From a03eb8492e62adbf8627c175f269693090db3c17 Mon Sep 17 00:00:00 2001
From: Eric Traut <eric@traut.com>
Date: Fri, 14 Jun 2024 09:15:34 -0700
Subject: [PATCH] Removed recent change in `dataclass_transform` handling.
 Dataclass properties should not be inherited from base classes after all. See
 https://discuss.python.org/t/dataclass-transform-inheriting-class-doesnt-recognize-kw-only-true-from-parent-class/55734/2.

---
 .../src/analyzer/typeEvaluator.ts             | 47 +++++--------------
 .../src/tests/samples/dataclassTransform5.py  | 29 ------------
 .../src/tests/typeEvaluator5.test.ts          |  6 ---
 3 files changed, 12 insertions(+), 70 deletions(-)
 delete mode 100644 packages/pyright-internal/src/tests/samples/dataclassTransform5.py

diff --git a/packages/pyright-internal/src/analyzer/typeEvaluator.ts b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
index cba58de61..a2a46759a 100644
--- a/packages/pyright-internal/src/analyzer/typeEvaluator.ts
+++ b/packages/pyright-internal/src/analyzer/typeEvaluator.ts
@@ -17071,42 +17071,19 @@ export function createTypeEvaluator(
             // Determine whether this class derives from (or has a metaclass) that imbues
             // it with dataclass-like behaviors. If so, we'll apply those here.
             let dataClassBehaviors: DataClassBehaviors | undefined;
+            if (isInstantiableClass(effectiveMetaclass) && effectiveMetaclass.details.classDataClassTransform) {
+                dataClassBehaviors = effectiveMetaclass.details.classDataClassTransform;
+            } else {
+                const baseClassDataTransform = classType.details.mro.find((mroClass) => {
+                    return (
+                        isClass(mroClass) &&
+                        mroClass.details.classDataClassTransform !== undefined &&
+                        !ClassType.isSameGenericClass(mroClass, classType)
+                    );
+                });
 
-            // If this class has not already received its dataclass behaviors from a
-            // decorator and is inheriting from a class that has dataclass behaviors,
-            // apply those inherited behaviors to this class.
-            if (!classType.details.dataClassBehaviors) {
-                for (const mroClass of classType.details.mro) {
-                    if (!isClass(mroClass)) {
-                        break;
-                    }
-
-                    if (ClassType.isSameGenericClass(mroClass, classType)) {
-                        continue;
-                    }
-
-                    if (mroClass.details.dataClassBehaviors) {
-                        dataClassBehaviors = mroClass.details.dataClassBehaviors;
-                        break;
-                    }
-                }
-            }
-
-            if (!dataClassBehaviors) {
-                if (isInstantiableClass(effectiveMetaclass) && effectiveMetaclass.details.classDataClassTransform) {
-                    dataClassBehaviors = effectiveMetaclass.details.classDataClassTransform;
-                } else {
-                    const baseClassDataTransform = classType.details.mro.find((mroClass) => {
-                        return (
-                            isClass(mroClass) &&
-                            mroClass.details.classDataClassTransform !== undefined &&
-                            !ClassType.isSameGenericClass(mroClass, classType)
-                        );
-                    });
-
-                    if (baseClassDataTransform) {
-                        dataClassBehaviors = (baseClassDataTransform as ClassType).details.classDataClassTransform;
-                    }
+                if (baseClassDataTransform) {
+                    dataClassBehaviors = (baseClassDataTransform as ClassType).details.classDataClassTransform;
                 }
             }
 
diff --git a/packages/pyright-internal/src/tests/samples/dataclassTransform5.py b/packages/pyright-internal/src/tests/samples/dataclassTransform5.py
deleted file mode 100644
index a1fdc66bf..000000000
--- a/packages/pyright-internal/src/tests/samples/dataclassTransform5.py
+++ /dev/null
@@ -1,29 +0,0 @@
-# This sample tests the case where a dataclass inherits a dataclass
-# behavior (like kw_only) from its parent class.
-
-from typing import dataclass_transform
-
-
-@dataclass_transform()
-class ModelMeta(type):
-    pass
-
-
-class ModelBase(metaclass=ModelMeta):
-    def __init_subclass__(cls, kw_only: bool = False) -> None:
-        pass
-
-
-class Base(ModelBase, kw_only=True):
-    pass
-
-
-class Model(Base):
-    a: str | None = None
-    b: int
-
-
-Model(b=0)
-
-# This should generate an error because of kw_only.
-Model("", 1)
diff --git a/packages/pyright-internal/src/tests/typeEvaluator5.test.ts b/packages/pyright-internal/src/tests/typeEvaluator5.test.ts
index bf458ba00..d4cc61be1 100644
--- a/packages/pyright-internal/src/tests/typeEvaluator5.test.ts
+++ b/packages/pyright-internal/src/tests/typeEvaluator5.test.ts
@@ -416,12 +416,6 @@ test('DataclassTransform4', () => {
     TestUtils.validateResults(analysisResults, 2);
 });
 
-test('DataclassTransform5', () => {
-    const analysisResults = TestUtils.typeAnalyzeSampleFiles(['dataclassTransform5.py']);
-
-    TestUtils.validateResults(analysisResults, 1);
-});
-
 test('Async1', () => {
     const analysisResults = TestUtils.typeAnalyzeSampleFiles(['async1.py']);