From 182dd9d414355310b46e67f667924bcba9cc29ee Mon Sep 17 00:00:00 2001
From: Chip Kent <5250374+chipkent@users.noreply.github.com>
Date: Fri, 23 Oct 2026 22:15:49 -0600
Subject: [PATCH] feat: let type checkers see model constructors

@modelclass builds an __init__ that accepts every field positionally or
by keyword, but type checkers could not see it: a call such as
CryptoQuote(pair="BTC-USD", bid_price=1.5) was reported as
"Unexpected keyword argument" for every field.

Mark modelclass with dataclass_transform (PEP 681) so checkers derive
the constructor from the field annotations. The decorator is imported
only under TYPE_CHECKING, from typing on 3.11+ and from
typing_extensions on 3.10, and is a no-op at runtime, so there is no new
runtime dependency and Python 3.10 keeps working.
---
 massive/modelclass.py | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/massive/modelclass.py b/massive/modelclass.py
index 117f7910..0605180a 100644
--- a/massive/modelclass.py
+++ b/massive/modelclass.py
@@ -1,10 +1,23 @@
 import inspect
+import sys
 import typing
 from dataclasses import dataclass
 
+if typing.TYPE_CHECKING:
+    if sys.version_info >= (3, 11):
+        from typing import dataclass_transform
+    else:
+        from typing_extensions import dataclass_transform
+else:
+
+    def dataclass_transform(**kwargs):
+        return lambda f: f
+
+
 _T = typing.TypeVar("_T")
 
 
+@dataclass_transform()
 def modelclass(cls: typing.Type[_T]) -> typing.Type[_T]:
     cls = dataclass(cls)
     type_hints = typing.get_type_hints(cls)