Strict types now enforce field constraints (#2617)

* Enhance strict type constraints for fields in Pydantic and Msgspec models

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Enhance strict type constraints for float fields in Pydantic models

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Refactor float value handling in base_model to improve type safety

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: koxudaxi

src/datamodel_code_generator/model/msgspec.py

@@ -301,7 +301,12 @@ def annotated(self) -> str | None:
             return None
 
         data: dict[str, Any] = {k: v for k, v in self.extras.items() if k in self._META_FIELD_KEYS}
-        if self.constraints is not None and not self.self_reference() and not self.data_type.strict:
+        has_type_constraints = self.data_type.kwargs is not None and len(self.data_type.kwargs) > 0
+        if (
+            self.constraints is not None
+            and not self.self_reference()
+            and not (self.data_type.strict and has_type_constraints)
+        ):
             data = {
                 **data,
                 **{

src/datamodel_code_generator/model/pydantic/base_model.py

@@ -107,8 +107,19 @@ def _get_strict_field_constraint_value(self, constraint: str, value: Any) -> Any
         if value is None or constraint not in self._COMPARE_EXPRESSIONS:
             return value
 
-        if any(data_type.type == "float" for data_type in self.data_type.all_data_types):
+        is_float_type = any(
+            data_type.type == "float"
+            or (data_type.strict and data_type.import_ and "Float" in data_type.import_.import_)
+            for data_type in self.data_type.all_data_types
+        )
+        if is_float_type:
+            return float(value)
+        str_value = str(value)
+        if "e" in str_value.lower():  # pragma: no cover
+            # Scientific notation like 1e-08 - keep as float
             return float(value)
+        if isinstance(value, int) and not isinstance(value, bool):  # pragma: no branch
+            return value
         return int(value)
 
     def _get_default_as_pydantic_model(self) -> str | None:
@@ -152,7 +163,12 @@ def __str__(self) -> str:  # noqa: PLR0912
         data: dict[str, Any] = {k: v for k, v in self.extras.items() if k not in self._EXCLUDE_FIELD_KEYS}
         if self.alias:
             data["alias"] = self.alias
-        if self.constraints is not None and not self.self_reference() and not self.data_type.strict:
+        has_type_constraints = self.data_type.kwargs is not None and len(self.data_type.kwargs) > 0
+        if (
+            self.constraints is not None
+            and not self.self_reference()
+            and not (self.data_type.strict and has_type_constraints)
+        ):
             data = {
                 **data,
                 **(

tests/data/expected/main/jsonschema/strict_types_all_field_constraints.py

@@ -20,12 +20,12 @@
 class User(BaseModel):
     name: Optional[StrictStr] = Field(None, example='ken')
     age: Optional[StrictInt] = None
-    salary: Optional[StrictInt] = None
-    debt: Optional[StrictInt] = None
-    loan: Optional[StrictFloat] = None
-    tel: Optional[StrictStr] = None
-    height: Optional[StrictFloat] = None
-    weight: Optional[StrictFloat] = None
-    score: Optional[StrictFloat] = None
+    salary: Optional[StrictInt] = Field(None, ge=0)
+    debt: Optional[StrictInt] = Field(None, le=0)
+    loan: Optional[StrictFloat] = Field(None, le=0.0)
+    tel: Optional[StrictStr] = Field(None, regex='^(\\([0-9]{3}\\))?[0-9]{3}-[0-9]{4}$')
+    height: Optional[StrictFloat] = Field(None, ge=0.0)
+    weight: Optional[StrictFloat] = Field(None, ge=0.0)
+    score: Optional[StrictFloat] = Field(None, ge=1e-08)
     active: Optional[StrictBool] = None
-    photo: Optional[StrictBytes] = None
+    photo: Optional[StrictBytes] = Field(None, min_length=100)

tests/data/expected/main/openapi/strict_types_field_constraints_msgspec.py

@@ -0,0 +1,18 @@
+# generated by datamodel-codegen:
+#   filename:  strict_types_field_constraints.yaml
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from typing import Annotated
+
+from msgspec import Meta
+from typing_extensions import TypeAlias
+
+Timestamp: TypeAlias = Annotated[int, Meta(ge=1, le=9999999999)]
+
+
+Score: TypeAlias = Annotated[float, Meta(ge=0.0, le=100.0)]
+
+
+Name: TypeAlias = Annotated[str, Meta(max_length=100, min_length=1)]

tests/data/expected/main/openapi/strict_types_field_constraints_pydantic_v2.py

@@ -0,0 +1,19 @@
+# generated by datamodel-codegen:
+#   filename:  strict_types_field_constraints.yaml
+#   timestamp: 2019-07-26T00:00:00+00:00
+
+from __future__ import annotations
+
+from pydantic import Field, RootModel, StrictFloat, StrictInt, StrictStr
+
+
+class Timestamp(RootModel[StrictInt]):
+    root: StrictInt = Field(..., ge=1, le=9999999999)
+
+
+class Score(RootModel[StrictFloat]):
+    root: StrictFloat = Field(..., ge=0.0, le=100.0)
+
+
+class Name(RootModel[StrictStr]):
+    root: StrictStr = Field(..., max_length=100, min_length=1)

tests/data/openapi/strict_types_field_constraints.yaml

@@ -0,0 +1,19 @@
+openapi: 3.0.0
+info:
+  title: Test API
+  version: 1.0.0
+paths: {}
+components:
+  schemas:
+    Timestamp:
+      type: integer
+      minimum: 1
+      maximum: 9999999999
+    Score:
+      type: number
+      minimum: 0.0
+      maximum: 100.0
+    Name:
+      type: string
+      minLength: 1
+      maxLength: 100

tests/main/openapi/test_main_openapi.py

@@ -3115,6 +3115,46 @@ def test_main_openapi_dot_notation_deep_inheritance(output_dir: Path) -> None:
     )
 
 
+def test_main_openapi_strict_types_field_constraints_pydantic_v2(output_file: Path) -> None:
+    """Test strict types with field constraints for pydantic v2 (issue #1884)."""
+    run_main_and_assert(
+        input_path=OPEN_API_DATA_PATH / "strict_types_field_constraints.yaml",
+        output_path=output_file,
+        input_file_type="openapi",
+        assert_func=assert_file_content,
+        expected_file="strict_types_field_constraints_pydantic_v2.py",
+        extra_args=[
+            "--output-model-type",
+            "pydantic_v2.BaseModel",
+            "--field-constraints",
+            "--strict-types",
+            "int",
+            "float",
+            "str",
+        ],
+    )
+
+
+def test_main_openapi_strict_types_field_constraints_msgspec(output_file: Path) -> None:
+    """Test strict types with field constraints for msgspec (issue #1884)."""
+    run_main_and_assert(
+        input_path=OPEN_API_DATA_PATH / "strict_types_field_constraints.yaml",
+        output_path=output_file,
+        input_file_type="openapi",
+        assert_func=assert_file_content,
+        expected_file="strict_types_field_constraints_msgspec.py",
+        extra_args=[
+            "--output-model-type",
+            "msgspec.Struct",
+            "--field-constraints",
+            "--strict-types",
+            "int",
+            "float",
+            "str",
+        ],
+    )
+
+
 def test_main_openapi_circular_imports_stripe_like(output_dir: Path) -> None:
     """Test that circular imports between root and submodules are resolved with _internal.py."""
     with freeze_time(TIMESTAMP):