Fix class variable not being used for vdims in RGB (#5773)

holoviews/element/raster.py

@@ -610,7 +610,8 @@ def __init__(self, data, kdims=None, vdims=None, **params):
             arrays = [(im.data - r[0]) / (r[1] - r[0]) for r,im in zip(ranges, images)]
             data = np.dstack(arrays)
         if vdims is None:
-            vdims = list(self.vdims)
+            # Same as the class variables, put here to secure the class variable is not used
+            vdims = [Dimension(c, range=(0,1)) for c in "RGB"]
         else:
             vdims = list(vdims) if isinstance(vdims, list) else [vdims]
 

holoviews/tests/element/test_raster.py

@@ -48,6 +48,11 @@ def test_construct_from_dict_with_alpha(self):
         rgb = RGB({'x': [1, 2, 3], 'y': [1, 2, 3], ('R', 'G', 'B', 'A'): self.rgb_array})
         self.assertEqual(len(rgb.vdims), 4)
 
+    def test_not_using_class_variables_vdims(self):
+        init_vdims = RGB(self.rgb_array).vdims
+        cls_vdims = RGB.vdims
+        for i, c in zip(init_vdims, cls_vdims):
+            assert i is not c
 
 class TestQuadMesh(ComparisonTestCase):