Add slots to dataclass schema

Author: hramezani

pydantic_core/core_schema.py

@@ -3101,6 +3101,7 @@ class DataclassSchema(TypedDict, total=False):
     ref: str
     metadata: Any
     serialization: SerSchema
+    slots: bool
 
 
 def dataclass_schema(
@@ -3115,6 +3116,7 @@ def dataclass_schema(
     metadata: Any = None,
     serialization: SerSchema | None = None,
     frozen: bool | None = None,
+    slots: bool = False,
 ) -> DataclassSchema:
     """
     Returns a schema for a dataclass. As with `ModelSchema`, this schema can only be used as a field within
@@ -3145,6 +3147,7 @@ def dataclass_schema(
         metadata=metadata,
         serialization=serialization,
         frozen=frozen,
+        slots=slots,
     )
 
 

src/validators/dataclass.rs

@@ -415,6 +415,7 @@ pub struct DataclassValidator {
     revalidate: Revalidate,
     name: String,
     frozen: bool,
+    slots: bool,
 }
 
 impl BuildValidator for DataclassValidator {
@@ -453,6 +454,7 @@ impl BuildValidator for DataclassValidator {
             )?)?,
             name,
             frozen: schema.get_as(intern!(py, "frozen"))?.unwrap_or(false),
+            slots: schema.get_as(intern!(py, "slots"))?.unwrap_or(false),
         }
         .into())
     }
@@ -595,7 +597,13 @@ impl DataclassValidator {
         input: &'data impl Input<'data>,
     ) -> ValResult<'data, ()> {
         let (dc_dict, post_init_kwargs): (&PyAny, &PyAny) = val_output.extract(py)?;
-        force_setattr(py, dc, intern!(py, "__dict__"), dc_dict)?;
+        if self.slots {
+            for (key, value) in dc_dict.downcast::<PyDict>()?.iter() {
+                force_setattr(py, dc, key, value)?;
+            }
+        } else {
+            force_setattr(py, dc, intern!(py, "__dict__"), dc_dict)?;
+        }
 
         if let Some(ref post_init) = self.post_init {
             let post_init = post_init.as_ref(py);

tests/test_schema_functions.py

@@ -250,7 +250,7 @@ def args(*args, **kwargs):
         core_schema.dataclass_schema,
         # MyModel should be a dataclass, but I'm being lazy here
         args(MyModel, {'type': 'int'}),
-        {'type': 'dataclass', 'schema': {'type': 'int'}, 'cls': MyModel},
+        {'type': 'dataclass', 'schema': {'type': 'int'}, 'cls': MyModel, 'slots': False},
     ),
 ]