Cache Python document schema catalogs

packages/cultcache-py/src/cultcache_py/documents.py

@@ -89,6 +89,7 @@ class DocumentDefinition(Generic[T]):
     canonical_schema_json: str | None = None
     compatible_schema_ids: tuple[str, ...] = field(default_factory=tuple)
     members: tuple[CultCacheSchemaCatalogMember, ...] = field(default_factory=tuple)
+    _catalog_entry: CultCacheSchemaCatalogEntry | None = field(default=None, init=False, repr=False, compare=False)
 
     def encode_payload(self, value: T) -> bytes:
         if self.validate:
@@ -102,6 +103,8 @@ class DocumentDefinition(Generic[T]):
         return value
 
     def catalog_entry(self) -> CultCacheSchemaCatalogEntry:
+        if self._catalog_entry is not None:
+            return self._catalog_entry
         schema_id = self.schema_id or self.type
         schema_name = self.schema_name or self.type
         schema_version = self.schema_version or f"{schema_name}.v1"
@@ -127,7 +130,7 @@ class DocumentDefinition(Generic[T]):
             separators=(",", ":"),
         )
         compatible_schema_ids = self.compatible_schema_ids or (schema_id,)
-        return CultCacheSchemaCatalogEntry(
+        catalog_entry = CultCacheSchemaCatalogEntry(
             schema_id=schema_id,
             schema_name=schema_name,
             schema_version=schema_version,
@@ -136,6 +139,8 @@ class DocumentDefinition(Generic[T]):
             compatible_schema_ids=tuple(compatible_schema_ids),
             members=tuple(self.members),
         )
+        object.__setattr__(self, "_catalog_entry", catalog_entry)
+        return catalog_entry
 
 
 def define_document_type(

packages/cultcache-py/tests/test_cultcache.py

@@ -190,6 +190,21 @@ class CultCacheTests(unittest.TestCase):
         self.assertEqual(msgpack.unpackb(payload, raw=False), ["ash", None, 3])
         self.assertEqual(document.decode_payload(msgpack.packb(["ash"], use_bin_type=True)).retries, 0)
 
+    def test_document_catalog_entry_is_cached_after_first_derivation(self) -> None:
+        document = define_database_entry_type(
+            "settings",
+            [
+                ("theme", 0),
+                ("retries", 2, 0),
+            ],
+        )
+
+        first = document.catalog_entry()
+        second = document.catalog_entry()
+
+        self.assertIs(first, second)
+        self.assertEqual([member.slot for member in first.members], [0, 2])
+
     def test_messagepack_store_writes_v1_snapshot(self) -> None:
         try:
             import msgpack  # type: ignore