BUG: ensure we never do nan < nan

mhvk · mhvk · commit 5c42d71c8bc9 · 2025-04-10T12:43:58.000-04:00
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -3756,7 +3756,7 @@ def apply_mask(arrays, mask):
                     f"'{dep_axis}err' must not contain None. "
                     "Use NaN if you want to skip a value.")
 
-            if np.any((err < -err) & (err == err)):
+            if np.any((check := err[err == err]) < -check):
                 # like err<0, but also works for timedelta and nan.
                 raise ValueError(
                     f"'{dep_axis}err' must not contain negative values")
