feat: replace python-dateutil with stdlib datetime.fromisoformat

Drop the python-dateutil dependency from both the generator and all
generated client code. Date/datetime parsing now uses the stdlib:

- datetime fields: datetime.datetime.fromisoformat(v.replace("Z", "+00:00"))
- date fields: datetime.date.fromisoformat(v)

The .replace("Z", "+00:00") call is needed because Python 3.10's
fromisoformat() does not accept the Z timezone suffix (added in 3.11).
It is a no-op on strings that do not contain Z.

Default values in OpenAPI specs are normalized at generation time
(Z replaced with +00:00), so the generated default expressions are
clean datetime.datetime.fromisoformat("...") calls without the
replace.

This removes one runtime dependency from every generated client
package, reducing install size and eliminating a dependency that is
in maintenance-only mode upstream.

Author: splch

end_to_end_tests/docstrings-on-attributes-golden-record/pyproject.toml

@@ -13,7 +13,6 @@ include = ["my_test_api_client/py.typed"]
 python = "^3.10"
 httpx = ">=0.23.0,<0.29.0"
 attrs = ">=22.2.0"
-python-dateutil = "^2.8.0"
 
 [build-system]
 requires = ["poetry-core>=2.0.0,<3.0.0"]

end_to_end_tests/golden-record/my_test_api_client/api/default/get_common_parameters.py

@@ -12,7 +12,6 @@ def _get_kwargs(
     *,
     common: str | Unset = UNSET,
 ) -> dict[str, Any]:
-
     params: dict[str, Any] = {}
 
     params["common"] = common

end_to_end_tests/golden-record/my_test_api_client/api/default/get_models_allof.py

@@ -10,7 +10,6 @@
 
 
 def _get_kwargs() -> dict[str, Any]:
-
     _kwargs: dict[str, Any] = {
         "method": "get",
         "url": "/models/allof",

end_to_end_tests/golden-record/my_test_api_client/api/default/get_models_oneof_with_required_const.py

@@ -15,7 +15,6 @@
 
 
 def _get_kwargs() -> dict[str, Any]:
-
     _kwargs: dict[str, Any] = {
         "method": "get",
         "url": "/models/oneof-with-required-const",

end_to_end_tests/golden-record/my_test_api_client/api/default/post_common_parameters.py

@@ -12,7 +12,6 @@ def _get_kwargs(
     *,
     common: str | Unset = UNSET,
 ) -> dict[str, Any]:
-
     params: dict[str, Any] = {}
 
     params["common"] = common

end_to_end_tests/golden-record/my_test_api_client/api/default/reserved_parameters.py

@@ -13,7 +13,6 @@ def _get_kwargs(
     client_query: str,
     url_query: str,
 ) -> dict[str, Any]:
-
     params: dict[str, Any] = {}
 
     params["client"] = client_query

end_to_end_tests/golden-record/my_test_api_client/api/defaults/defaults_tests_defaults_post.py

@@ -3,7 +3,6 @@
 from typing import Any
 
 import httpx
-from dateutil.parser import isoparse
 
 from ... import errors
 from ...client import AuthenticatedClient, Client
@@ -17,7 +16,7 @@ def _get_kwargs(
     *,
     string_prop: str = "the default string",
     string_with_num: str = "1",
-    date_prop: datetime.date = isoparse("1010-10-10").date(),
+    date_prop: datetime.date = datetime.date.fromisoformat("1010-10-10"),
     float_prop: float = 3.14,
     float_with_int: float = 3.0,
     int_prop: int = 7,
@@ -29,7 +28,6 @@ def _get_kwargs(
     model_prop: ModelWithUnionProperty,
     required_model_prop: ModelWithUnionProperty,
 ) -> dict[str, Any]:
-
     params: dict[str, Any] = {}
 
     params["string_prop"] = string_prop
@@ -121,7 +119,7 @@ def sync_detailed(
     client: AuthenticatedClient | Client,
     string_prop: str = "the default string",
     string_with_num: str = "1",
-    date_prop: datetime.date = isoparse("1010-10-10").date(),
+    date_prop: datetime.date = datetime.date.fromisoformat("1010-10-10"),
     float_prop: float = 3.14,
     float_with_int: float = 3.0,
     int_prop: int = 7,
@@ -138,7 +136,7 @@ def sync_detailed(
     Args:
         string_prop (str):  Default: 'the default string'.
         string_with_num (str):  Default: '1'.
-        date_prop (datetime.date):  Default: isoparse('1010-10-10').date().
+        date_prop (datetime.date):  Default: datetime.date.fromisoformat('1010-10-10').
         float_prop (float):  Default: 3.14.
         float_with_int (float):  Default: 3.0.
         int_prop (int):  Default: 7.
@@ -186,7 +184,7 @@ def sync(
     client: AuthenticatedClient | Client,
     string_prop: str = "the default string",
     string_with_num: str = "1",
-    date_prop: datetime.date = isoparse("1010-10-10").date(),
+    date_prop: datetime.date = datetime.date.fromisoformat("1010-10-10"),
     float_prop: float = 3.14,
     float_with_int: float = 3.0,
     int_prop: int = 7,
@@ -203,7 +201,7 @@ def sync(
     Args:
         string_prop (str):  Default: 'the default string'.
         string_with_num (str):  Default: '1'.
-        date_prop (datetime.date):  Default: isoparse('1010-10-10').date().
+        date_prop (datetime.date):  Default: datetime.date.fromisoformat('1010-10-10').
         float_prop (float):  Default: 3.14.
         float_with_int (float):  Default: 3.0.
         int_prop (int):  Default: 7.
@@ -246,7 +244,7 @@ async def asyncio_detailed(
     client: AuthenticatedClient | Client,
     string_prop: str = "the default string",
     string_with_num: str = "1",
-    date_prop: datetime.date = isoparse("1010-10-10").date(),
+    date_prop: datetime.date = datetime.date.fromisoformat("1010-10-10"),
     float_prop: float = 3.14,
     float_with_int: float = 3.0,
     int_prop: int = 7,
@@ -263,7 +261,7 @@ async def asyncio_detailed(
     Args:
         string_prop (str):  Default: 'the default string'.
         string_with_num (str):  Default: '1'.
-        date_prop (datetime.date):  Default: isoparse('1010-10-10').date().
+        date_prop (datetime.date):  Default: datetime.date.fromisoformat('1010-10-10').
         float_prop (float):  Default: 3.14.
         float_with_int (float):  Default: 3.0.
         int_prop (int):  Default: 7.
@@ -309,7 +307,7 @@ async def asyncio(
     client: AuthenticatedClient | Client,
     string_prop: str = "the default string",
     string_with_num: str = "1",
-    date_prop: datetime.date = isoparse("1010-10-10").date(),
+    date_prop: datetime.date = datetime.date.fromisoformat("1010-10-10"),
     float_prop: float = 3.14,
     float_with_int: float = 3.0,
     int_prop: int = 7,
@@ -326,7 +324,7 @@ async def asyncio(
     Args:
         string_prop (str):  Default: 'the default string'.
         string_with_num (str):  Default: '1'.
-        date_prop (datetime.date):  Default: isoparse('1010-10-10').date().
+        date_prop (datetime.date):  Default: datetime.date.fromisoformat('1010-10-10').
         float_prop (float):  Default: 3.14.
         float_with_int (float):  Default: 3.0.
         int_prop (int):  Default: 7.

end_to_end_tests/golden-record/my_test_api_client/api/enums/bool_enum_tests_bool_enum_post.py

@@ -12,7 +12,6 @@ def _get_kwargs(
     *,
     bool_enum: bool,
 ) -> dict[str, Any]:
-
     params: dict[str, Any] = {}
 
     params["bool_enum"] = bool_enum

end_to_end_tests/golden-record/my_test_api_client/api/enums/int_enum_tests_int_enum_post.py

@@ -13,7 +13,6 @@ def _get_kwargs(
     *,
     int_enum: AnIntEnum,
 ) -> dict[str, Any]:
-
     params: dict[str, Any] = {}
 
     json_int_enum = int_enum.value

end_to_end_tests/golden-record/my_test_api_client/api/location/get_location_query_optionality.py

@@ -16,7 +16,6 @@ def _get_kwargs(
     null_not_required: datetime.datetime | None | Unset = UNSET,
     not_null_not_required: datetime.datetime | Unset = UNSET,
 ) -> dict[str, Any]:
-
     params: dict[str, Any] = {}
 
     json_not_null_required = not_null_required.isoformat()