owcolor: fix handling changed compute_values

Variables stored in context settings were reused when constructing new
domains. Therefore, there were problems if only their compute_values
changed because the old context (matching names and values) still
matched. After this fix the variable descriptors on the input are always
used when creating colored variables instead of the ones stored in the
context.

Also, compute_values do not need to be stored in settings and are
therefore removed.

Author: markotoplak

Orange/widgets/data/owcolor.py

@@ -42,7 +42,9 @@ class AttrDesc:
         new_name (str or `None`): a changed name or `None`
     """
     def __init__(self, var):
-        self.var = var
+        # these objects are stored within context settings;
+        # avoid storing compute_values
+        self.var = var.copy(compute_value=None)
         self.new_name = None
 
     def reset(self):
@@ -118,9 +120,9 @@ def set_value(self, i, value):
             self.new_values = list(self.var.values)
         self.new_values[i] = value
 
-    def create_variable(self):
-        new_var = self.var.copy(name=self.name, values=self.values,
-                                compute_value=Identity(self.var))
+    def create_variable(self, base_var):
+        new_var = base_var.copy(name=self.name, values=self.values,
+                                compute_value=Identity(base_var))
         new_var.colors = np.asarray(self.colors)
         return new_var
 
@@ -209,9 +211,9 @@ def palette_name(self):
     def palette_name(self, palette_name):
         self.new_palette_name = palette_name
 
-    def create_variable(self):
-        new_var = self.var.copy(name=self.name,
-                                compute_value=Identity(self.var))
+    def create_variable(self, base_var):
+        new_var = base_var.copy(name=self.name,
+                                compute_value=Identity(base_var))
         new_var.attributes["palette"] = self.palette_name
         return new_var
 
@@ -746,7 +748,7 @@ def make(variables):
             for var in variables:
                 source = disc_dict if var.is_discrete else cont_dict
                 desc = source.get(var.name)
-                new_vars.append(desc.create_variable() if desc else var)
+                new_vars.append(desc.create_variable(var) if desc else var)
             return new_vars
 
         if self.data is None:

Orange/widgets/data/tests/test_owcolor.py

@@ -31,6 +31,11 @@ def test_name(self):
         desc.name = None
         self.assertEqual(desc.name, "x")
 
+    def test_no_compute_value(self):
+        x = ContinuousVariable("x", compute_value=lambda x: 42)
+        desc = owcolor.AttrDesc(x)
+        self.assertIsNone(desc.var.compute_value)
+
     def test_reset(self):
         x = ContinuousVariable("x")
         desc = owcolor.AttrDesc(x)
@@ -89,20 +94,20 @@ def test_create_variable(self):
         desc.set_color(2, [7, 8, 9])
         desc.name = "z"
         desc.set_value(1, "d")
-        var = desc.create_variable()
+        var = desc.create_variable(self.var)
         self.assertIsInstance(var, DiscreteVariable)
         self.assertEqual(var.name, "z")
         self.assertEqual(var.values, ("a", "d", "c"))
         np.testing.assert_equal(var.colors, [[1, 2, 3], [4, 5, 6], [7, 8, 9]])
         self.assertIsInstance(var.compute_value, Identity)
-        self.assertIs(var.compute_value.variable, desc.var)
+        self.assertIs(var.compute_value.variable, self.var)
 
         palette = desc.var.attributes["palette"] = object()
-        var = desc.create_variable()
+        var = desc.create_variable(self.var)
         self.assertIs(desc.var.attributes["palette"], palette)
         self.assertFalse(hasattr(var.attributes, "palette"))
         self.assertIsInstance(var.compute_value, Identity)
-        self.assertIs(var.compute_value.variable, desc.var)
+        self.assertIs(var.compute_value.variable, self.var)
 
     def test_reset(self):
         desc = self.desc
@@ -228,8 +233,8 @@ def test_from_dict_exceptions(self):
 
 class ContAttrDescTest(unittest.TestCase):
     def setUp(self):
-        x = ContinuousVariable("x")
-        self.desc = owcolor.ContAttrDesc(x)
+        self.var = ContinuousVariable("x")
+        self.desc = owcolor.ContAttrDesc(self.var)
 
     def test_palette(self):
         desc = self.desc
@@ -246,19 +251,19 @@ def test_create_variable(self):
         palette_name = _find_other_palette(
             colorpalettes.ContinuousPalettes[desc.palette_name]).name
         desc.palette_name = palette_name
-        var = desc.create_variable()
+        var = desc.create_variable(self.var)
         self.assertIsInstance(var, ContinuousVariable)
         self.assertEqual(var.name, "z")
         self.assertEqual(var.palette.name, palette_name)
         self.assertIsInstance(var.compute_value, Identity)
-        self.assertIs(var.compute_value.variable, desc.var)
+        self.assertIs(var.compute_value.variable, self.var)
 
         colors = desc.var.attributes["colors"] = object()
-        var = desc.create_variable()
+        var = desc.create_variable(self.var)
         self.assertIs(desc.var.attributes["colors"], colors)
         self.assertFalse(hasattr(var.attributes, "colors"))
         self.assertIsInstance(var.compute_value, Identity)
-        self.assertIs(var.compute_value.variable, desc.var)
+        self.assertIs(var.compute_value.variable, self.var)
 
     def test_reset(self):
         desc = self.desc