Add validate_core_schema function and remove validation from `Schem…

…aValidator` and `SchemaSerializer` constructors (#982)

Co-authored-by: Adrian Garcia Badaracco <1755071+adriangb@users.noreply.github.com>

benches/main.rs

@@ -7,10 +7,11 @@ use test::{black_box, Bencher};
 use pyo3::prelude::*;
 use pyo3::types::{PyDict, PyString};
 
-use _pydantic_core::SchemaValidator;
+use _pydantic_core::{validate_core_schema, SchemaValidator};
 
 fn build_schema_validator_with_globals(py: Python, code: &str, globals: Option<&PyDict>) -> SchemaValidator {
-    let schema: &PyDict = py.eval(code, globals, None).unwrap().extract().unwrap();
+    let mut schema: &PyDict = py.eval(code, globals, None).unwrap().extract().unwrap();
+    schema = validate_core_schema(py, schema).unwrap().extract().unwrap();
     SchemaValidator::py_new(py, schema, None).unwrap()
 }
 
@@ -444,7 +445,8 @@ fn complete_model(bench: &mut Bencher) {
         sys_path.call_method1("append", ("./tests/benchmarks/",)).unwrap();
 
         let complete_schema = py.import("complete_schema").unwrap();
-        let schema = complete_schema.call_method0("schema").unwrap();
+        let mut schema = complete_schema.call_method0("schema").unwrap();
+        schema = validate_core_schema(py, schema).unwrap().extract().unwrap();
         let validator = SchemaValidator::py_new(py, schema, None).unwrap();
 
         let input = complete_schema.call_method0("input_data_lax").unwrap();

python/pydantic_core/__init__.py

@@ -24,6 +24,7 @@
     __version__,
     to_json,
     to_jsonable_python,
+    validate_core_schema,
 )
 from .core_schema import CoreConfig, CoreSchema, CoreSchemaType, ErrorType
 
@@ -63,6 +64,7 @@
     'TzInfo',
     'to_json',
     'to_jsonable_python',
+    'validate_core_schema',
 ]
 
 

python/pydantic_core/_pydantic_core.pyi

@@ -44,6 +44,7 @@ __all__ = [
     'to_jsonable_python',
     'list_all_errors',
     'TzInfo',
+    'validate_core_schema',
 ]
 __version__: str
 build_profile: str
@@ -836,3 +837,11 @@ class TzInfo(datetime.tzinfo):
     def dst(self, _dt: datetime.datetime | None) -> datetime.timedelta: ...
     def fromutc(self, dt: datetime.datetime) -> datetime.datetime: ...
     def __deepcopy__(self, _memo: dict[Any, Any]) -> 'TzInfo': ...
+
+def validate_core_schema(schema: CoreSchema) -> CoreSchema:
+    """Validate a CoreSchema
+    This currently uses lax mode for validation (i.e. will coerce strings to dates and such)
+    but may use strict mode in the future.
+    We may also remove this function altogether, do not rely on it being present if you are
+    using pydantic-core directly.
+    """

src/lib.rs

@@ -34,7 +34,7 @@ pub use errors::{
 pub use serializers::{
     to_json, to_jsonable_python, PydanticSerializationError, PydanticSerializationUnexpectedValue, SchemaSerializer,
 };
-pub use validators::{PySome, SchemaValidator};
+pub use validators::{validate_core_schema, PySome, SchemaValidator};
 
 pub fn get_pydantic_core_version() -> &'static str {
     static PYDANTIC_CORE_VERSION: OnceLock<String> = OnceLock::new();
@@ -97,5 +97,6 @@ fn _pydantic_core(py: Python, m: &PyModule) -> PyResult<()> {
     m.add_function(wrap_pyfunction!(to_json, m)?)?;
     m.add_function(wrap_pyfunction!(to_jsonable_python, m)?)?;
     m.add_function(wrap_pyfunction!(list_all_errors, m)?)?;
+    m.add_function(wrap_pyfunction!(validate_core_schema, m)?)?;
     Ok(())
 }

src/serializers/mod.rs

@@ -7,7 +7,6 @@ use pyo3::{PyTraverseError, PyVisit};
 
 use crate::definitions::DefinitionsBuilder;
 use crate::py_gc::PyGcTraverse;
-use crate::validators::SelfValidator;
 
 use config::SerializationConfig;
 pub use errors::{PydanticSerializationError, PydanticSerializationUnexpectedValue};
@@ -73,9 +72,7 @@ impl SchemaSerializer {
 #[pymethods]
 impl SchemaSerializer {
     #[new]
-    pub fn py_new(py: Python, schema: &PyDict, config: Option<&PyDict>) -> PyResult<Self> {
-        let self_validator = SelfValidator::new(py)?;
-        let schema = self_validator.validate_schema(py, schema)?;
+    pub fn py_new(schema: &PyDict, config: Option<&PyDict>) -> PyResult<Self> {
         let mut definitions_builder = DefinitionsBuilder::new();
 
         let serializer = CombinedSerializer::build(schema.downcast()?, config, &mut definitions_builder)?;

src/validators/mod.rs

@@ -113,9 +113,6 @@ pub struct SchemaValidator {
 impl SchemaValidator {
     #[new]
     pub fn py_new(py: Python, schema: &PyAny, config: Option<&PyDict>) -> PyResult<Self> {
-        let self_validator = SelfValidator::new(py)?;
-        let schema = self_validator.validate_schema(py, schema)?;
-
         let mut definitions_builder = DefinitionsBuilder::new();
 
         let mut validator = build_validator(schema, config, &mut definitions_builder)?;
@@ -411,6 +408,12 @@ impl<'py> SelfValidator<'py> {
     }
 }
 
+#[pyfunction]
+pub fn validate_core_schema<'a>(py: Python<'a>, schema: &'a PyAny) -> PyResult<&'a PyAny> {
+    let self_validator = SelfValidator::new(py)?;
+    self_validator.validate_schema(py, schema)
+}
+
 pub trait BuildValidator: Sized {
     const EXPECTED_TYPE: &'static str;
 

src/validators/string.rs

@@ -239,8 +239,8 @@ enum RegexEngine {
 }
 
 impl RegexEngine {
-    const RUST_REGEX: &str = "rust-regex";
-    const PYTHON_RE: &str = "python-re";
+    const RUST_REGEX: &'static str = "rust-regex";
+    const PYTHON_RE: &'static str = "python-re";
 }
 
 impl Pattern {

tests/benchmarks/test_complete_benchmark.py

@@ -8,15 +8,15 @@
 
 import pytest
 
-from pydantic_core import SchemaValidator, ValidationError
+from pydantic_core import SchemaValidator, ValidationError, validate_core_schema
 
 from .complete_schema import input_data_lax, input_data_strict, input_data_wrong, schema
 
 
 def test_complete_valid():
     lax_schema = schema()
     cls = lax_schema['cls']
-    lax_validator = SchemaValidator(lax_schema)
+    lax_validator = SchemaValidator(validate_core_schema(lax_schema))
     output = lax_validator.validate_python(input_data_lax())
     assert isinstance(output, cls)
     assert len(output.__pydantic_fields_set__) == 41
@@ -73,34 +73,34 @@ def test_complete_valid():
         },
     }
 
-    strict_validator = SchemaValidator(schema(strict=True))
+    strict_validator = SchemaValidator(validate_core_schema(schema(strict=True)))
     output2 = strict_validator.validate_python(input_data_strict())
     assert output_dict == output2.__dict__
 
 
 def test_complete_invalid():
     lax_schema = schema()
-    lax_validator = SchemaValidator(lax_schema)
+    lax_validator = SchemaValidator(validate_core_schema(lax_schema))
     with pytest.raises(ValidationError) as exc_info:
         lax_validator.validate_python(input_data_wrong())
     assert len(exc_info.value.errors(include_url=False)) == 739
 
 
 @pytest.mark.benchmark(group='complete')
 def test_complete_core_lax(benchmark):
-    v = SchemaValidator(schema())
+    v = SchemaValidator(validate_core_schema(schema()))
     benchmark(v.validate_python, input_data_lax())
 
 
 @pytest.mark.benchmark(group='complete')
 def test_complete_core_strict(benchmark):
-    v = SchemaValidator(schema(strict=True))
+    v = SchemaValidator(validate_core_schema(schema(strict=True)))
     benchmark(v.validate_python, input_data_strict())
 
 
 @pytest.mark.benchmark(group='complete-wrong')
 def test_complete_core_error(benchmark):
-    v = SchemaValidator(schema())
+    v = SchemaValidator(validate_core_schema(schema()))
     data = input_data_wrong()
 
     @benchmark
@@ -115,7 +115,7 @@ def f():
 
 @pytest.mark.benchmark(group='complete-wrong')
 def test_complete_core_isinstance(benchmark):
-    v = SchemaValidator(schema())
+    v = SchemaValidator(validate_core_schema(schema()))
     data = input_data_wrong()
     assert v.isinstance_python(data) is False
 
@@ -135,12 +135,12 @@ def default_json_encoder(obj):
 
 @pytest.mark.benchmark(group='complete-json')
 def test_complete_core_json(benchmark):
-    v = SchemaValidator(schema())
+    v = SchemaValidator(validate_core_schema(schema()))
     json_data = json.dumps(input_data_lax(), default=default_json_encoder)
     benchmark(v.validate_json, json_data)
 
 
 @pytest.mark.benchmark(group='build')
 def test_build_schema(benchmark):
     lax_schema = schema()
-    benchmark(SchemaValidator, lax_schema)
+    benchmark(lambda s: SchemaValidator(validate_core_schema(s)), lax_schema)

tests/conftest.py

@@ -13,7 +13,7 @@
 import pytest
 from typing_extensions import Literal
 
-from pydantic_core import ArgsKwargs, SchemaValidator, ValidationError
+from pydantic_core import ArgsKwargs, SchemaValidator, ValidationError, validate_core_schema
 from pydantic_core.core_schema import CoreConfig
 
 __all__ = 'Err', 'PyAndJson', 'plain_repr', 'infinite_generator'
@@ -53,7 +53,7 @@ class PyAndJsonValidator:
     def __init__(
         self, schema, config: CoreConfig | None = None, *, validator_type: Literal['json', 'python'] | None = None
     ):
-        self.validator = SchemaValidator(schema, config)
+        self.validator = SchemaValidator(validate_core_schema(schema), config)
         self.validator_type = validator_type
 
     def validate_python(self, py_input, strict: bool | None = None, context: Any = None):

tests/serializers/test_definitions.py

@@ -1,6 +1,6 @@
 import pytest
 
-from pydantic_core import SchemaError, SchemaSerializer, core_schema
+from pydantic_core import SchemaError, SchemaSerializer, core_schema, validate_core_schema
 
 
 def test_custom_ser():
@@ -25,7 +25,7 @@ def test_ignored_def():
 
 def test_def_error():
     with pytest.raises(SchemaError) as exc_info:
-        SchemaSerializer(
+        validate_core_schema(
             core_schema.definitions_schema(
                 core_schema.list_schema(core_schema.definition_reference_schema('foobar')),
                 [core_schema.int_schema(ref='foobar'), {'type': 'wrong'}],

tests/serializers/test_dict.py

@@ -3,7 +3,7 @@
 import pytest
 from dirty_equals import IsStrictDict
 
-from pydantic_core import SchemaError, SchemaSerializer, core_schema
+from pydantic_core import SchemaError, SchemaSerializer, core_schema, validate_core_schema
 
 
 def test_dict_str_int():
@@ -155,4 +155,6 @@ def test_filter_runtime_int():
 )
 def test_include_error(include_value, error_msg):
     with pytest.raises(SchemaError, match=error_msg):
-        SchemaSerializer(core_schema.dict_schema(serialization=core_schema.filter_dict_schema(include=include_value)))
+        validate_core_schema(
+            core_schema.dict_schema(serialization=core_schema.filter_dict_schema(include=include_value))
+        )

tests/serializers/test_list_tuple.py

@@ -4,7 +4,7 @@
 
 import pytest
 
-from pydantic_core import SchemaError, SchemaSerializer, core_schema
+from pydantic_core import SchemaError, SchemaSerializer, core_schema, validate_core_schema
 
 
 def test_list_any():
@@ -144,8 +144,10 @@ def test_exclude(schema_func, seq_f):
 @pytest.mark.parametrize('include,exclude', [({1, 3, 5}, {5, 6}), ([1, 3, 5], [5, 6])])
 def test_filter(include, exclude):
     v = SchemaSerializer(
-        core_schema.list_schema(
-            core_schema.any_schema(), serialization=core_schema.filter_seq_schema(include=include, exclude=exclude)
+        validate_core_schema(
+            core_schema.list_schema(
+                core_schema.any_schema(), serialization=core_schema.filter_seq_schema(include=include, exclude=exclude)
+            )
         )
     )
     assert v.to_python([0, 1, 2, 3, 4, 5, 6, 7]) == [1, 3]
@@ -186,7 +188,7 @@ class RemovedContains(ImplicitContains):
 @pytest.mark.parametrize('schema_func', [core_schema.list_schema, core_schema.tuple_variable_schema])
 def test_include_error(schema_func, include_value, error_msg):
     with pytest.raises(SchemaError, match=error_msg):
-        SchemaSerializer(
+        validate_core_schema(
             schema_func(core_schema.any_schema(), serialization=core_schema.filter_seq_schema(include=include_value))
         )
 

tests/serializers/test_misc.py

@@ -1,6 +1,6 @@
 import pytest
 
-from pydantic_core import SchemaError, SchemaSerializer, core_schema
+from pydantic_core import SchemaError, core_schema, validate_core_schema
 
 
 @pytest.mark.parametrize(
@@ -12,4 +12,4 @@
 )
 def test_invalid_ser_schema(ser_schema, msg):
     with pytest.raises(SchemaError, match=msg):
-        SchemaSerializer(core_schema.any_schema(serialization=ser_schema))
+        validate_core_schema(core_schema.any_schema(serialization=ser_schema))

tests/test.rs

@@ -46,7 +46,7 @@ mod tests {
                 ]
             }"#;
             let schema: &PyDict = py.eval(code, None, None).unwrap().extract().unwrap();
-            SchemaSerializer::py_new(py, schema, None).unwrap();
+            SchemaSerializer::py_new(schema, None).unwrap();
         });
     }
 
@@ -77,7 +77,7 @@ a = A()
             py.run(code, None, Some(locals)).unwrap();
             let a: &PyAny = locals.get_item("a").unwrap().extract().unwrap();
             let schema: &PyDict = locals.get_item("schema").unwrap().extract().unwrap();
-            let serialized: Vec<u8> = SchemaSerializer::py_new(py, schema, None)
+            let serialized: Vec<u8> = SchemaSerializer::py_new(schema, None)
                 .unwrap()
                 .to_json(py, a, None, None, None, true, false, false, false, false, true, None)
                 .unwrap()

tests/test_build.py

@@ -2,23 +2,23 @@
 
 import pytest
 
-from pydantic_core import SchemaError, SchemaValidator
+from pydantic_core import SchemaError, SchemaValidator, validate_core_schema
 from pydantic_core import core_schema as cs
 
 
 def test_build_error_type():
     with pytest.raises(SchemaError, match="Input tag 'foobar' found using 'type' does not match any of the"):
-        SchemaValidator({'type': 'foobar', 'title': 'TestModel'})
+        validate_core_schema({'type': 'foobar', 'title': 'TestModel'})
 
 
 def test_build_error_internal():
     with pytest.raises(SchemaError, match='Input should be a valid integer, unable to parse string as an integer'):
-        SchemaValidator({'type': 'str', 'min_length': 'xxx', 'title': 'TestModel'})
+        validate_core_schema({'type': 'str', 'min_length': 'xxx', 'title': 'TestModel'})
 
 
 def test_build_error_deep():
     with pytest.raises(SchemaError, match='Input should be a valid integer, unable to parse string as an integer'):
-        SchemaValidator(
+        validate_core_schema(
             {
                 'title': 'MyTestModel',
                 'type': 'typed-dict',
@@ -34,7 +34,7 @@ def test_schema_as_string():
 
 def test_schema_wrong_type(pydantic_version):
     with pytest.raises(SchemaError) as exc_info:
-        SchemaValidator(1)
+        validate_core_schema(1)
     assert str(exc_info.value) == (
         'Invalid Schema:\n  Input should be a valid dictionary or object to'
         ' extract fields from [type=model_attributes_type, input_value=1, input_type=int]\n'
@@ -66,7 +66,7 @@ def test_schema_definition_error():
     schema = {'type': 'union', 'choices': []}
     schema['choices'].append({'type': 'nullable', 'schema': schema})
     with pytest.raises(SchemaError, match='Recursion error - cyclic reference detected'):
-        SchemaValidator(schema)
+        validate_core_schema(schema)
 
 
 def test_not_schema_definition_error():
@@ -83,17 +83,17 @@ def test_not_schema_definition_error():
 
 def test_no_type():
     with pytest.raises(SchemaError, match="Unable to extract tag using discriminator 'type'"):
-        SchemaValidator({})
+        validate_core_schema({})
 
 
 def test_wrong_type():
     with pytest.raises(SchemaError, match="Input tag 'unknown' found using 'type' does not match any of the"):
-        SchemaValidator({'type': 'unknown'})
+        validate_core_schema({'type': 'unknown'})
 
 
 def test_function_no_mode():
     with pytest.raises(SchemaError, match="Input tag 'function' found using 'type' does not match any of the"):
-        SchemaValidator({'type': 'function'})
+        validate_core_schema({'type': 'function'})
 
 
 def test_try_self_schema_discriminator():