fixed reporting on undefined list attributes

src/inmanta/ast/attribute.py

@@ -22,7 +22,6 @@
 from inmanta.execute.util import Unknown
 from typing import List
 
-
 try:
     from typing import TYPE_CHECKING
 except ImportError:
@@ -49,6 +48,7 @@ def __init__(self, entity: "Entity", value_type: "Type", name: str, multi: bool=
         self.__type = value_type
         self.__multi = multi
         self.__nullallble = nullable
+        self.low = 0 if nullable else 1
         self.comment = None  # type: str
 
     def get_type(self) -> "Type":

src/inmanta/execute/runtime.py

@@ -658,7 +658,9 @@ def final(self, excns):
                     attr = self.type.get_attribute(k)
                     if attr.is_multi():
                         low = attr.low
-                        length = len(v.value)
+                        # none for list attributes
+                        # list for n-ary relations
+                        length = 0 if v.value is None else len(v.value)
                         excns.append(UnsetException(
                             "The object %s is not complete: attribute %s (%s) requires %d values but only %d are set" %
                             (self, k, attr.location, low, length), self, attr))

tests/test_compiler_errors.py

@@ -382,3 +382,18 @@ def test_610_multi_add(snippetcompiler):
         """,
         "The object __config__::A (instantiated at {dir}/main.cf:13) is not complete:"
         " attribute b ({dir}/main.cf:11:11) requires 2 values but only 1 are set")
+
+
+def test_653_list_attribute_unset(snippetcompiler):
+    snippetcompiler.setup_for_error(
+        """
+        entity Test:
+            string[] bla
+        end
+
+        Test()
+
+        implement Test using std::none
+        """,
+        "The object __config__::Test (instantiated at {dir}/main.cf:6) is not complete:"
+        " attribute bla ({dir}/main.cf:3) requires 1 values but only 0 are set")