Removed support for transform_descriptor_types parameter in `datacl…

…ass_transform`, a feature that was determined to be not necessary. Added support on normal dataclass handling for field types that are custom descriptor objects.
microsoft · Mar 27, 2022 · 368dc5e · 368dc5e
1 parent 9558239
commit 368dc5e
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Showing 6 changed files with 53 additions and 98 deletions.
diff --git a/packages/pyright-internal/src/analyzer/dataClasses.ts b/packages/pyright-internal/src/analyzer/dataClasses.ts
@@ -401,9 +401,9 @@ export function synthesizeDataClassMethods(
                     effectiveType = applySolvedTypeVars(effectiveType, typeVarMap);
                 }
 
-                if (classType.details.dataClassBehaviors?.transformDescriptorTypes) {
-                    effectiveType = transformDescriptorType(evaluator, effectiveType);
-                }
+                // Is the field type a descriptor object? If so, we need to extract the corresponding
+                // type of the __init__ method parameter from the __set__ method.
+                effectiveType = transformDescriptorType(evaluator, effectiveType);
 
                 const functionParam: FunctionParameter = {
                     category: ParameterCategory.Simple,
@@ -631,7 +631,6 @@ export function validateDataClassTransformDecorator(
         keywordOnlyParams: false,
         generateEq: true,
         generateOrder: false,
-        transformDescriptorTypes: false,
         fieldDescriptorNames: [],
     };
 
@@ -687,20 +686,6 @@ export function validateDataClassTransformDecorator(
                 break;
             }
 
-            case 'transform_descriptor_types': {
-                const value = evaluateStaticBoolExpression(arg.valueExpression, fileInfo.executionEnvironment);
-                if (value === undefined) {
-                    evaluator.addError(
-                        Localizer.Diagnostic.dataClassTransformExpectedBoolLiteral(),
-                        arg.valueExpression
-                    );
-                    return;
-                }
-
-                behaviors.transformDescriptorTypes = value;
-                break;
-            }
-
             case 'field_descriptors': {
                 const valueType = evaluator.getTypeOfExpression(arg.valueExpression).type;
                 if (
@@ -770,7 +755,6 @@ export function getDataclassDecoratorBehaviors(type: Type): DataClassBehaviors |
             keywordOnlyParams: false,
             generateEq: true,
             generateOrder: false,
-            transformDescriptorTypes: false,
             fieldDescriptorNames: ['dataclasses.field', 'dataclasses.Field'],
         };
     }

diff --git a/packages/pyright-internal/src/analyzer/types.ts b/packages/pyright-internal/src/analyzer/types.ts
@@ -416,7 +416,6 @@ export interface DataClassBehaviors {
     keywordOnlyParams: boolean;
     generateEq: boolean;
     generateOrder: boolean;
-    transformDescriptorTypes: boolean;
     fieldDescriptorNames: string[];
 }
 

diff --git a/packages/pyright-internal/src/tests/samples/dataclass19.py b/packages/pyright-internal/src/tests/samples/dataclass19.py
@@ -0,0 +1,44 @@
+# This sample tests the handling of dataclass fields that use
+# descriptor objects.
+
+from dataclasses import dataclass
+from typing import Any, cast, overload
+
+
+class MyDescriptor:
+    @overload
+    def __get__(self, __obj: None, __owner: Any) -> "MyDescriptor":
+        ...
+
+    @overload
+    def __get__(self, __obj: object, __owner: Any) -> int:
+        ...
+
+    def __get__(self, __obj: object | None, __owner: Any) -> "int | MyDescriptor":
+        if __obj is None:
+            return self
+        return cast(Any, __obj)._x
+
+    def __set__(self, __obj: object, __value: int) -> None:
+        if __obj is not None:
+            cast(Any, __obj)._x = __value
+
+
+@dataclass
+class Foo:
+    y: MyDescriptor = MyDescriptor()
+
+
+f1 = Foo(3)
+
+reveal_type(f1.y, expected_text="int")
+reveal_type(Foo.y, expected_text="MyDescriptor")
+
+
+# This should generate an error.
+f2 = Foo("hi")
+
+
+f3 = Foo()
+reveal_type(f3.y, expected_text="int")
+
diff --git a/packages/pyright-internal/src/tests/samples/dataclassTransform5.py b/packages/pyright-internal/src/tests/samples/dataclassTransform5.py
diff --git a/packages/pyright-internal/src/tests/typeEvaluator3.test.ts b/packages/pyright-internal/src/tests/typeEvaluator3.test.ts
@@ -1191,12 +1191,6 @@ test('DataclassTransform4', () => {
     TestUtils.validateResults(analysisResults, 1);
 });
 
-test('DataclassTransform5', () => {
-    const analysisResults = TestUtils.typeAnalyzeSampleFiles(['dataclassTransform5.py']);
-
-    TestUtils.validateResults(analysisResults, 1);
-});
-
 test('Async1', () => {
     const analysisResults = TestUtils.typeAnalyzeSampleFiles(['async1.py']);
 

diff --git a/packages/pyright-internal/src/tests/typeEvaluator4.test.ts b/packages/pyright-internal/src/tests/typeEvaluator4.test.ts
@@ -561,6 +561,12 @@ test('DataClass18', () => {
     TestUtils.validateResults(analysisResults, 2);
 });
 
+test('DataClass19', () => {
+    const analysisResults = TestUtils.typeAnalyzeSampleFiles(['dataclass19.py']);
+
+    TestUtils.validateResults(analysisResults, 1);
+});
+
 test('DataClassPostInit1', () => {
     const analysisResults = TestUtils.typeAnalyzeSampleFiles(['dataclassPostInit1.py']);