Add Pydantic Json field support to settings management (#6250)

changes/6250-hramezani.md

@@ -0,0 +1 @@
+Add Pydantic `Json` field support to settings management.

pydantic/env_settings.py

@@ -6,8 +6,9 @@
 from .config import BaseConfig, Extra
 from .fields import ModelField
 from .main import BaseModel
+from .types import JsonWrapper
 from .typing import StrPath, display_as_type, get_origin, is_union
-from .utils import deep_update, path_type, sequence_like
+from .utils import deep_update, lenient_issubclass, path_type, sequence_like
 
 env_file_sentinel = str(object())
 
@@ -231,6 +232,9 @@ def field_is_complex(self, field: ModelField) -> Tuple[bool, bool]:
         """
         Find out if a field is complex, and if so whether JSON errors should be ignored
         """
+        if lenient_issubclass(field.annotation, JsonWrapper):
+            return False, False
+
         if field.is_complex():
             allow_parse_failure = False
         elif is_union(get_origin(field.type_)) and field.sub_fields and any(f.is_complex() for f in field.sub_fields):

tests/test_settings.py

@@ -7,7 +7,7 @@
 
 import pytest
 
-from pydantic import BaseModel, BaseSettings, Field, HttpUrl, NoneStr, SecretStr, ValidationError, dataclasses
+from pydantic import BaseModel, BaseSettings, Field, HttpUrl, Json, NoneStr, SecretStr, ValidationError, dataclasses
 from pydantic.env_settings import (
     EnvSettingsSource,
     InitSettingsSource,
@@ -1278,3 +1278,35 @@ def parse_env_var(cls, field_name: str, raw_val: str):
 
     s = Settings()
     assert s.top == {1: 'apple', 2: 'banana'}
+
+
+def test_env_json_field(env):
+    class Settings(BaseSettings):
+        x: Json
+
+    env.set('x', '{"foo": "bar"}')
+
+    s = Settings()
+    assert s.x == {'foo': 'bar'}
+
+    env.set('x', 'test')
+    with pytest.raises(ValidationError) as exc_info:
+        Settings()
+    assert exc_info.value.errors() == [{'loc': ('x',), 'msg': 'Invalid JSON', 'type': 'value_error.json'}]
+
+
+def test_env_json_field_dict(env):
+    class Settings(BaseSettings):
+        x: Json[Dict[str, int]]
+
+    env.set('x', '{"foo": 1}')
+
+    s = Settings()
+    assert s.x == {'foo': 1}
+
+    env.set('x', '{"foo": "bar"}')
+    with pytest.raises(ValidationError) as exc_info:
+        Settings()
+    assert exc_info.value.errors() == [
+        {'loc': ('x', 'foo'), 'msg': 'value is not a valid integer', 'type': 'type_error.integer'}
+    ]