Allow numpy arrays to be used as elinewidth

Author: dstansby

lib/matplotlib/axes/_axes.py

@@ -3374,7 +3374,7 @@ def errorbar(self, x, y, yerr=None, xerr=None,
         # Make the style dict for the line collections (the bars).
         eb_lines_style = {**base_style, 'color': ecolor}
 
-        if elinewidth:
+        if elinewidth is not None:
             eb_lines_style['linewidth'] = elinewidth
         elif 'linewidth' in kwargs:
             eb_lines_style['linewidth'] = kwargs['linewidth']

lib/matplotlib/tests/test_axes.py

@@ -3542,6 +3542,13 @@ def test_errorbar_every(fig_test, fig_ref):
                     capsize=4, c='C1', fmt='none')
 
 
+@pytest.mark.parametrize('elinewidth', [[1, 2, 3],
+                                        np.array([1, 2, 3]),
+                                        1])
+def test_errorbar_linewidth_type(elinewidth):
+    plt.errorbar([1, 2, 3], [1, 2, 3], yerr=[1, 2, 3], elinewidth=elinewidth)
+
+
 @image_comparison(['hist_stacked_stepfilled', 'hist_stacked_stepfilled'])
 def test_hist_stacked_stepfilled():
     # make some data