Validate member ids and targets

Author: JordonPhillips

python-packages/smithy-core/smithy_core/schemas.py

@@ -177,6 +177,9 @@ def member(
         :param target: The schema the member is targeting.
         :param index: The member's index.
         """
+        id.expect_member()
+        if target.member_target is not None:
+            raise ExpectationNotMetException("Member targets must not be members.")
         resolved_traits = target.traits.copy()
         if member_traits:
             resolved_traits.update({t.id: t for t in member_traits})

python-packages/smithy-core/tests/unit/test_schemas.py

@@ -104,3 +104,16 @@ def test_member_constructor():
     )
 
     assert actual == expected
+
+
+def test_member_constructor_asserts_id():
+    with pytest.raises(ExpectationNotMetException):
+        Schema.member(id=ShapeID("smithy.example#foo"), target=STRING, index=0)
+
+
+def test_member_constructor_asserts_target_is_not_member():
+    target = Schema.member(
+        id=ShapeID("smithy.example#Spam$eggs"), target=STRING, index=0
+    )
+    with pytest.raises(ExpectationNotMetException):
+        Schema.member(id=ShapeID("smithy.example#Foo$bar"), target=target, index=0)