Check that xerr/yerr values are not None in errorbar

oscargus · oscargus · commit ab67ee18426a · 2023-12-01T10:20:54.000+01:00
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -3682,6 +3682,11 @@ def apply_mask(arrays, mask):
                     f"'{dep_axis}err' (shape: {np.shape(err)}) must be a "
                     f"scalar or a 1D or (2, n) array-like whose shape matches "
                     f"'{dep_axis}' (shape: {np.shape(dep)})") from None
+            if err.dtype is np.dtype(object) and np.any(err == None):  # noqa: E711
+                raise ValueError(
+                    f"'{dep_axis}err' must not contain None. "
+                    "Use NaN if you want to skip a value.")
+
             res = np.zeros(err.shape, dtype=bool)  # Default in case of nan
             if np.any(np.less(err, -err, out=res, where=(err == err))):
                 # like err<0, but also works for timedelta and nan.
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -4127,6 +4127,20 @@ def test_xerr_yerr_not_negative():
                     yerr=datetime.timedelta(days=-10))
 
 
+def test_xerr_yerr_not_none():
+    ax = plt.figure().subplots()
+
+    with pytest.raises(ValueError,
+                       match="'xerr' must not contain None"):
+        ax.errorbar(x=[0], y=[0], xerr=[[None], [1]], yerr=[[None], [1]])
+    with pytest.raises(ValueError,
+                       match="'xerr' must not contain None"):
+        ax.errorbar(x=[0], y=[0], xerr=[[None], [1]])
+    with pytest.raises(ValueError,
+                       match="'yerr' must not contain None"):
+        ax.errorbar(x=[0], y=[0], yerr=[[None], [1]])
+
+
 @check_figures_equal()
 def test_errorbar_every(fig_test, fig_ref):
     x = np.linspace(0, 1, 15)
