From 6e515ed9b89faa7da4c6af0a7ce6f05f6c6fe1de Mon Sep 17 00:00:00 2001
From: Mikhail Golubev <mikhail.golubev@jetbrains.com>
Date: Mon, 9 Dec 2024 14:51:06 +0200
Subject: [PATCH] PY-77433 Don't report mutable field defaults in
 dataclass_transform-based dataclasses

Some dataclass implementations, such as Pydantic, allow declaring fields with
mutable defaults, deep-copying them under the hood.

See https://docs.pydantic.dev/latest/concepts/models/#fields-with-non-hashable-default-values


(cherry picked from commit e495621858950976226731dddbb01af4012704fa)

IJ-CR-151192

GitOrigin-RevId: 7412272584a4c26e404d3d84e6150f974027eca7
---
 .../python/inspections/PyDataclassInspection.kt    | 13 +++++++++++--
 .../a.py                                           | 14 +++++++-------
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/python/python-psi-impl/src/com/jetbrains/python/inspections/PyDataclassInspection.kt b/python/python-psi-impl/src/com/jetbrains/python/inspections/PyDataclassInspection.kt
index 1072fe8457a2..e6b7f3cd48b5 100644
--- a/python/python-psi-impl/src/com/jetbrains/python/inspections/PyDataclassInspection.kt
+++ b/python/python-psi-impl/src/com/jetbrains/python/inspections/PyDataclassInspection.kt
@@ -60,8 +60,17 @@ class PyDataclassInspection : PyInspection() {
       val dataclassParameters = parseDataclassParameters(node, myTypeEvalContext)
 
       if (dataclassParameters != null) {
-        if (dataclassParameters.type.asPredefinedType == PyDataclassParameters.PredefinedType.STD ||
-            dataclassParameters.type.asPredefinedType == PyDataclassParameters.PredefinedType.DATACLASS_TRANSFORM) {
+        if (dataclassParameters.type.asPredefinedType == PyDataclassParameters.PredefinedType.DATACLASS_TRANSFORM) {
+          processDataclassParameters(node, dataclassParameters)
+
+          node.processClassLevelDeclarations { element, _ ->
+            if (element is PyTargetExpression) {
+              processFieldFunctionCall(node, dataclassParameters, element)
+            }
+            true
+          }
+        }
+        else if (dataclassParameters.type.asPredefinedType == PyDataclassParameters.PredefinedType.STD) {
           processDataclassParameters(node, dataclassParameters)
 
           val postInit = node.findMethodByName(Dataclasses.DUNDER_POST_INIT, false, myTypeEvalContext)
diff --git a/python/testData/inspections/PyDataclassInspection/MutableDefaultFieldValueDataclassTransform/a.py b/python/testData/inspections/PyDataclassInspection/MutableDefaultFieldValueDataclassTransform/a.py
index 1eb85248a92f..61790553b71f 100644
--- a/python/testData/inspections/PyDataclassInspection/MutableDefaultFieldValueDataclassTransform/a.py
+++ b/python/testData/inspections/PyDataclassInspection/MutableDefaultFieldValueDataclassTransform/a.py
@@ -6,19 +6,19 @@ from decorator import my_dataclass, field
 
 @my_dataclass()
 class A:
-    a: list[int] = <error descr="Mutable default '[]' is not allowed. Use 'default_factory'">[]</error>
-    b: list[int] = <error descr="Mutable default 'list()' is not allowed. Use 'default_factory'">list()</error>
-    c: set[int] = <error descr="Mutable default '{1}' is not allowed. Use 'default_factory'">{1}</error>
-    d: set[int] = <error descr="Mutable default 'set()' is not allowed. Use 'default_factory'">set()</error>
+    a: list[int] = []
+    b: list[int] = list()
+    c: set[int] = {1}
+    d: set[int] = set()
     e: tuple[int, ...] = ()
     f: tuple[int, ...] = tuple()
     g: ClassVar[list[int]] = []
     h: ClassVar = []
-    i: dict[int, int] = <error descr="Mutable default '{1: 2}' is not allowed. Use 'default_factory'">{1: 2}</error>
-    j: dict[int, int] = <error descr="Mutable default 'dict()' is not allowed. Use 'default_factory'">dict()</error>
+    i: dict[int, int] = {1: 2}
+    j: dict[int, int] = dict()
     k = []
     l = list()
-    m: dict[int, int] = <error descr="Mutable default 'OrderedDict()' is not allowed. Use 'default_factory'">OrderedDict()</error>
+    m: dict[int, int] = OrderedDict()
     n: frozenset[int] = frozenset()
     o: list = field(default_factory=list)
     a2: type[list[int]] = list