From b7067f59a986618f91d37e53ea3cb516d5aeedc6 Mon Sep 17 00:00:00 2001
From: Saurav Venkat <sauravvenkat@Mac-56.lan>
Date: Mon, 10 Nov 2025 15:40:19 -0500
Subject: [PATCH] Removing stale code and tests for encoder

---
 fastapi/encoders.py            | 12 ++++----
 tests/test_jsonable_encoder.py | 54 +---------------------------------
 2 files changed, 6 insertions(+), 60 deletions(-)

diff --git a/fastapi/encoders.py b/fastapi/encoders.py
index 6fc6228e1..90baeb347 100644
--- a/fastapi/encoders.py
+++ b/fastapi/encoders.py
@@ -210,13 +210,11 @@ def jsonable_encoder(
     [FastAPI docs for JSON Compatible Encoder](https://fastapi.tiangolo.com/tutorial/encoder/).
     """
     custom_encoder = custom_encoder or {}
-    if custom_encoder:
-        if type(obj) in custom_encoder:
-            return custom_encoder[type(obj)](obj)
-        else:
-            for encoder_type, encoder_instance in custom_encoder.items():
-                if isinstance(obj, encoder_type):
-                    return encoder_instance(obj)
+    if type(obj) in custom_encoder:
+        return custom_encoder[type(obj)](obj)
+    for encoder_type, encoder_instance in custom_encoder.items():
+        if isinstance(obj, encoder_type):
+            return encoder_instance(obj)
     if include is not None and not isinstance(include, (set, dict)):
         include = set(include)
     if exclude is not None and not isinstance(exclude, (set, dict)):
diff --git a/tests/test_jsonable_encoder.py b/tests/test_jsonable_encoder.py
index 447c5b4d6..dc4d659b8 100644
--- a/tests/test_jsonable_encoder.py
+++ b/tests/test_jsonable_encoder.py
@@ -11,7 +11,7 @@ from fastapi._compat import PYDANTIC_V2, Undefined
 from fastapi.encoders import jsonable_encoder
 from pydantic import BaseModel, Field, ValidationError
 
-from .utils import needs_pydanticv1, needs_pydanticv2
+from .utils import needs_pydanticv2
 
 
 class Person:
@@ -149,29 +149,6 @@ def test_encode_custom_json_encoders_model_pydanticv2():
     assert jsonable_encoder(subclass_model) == {"dt_field": "2019-01-01T08:00:00+00:00"}
 
 
-# TODO: remove when deprecating Pydantic v1
-@needs_pydanticv1
-def test_encode_custom_json_encoders_model_pydanticv1():
-    class ModelWithCustomEncoder(BaseModel):
-        dt_field: datetime
-
-        class Config:
-            json_encoders = {
-                datetime: lambda dt: dt.replace(
-                    microsecond=0, tzinfo=timezone.utc
-                ).isoformat()
-            }
-
-    class ModelWithCustomEncoderSubclass(ModelWithCustomEncoder):
-        class Config:
-            pass
-
-    model = ModelWithCustomEncoder(dt_field=datetime(2019, 1, 1, 8))
-    assert jsonable_encoder(model) == {"dt_field": "2019-01-01T08:00:00+00:00"}
-    subclass_model = ModelWithCustomEncoderSubclass(dt_field=datetime(2019, 1, 1, 8))
-    assert jsonable_encoder(subclass_model) == {"dt_field": "2019-01-01T08:00:00+00:00"}
-
-
 def test_encode_model_with_config():
     model = ModelWithConfig(role=RoleEnum.admin)
     assert jsonable_encoder(model) == {"role": "admin"}
@@ -204,26 +181,6 @@ def test_encode_model_with_default():
         "bla": "bla",
     }
 
-
-@needs_pydanticv1
-def test_custom_encoders():
-    class safe_datetime(datetime):
-        pass
-
-    class MyModel(BaseModel):
-        dt_field: safe_datetime
-
-    instance = MyModel(dt_field=safe_datetime.now())
-
-    encoded_instance = jsonable_encoder(
-        instance, custom_encoder={safe_datetime: lambda o: o.strftime("%H:%M:%S")}
-    )
-    assert encoded_instance["dt_field"] == instance.dt_field.strftime("%H:%M:%S")
-
-    encoded_instance2 = jsonable_encoder(instance)
-    assert encoded_instance2["dt_field"] == instance.dt_field.isoformat()
-
-
 def test_custom_enum_encoders():
     def custom_enum_encoder(v: Enum):
         return v.value.lower()
@@ -285,15 +242,6 @@ def test_encode_model_with_pure_windows_path():
     assert jsonable_encoder(obj) == {"path": "\\foo\\bar"}
 
 
-@needs_pydanticv1
-def test_encode_root():
-    class ModelWithRoot(BaseModel):
-        __root__: str
-
-    model = ModelWithRoot(__root__="Foo")
-    assert jsonable_encoder(model) == "Foo"
-
-
 @needs_pydanticv2
 def test_decimal_encoder_float():
     data = {"value": Decimal(1.23)}