EventCollection, PolyCollection, PathCollection)
		from matplotlib.collections import FillBetweenPolyCollection
		from matplotlib.testing.decorators import check_figures_equal, image_comparison

		from matplotlib.path import Path

		@pytest.fixture(params=["pcolormesh", "pcolor"])
Check failure on line 24 in lib/matplotlib/tests/test_collections.py View workflow job for this annotation GitHub Actions/ ruff `[rdjson] reported by reviewdog 🐶Expected 2 blank lines, found 1Raw Output:message:"Expected 2 blank lines, found 1" location:{path:"/home/runner/work/matplotlib/matplotlib/lib/matplotlib/tests/test_collections.py" range:{start:{line:24 column:1} end:{line:24 column:2}}} source:{name:"ruff" url:"https://docs.astral.sh/ruff"} code:{value:"E302" url:"https://docs.astral.sh/ruff/rules/blank-lines-top-level"} suggestions:{range:{start:{line:23 column:1} end:{line:24 column:1}} text:"\n\n"}`
		def pcfunc(request):
		return request.param

Expand DownExpand Up		@@ -1533,3 +1533,12 @@
		ax.add_collection(coll)

		plt.draw()

		def test_pathcollection_size_mismatch_warning():
Check failure on line 1537 in lib/matplotlib/tests/test_collections.py View workflow job for this annotation GitHub Actions/ ruff `[rdjson] reported by reviewdog 🐶Expected 2 blank lines, found 1Raw Output:message:"Expected 2 blank lines, found 1" location:{path:"/home/runner/work/matplotlib/matplotlib/lib/matplotlib/tests/test_collections.py" range:{start:{line:1537 column:1} end:{line:1537 column:4}}} source:{name:"ruff" url:"https://docs.astral.sh/ruff"} code:{value:"E302" url:"https://docs.astral.sh/ruff/rules/blank-lines-top-level"} suggestions:{range:{start:{line:1536 column:1} end:{line:1537 column:1}} text:"\n\n"}`

		paths = [Path([(0, 0), (1, 0), (0.5, 1)]) for _ in range(5)]
		fig, ax = plt.subplots()
		with pytest.warns(UserWarning, match="Number of sizes does not match"):
		pc = PathCollection(paths, sizes=[10, 20])
		ax.add_collection(pc)
		fig.canvas.draw()
Check failure on line 1544 in lib/matplotlib/tests/test_collections.py View workflow job for this annotation GitHub Actions/ ruff `[rdjson] reported by reviewdog 🐶Trailing whitespaceRaw Output:message:"Trailing whitespace" location:{path:"/home/runner/work/matplotlib/matplotlib/lib/matplotlib/tests/test_collections.py" range:{start:{line:1544 column:26} end:{line:1544 column:28}}} source:{name:"ruff" url:"https://docs.astral.sh/ruff"} code:{value:"W291" url:"https://docs.astral.sh/ruff/rules/trailing-whitespace"} suggestions:{range:{start:{line:1544 column:26} end:{line:1544 column:28}}}`