fix for pcolormesh doesn't allow shading = 'flat' in the option

vivekvedant · vivekvedant · commit 98dd012d90e6 · 2023-01-22T23:25:59.000+05:30
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -5749,7 +5749,7 @@ def _pcolorargs(self, funcname, *args, shading='auto', **kwargs):
         if shading == 'flat':
             if (Nx, Ny) != (ncols + 1, nrows + 1):
                 raise TypeError('Dimensions of C %s are incompatible with'
-                                ' X (%d) and/or Y (%d); see help(%s)' % (
+                                ' X (%d) and/or Y (%d); X and y should be one larger than  C see help(%s)' % (
                                     C.shape, Nx, Ny, funcname))
         else:    # ['nearest', 'gouraud']:
             if (Nx, Ny) != (ncols, nrows):
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -1438,6 +1438,13 @@ def test_pcolorflaterror():
     with pytest.raises(TypeError, match='Dimensions of C'):
         ax.pcolormesh(x, y, Z, shading='flat')
 
+def test_samesizepcolorflaterror():
+    fig, ax = plt.subplots()
+    x, y = np.meshgrid(np.arange(5), np.arange(3))
+    Z = x + y
+    with pytest.raises(TypeError, match=r".*X and y should be one larger than  C"):
+        ax.pcolormesh(x, y, Z, shading='flat')
+
 
 @pytest.mark.parametrize('snap', [False, True])
 @check_figures_equal(extensions=["png"])
