Check for positive number or rows and cols

timhoffm · timhoffm · commit 671750cca648 · 2019-04-09T19:45:40.000+02:00
diff --git a/lib/matplotlib/axes/_subplots.py b/lib/matplotlib/axes/_subplots.py
@@ -48,6 +48,10 @@ def __init__(self, fig, *args, **kwargs):
             rows, cols, num = args
             rows = int(rows)
             cols = int(cols)
+            if rows <= 0:
+                raise ValueError(f'Number of rows must be > 0, not {rows}')
+            if cols <= 0:
+                raise ValueError(f'Number of columns must be > 0, not {cols}')
             if isinstance(num, tuple) and len(num) == 2:
                 num = [int(n) for n in num]
                 self._subplotspec = GridSpec(
diff --git a/lib/matplotlib/tests/test_figure.py b/lib/matplotlib/tests/test_figure.py
@@ -164,6 +164,18 @@ def test_gca():
     assert fig.gca() is ax1
 
 
+def test_add_subplot_invalid():
+    fig = plt.figure()
+    with pytest.raises(ValueError):
+        fig.add_subplot(2, 0, 1)
+    with pytest.raises(ValueError):
+        fig.add_subplot(0, 2, 1)
+    with pytest.raises(ValueError):
+        fig.add_subplot(2, 2, 0)
+    with pytest.raises(ValueError):
+        fig.add_subplot(2, 2, 5)
+
+
 @image_comparison(baseline_images=['figure_suptitle'])
 def test_suptitle():
     fig, _ = plt.subplots()
