Enhance BaseModel comparisons by hashing versioned and relations attributes.

[plomtask] / plomtask / db.py

diff --git a/plomtask/db.py b/plomtask/db.py
index 2077d79f22450be197aa72fbbfccbc5a35a9b2e9..a47dff15917651940483afe83f41152399bedf7f 100644 (file)
--- a/plomtask/db.py
+++ b/plomtask/db.py
@@ -245,16 +245,24 @@ class BaseModel(Generic[BaseModelId]):
         if isinstance(id_, int) and id_ < 1:
             msg = f'illegal {self.__class__.__name__} ID, must be >=1: {id_}'
             raise HandledException(msg)
+        if isinstance(id_, str) and "" == id_:
+            msg = f'illegal {self.__class__.__name__} ID, must be non-empty'
+            raise HandledException(msg)
         self.id_ = id_
 
+    def __hash__(self) -> int:
+        hashable = [self.id_] + [getattr(self, name) for name in self.to_save]
+        for definition in self.to_save_relations:
+            attr = getattr(self, definition[2])
+            hashable += [tuple(rel.id_ for rel in attr)]
+        for name in self.to_save_versioned:
+            hashable += [hash(getattr(self, name))]
+        return hash(tuple(hashable))
+
     def __eq__(self, other: object) -> bool:
         if not isinstance(other, self.__class__):
             return False
-        to_hash_me = tuple([self.id_] +
-                           [getattr(self, name) for name in self.to_save])
-        to_hash_other = tuple([other.id_] +
-                              [getattr(other, name) for name in other.to_save])
-        return hash(to_hash_me) == hash(to_hash_other)
+        return hash(self) == hash(other)
 
     def __lt__(self, other: Any) -> bool:
         if not isinstance(other, self.__class__):