Fix regression that ignored allow_None set in a selector

param/__init__.py

@@ -1691,6 +1691,8 @@ def __init__(self, *, objects=Undefined, default=Undefined, instantiate=Undefine
         # Required as Parameter sets allow_None=True if default is None
         if allow_None is Undefined:
             self.allow_None = self._slot_defaults['allow_None']
+        else:
+            self.allow_None = allow_None
         if self.default is not None and self.check_on_set is True:
             self._validate(self.default)
 

tests/testobjectselector.py

@@ -10,6 +10,7 @@
 from collections import OrderedDict
 
 import param
+import pytest
 
 from .utils import check_defaults
 
@@ -104,6 +105,51 @@ def test_unbound_allow_None_not_dynamic(self):
 
         assert s.allow_None is None
 
+    def test_allow_None_set_and_behavior_class(self):
+        class P(param.Parameterized):
+            a = param.ObjectSelector(objects=dict(a=1), allow_None=True)
+            b = param.ObjectSelector(objects=dict(a=1), allow_None=False)
+            c = param.ObjectSelector(default=1, objects=dict(a=1), allow_None=True)
+            d = param.ObjectSelector(default=1, objects=dict(a=1), allow_None=False)
+
+        assert P.param.a.allow_None is True
+        assert P.param.b.allow_None is False
+        assert P.param.c.allow_None is True
+        assert P.param.d.allow_None is False
+
+        P.a = None
+        assert P.a is None
+        with pytest.raises(ValueError):
+            P.b = None
+        P.c = None
+        assert P.c is None
+        with pytest.raises(ValueError):
+            P.d = None
+
+    def test_allow_None_set_and_behavior_instance(self):
+        class P(param.Parameterized):
+            a = param.ObjectSelector(objects=dict(a=1), allow_None=True)
+            b = param.ObjectSelector(objects=dict(a=1), allow_None=False)
+            c = param.ObjectSelector(default=1, objects=dict(a=1), allow_None=True)
+            d = param.ObjectSelector(default=1, objects=dict(a=1), allow_None=False)
+
+        p = P()
+
+        assert p.param.a.allow_None is True
+        assert p.param.b.allow_None is False
+        assert p.param.c.allow_None is True
+        assert p.param.d.allow_None is False
+
+        p.a = None
+        assert p.a is None
+        with pytest.raises(ValueError):
+            p.b = None
+        p.c = None
+        assert p.c is None
+        with pytest.raises(ValueError):
+            p.d = None
+
+
     def test_set_object_constructor(self):
         p = self.P(e=6)
         self.assertEqual(p.e, 6)

tests/testselector.py

@@ -9,8 +9,9 @@
 from collections import OrderedDict
 
 import param
+import pytest
 
-from.utils import check_defaults
+from .utils import check_defaults
 
 opts=dict(A=[1,2],B=[3,4],C=dict(a=1,b=2))
 
@@ -103,6 +104,50 @@ def test_allow_None_is_None(self):
         assert p.param.s.allow_None is None
         assert p.param.d.allow_None is None
 
+    def test_allow_None_set_and_behavior_class(self):
+        class P(param.Parameterized):
+            a = param.Selector(objects=dict(a=1), allow_None=True)
+            b = param.Selector(objects=dict(a=1), allow_None=False)
+            c = param.Selector(default=1, objects=dict(a=1), allow_None=True)
+            d = param.Selector(default=1, objects=dict(a=1), allow_None=False)
+
+        assert P.param.a.allow_None is True
+        assert P.param.b.allow_None is False
+        assert P.param.c.allow_None is True
+        assert P.param.d.allow_None is False
+
+        P.a = None
+        assert P.a is None
+        with pytest.raises(ValueError):
+            P.b = None
+        P.c = None
+        assert P.c is None
+        with pytest.raises(ValueError):
+            P.d = None
+
+    def test_allow_None_set_and_behavior_instance(self):
+        class P(param.Parameterized):
+            a = param.Selector(objects=dict(a=1), allow_None=True)
+            b = param.Selector(objects=dict(a=1), allow_None=False)
+            c = param.Selector(default=1, objects=dict(a=1), allow_None=True)
+            d = param.Selector(default=1, objects=dict(a=1), allow_None=False)
+
+        p = P()
+
+        assert p.param.a.allow_None is True
+        assert p.param.b.allow_None is False
+        assert p.param.c.allow_None is True
+        assert p.param.d.allow_None is False
+
+        p.a = None
+        assert p.a is None
+        with pytest.raises(ValueError):
+            p.b = None
+        p.c = None
+        assert p.c is None
+        with pytest.raises(ValueError):
+            p.d = None
+
     def test_autodefault(self):
         class P(param.Parameterized):
             o1 = param.Selector(objects=[6, 7])