197: Added new public.Option.get_default() method that calls Option.default_from() if it's a DefaultFrom instance, and otherwise returns Option.default (the static default value)

ipalib/public.py

@@ -90,14 +90,19 @@ class Option(plugable.Plugin):
 
     __public__ = frozenset((
         'normalize',
-        'default',
+        'get_default',
         'validate',
-        'required',
         'type',
+        'required',
+        'default',
+        'default_from',
     ))
     __rules = None
     type = unicode
     required = False
+    default = None
+    default_from = None
+
 
     def normalize(self, value):
         """
@@ -159,16 +164,12 @@ class Option(plugable.Plugin):
                 if is_rule(attr):
                     yield attr
 
-    def default(self, **kw):
-        """
-        Returns a default or auto-completed value for this Option. If no
-        default is available, this method should return None.
-
-        All the keywords are passed so it's possible to build an
-        auto-completed value from other Options values, e.g., build 'initials'
-        from 'givenname' + 'sn'.
-        """
-        return None
+    def get_default(self, **kw):
+        if type(self.default_from) is DefaultFrom:
+            default = self.default_from(**kw)
+            if default is not None:
+                return default
+        return self.default
 
 
 class Command(plugable.Plugin):

ipalib/tests/test_public.py

@@ -190,12 +190,25 @@ class test_Option(ClassChecker):
         rules = tuple(get_rule(i) for i in xrange(3))
         assert o.rules == rules
 
-    def test_default(self):
+    def test_get_default(self):
         """
-        Tests the `public.Option.default` method.
+        Tests the `public.Option.get_default` method.
         """
+        assert 'get_default' in self.cls.__public__
         assert 'default' in self.cls.__public__
-        assert self.cls().default() is None
+        assert 'default_from' in self.cls.__public__
+        assert self.cls().get_default() is None
+        class subclass(self.cls):
+            default = 3
+            default_from = public.DefaultFrom(
+                lambda a,b: a * b,
+                'key0', 'key1'
+            )
+        o = subclass()
+        assert o.get_default() == 3
+        assert o.get_default(key0=2, key1=5) == 10
+        assert o.get_default(key0=7) == 3
+
 
 
 class test_Command(ClassChecker):