Merge pull request #19640 from meeseeksmachine/auto-backport-of-pr-19639-on-v3.4.x

QuLogic · web-flow · commit 84b9a8870bd5 · 2021-03-04T05:02:47.000-05:00
Backport PR #19639 on branch v3.4.x (FIX: do not allow single element list of str in subplot_mosaic)
diff --git a/lib/matplotlib/figure.py b/lib/matplotlib/figure.py
@@ -1692,6 +1692,8 @@ def _make_array(inp):
 
             """
             r0, *rest = inp
+            if isinstance(r0, str):
+                raise ValueError('List layout specification must be 2D')
             for j, r in enumerate(rest, start=1):
                 if isinstance(r, str):
                     raise ValueError('List layout specification must be 2D')
diff --git a/lib/matplotlib/tests/test_figure.py b/lib/matplotlib/tests/test_figure.py
@@ -760,6 +760,8 @@ def test_empty(self, fig_test, fig_ref, x, empty_sentinel):
     def test_fail_list_of_str(self):
         with pytest.raises(ValueError, match='must be 2D'):
             plt.subplot_mosaic(['foo', 'bar'])
+        with pytest.raises(ValueError, match='must be 2D'):
+            plt.subplot_mosaic(['foo'])
 
     @check_figures_equal(extensions=["png"])
     @pytest.mark.parametrize("subplot_kw", [{}, {"projection": "polar"}, None])
