IdSync: add more asserts and value checks #25

* syncing an emtpy model is illegal
* UIDs in a JSON are unique
* IDs are set on "on_sync()"

Author: greenrobot

objectbox/model/entity.py

@@ -55,6 +55,7 @@ def has_uid(self) -> bool:
 
     def on_sync(self):
         """ Method called once ID/UID are synced with the model file. """
+        assert self.iduid.is_assigned()
         for prop in self.properties:
             prop.on_sync()
 

objectbox/model/idsync.py

@@ -18,6 +18,8 @@ class IdSync:
 
     def __init__(self, model: Model, model_json_filepath: str):
         self.model = model
+        if len(model.entities) == 0:
+            raise ValueError("A valid model must have at least one entity")
 
         self.model_filepath = model_json_filepath
         self.model_json = None
@@ -42,11 +44,22 @@ def _load_model_json(self):
 
     def _load_assigned_uids(self):
         for entity_json in self.model_json["entities"]:
-            self._assigned_uids.add(IdUid.from_str(entity_json["id"]).uid)
+            entity_uid = IdUid.from_str(entity_json["id"]).uid
+            if entity_uid in self._assigned_uids:
+                raise ValueError(f"An entity's UID {entity_uid} has already been used elsewhere")
+            self._assigned_uids.add(entity_uid)
+
             for prop_json in entity_json["properties"]:
-                self._assigned_uids.add(IdUid.from_str(prop_json["id"]).uid)
+                prop_uid = IdUid.from_str(prop_json["id"]).uid
+                if prop_uid in self._assigned_uids:
+                    raise ValueError(f"A property's UID {prop_uid} has already been used elsewhere")
+                self._assigned_uids.add(prop_uid)
+
                 if "indexId" in prop_json:
-                    self._assigned_uids.add(IdUid.from_str(prop_json["indexId"]).uid)
+                    index_uid = IdUid.from_str(prop_json["indexId"]).uid
+                    if index_uid in self._assigned_uids:
+                        raise ValueError(f"An index's UID {index_uid} has already been used elsewhere")
+                    self._assigned_uids.add(index_uid)
 
     def _save_model_json(self):
         """ Replaces model JSON with the serialized model whose ID/UIDs are assigned. """

objectbox/model/properties.py

@@ -201,6 +201,7 @@ def is_id(self) -> bool:
 
     def on_sync(self):
         """ Method called once ID/UID are synced with the model file. """
+        assert self.iduid.is_assigned()
         self._fb_slot = self.id - 1
         self._fb_v_offset = 4 + 2 * self._fb_slot
 

tests/test_idsync.py

@@ -54,7 +54,8 @@ def test_empty_model(env):
 
     # JSON file didn't exist, user syncs an empty model -> no JSON file is generated
     model = Model()
-    assert not env.sync(model)
+    with pytest.raises(ValueError):
+        assert not env.sync(model)
     assert not path.exists(env.model_path)
 
     # Init the JSON file with an entity
@@ -65,31 +66,14 @@ class MyEntity:
     model.entity(MyEntity)
     assert env.sync(model)  # Model JSON written
 
-    # JSON file exists, user syncs an empty model -> JSON file is written but entities are cleared (last ID/UID
-    # retained)
+    # JSON file exists, user tries to sync an empty model: must fail with JSON file untouched
     model = Model()
-    assert env.sync(model)
+    with pytest.raises(ValueError):
+       env.sync(model)
 
     doc = env.json()
-    assert doc['_note1']
-    assert doc['_note2']
-    assert doc['_note3']
-    assert len(doc['entities']) == 0
-    # Last entity ID/UID will still be set at MyEntity's ID/UID
-    # assert doc['lastEntityId'] == '0:0'
-    # assert doc['lastIndexId'] == '0:0'  # NOTE: objectbox-generator outputs ""
-    assert doc['modelVersionParserMinimum'] >= 5
-    # debug: pprint(doc)
-    #
-    # TODO: sync with objectbox-generator empty fbs
-    # assert doc['modelVersion'] == 5
-    # assert doc['lastIndex'] == ""
-    # assert doc['lastRelationId'] == ""
-    # assert len(doc['retiredEntityUids']) == 0
-    # assert len(doc['retiredIndexUids']) == 0
-    # assert len(doc['retiredPropertyUids']) == 0
-    # assert len(doc['retiredRelationUids']) == 0
-    # assert len(doc['version']) == 1
+    assert len(doc['entities']) == 1
+    assert doc['entities'][0]['id'] == str(MyEntity.iduid)
 
 
 def test_json(env):
@@ -311,6 +295,8 @@ class Entity4:
         name = String()  # Add one property also
 
     model = Model()
+    reset_ids(Entity1)
+    reset_ids(Entity3)
     model.entity(Entity1)
     model.entity(Entity3)
     model.entity(Entity4)