add validator for timedelta

Author: Kislovskiy

lib/matplotlib/axes/_axes.py

@@ -3,6 +3,7 @@
 import logging
 import math
 from numbers import Integral, Number
+from datetime import timedelta
 
 import numpy as np
 from numpy import ma
@@ -3289,8 +3290,8 @@ def has_negative_values(array):
                 return False
             try:
                 return np.any(array < 0)
-            except TypeError:
-                pass   # Don't fail on 'datetime.*' types
+            except TypeError:  # if array contains 'datetime.timedelta' types
+                return np.any(array < timedelta(0))
 
         if has_negative_values(xerr) or has_negative_values(yerr):
             raise ValueError(

lib/matplotlib/tests/test_axes.py

@@ -3524,6 +3524,12 @@ def test_xerr_yerr_positive():
         ax.errorbar(x=[0], y=[0], xerr=[[-0.5], [1]])
     with pytest.raises(ValueError, match=error_message):
         ax.errorbar(x=[0], y=[0], yerr=[[-0.5], [1]])
+    with pytest.raises(ValueError, match=error_message):
+        x = np.arange(5)
+        y = [datetime.datetime(2021, 9, i * 2 + 1) for i in x]
+        ax.errorbar(x=x,
+                    y=y,
+                    yerr=datetime.timedelta(days=-10))
 
 
 @check_figures_equal()