Use pydantic MISSING sentinel to mark optional but non-nullable fields

pyproject.toml

@@ -16,6 +16,7 @@ dependencies = [
     "pydantic==2.14.0a1",
     "python-json-logger==4.1.0",
     "starlette==1.3.1",
+    "typing-extensions>=4.16.0",  # Transitive dependency of pydantic that we force to >=4.16.0 in order to get pickling support for the MISSING sentinel
 ]
 
 [dependency-groups]
@@ -48,7 +49,8 @@ tests = [
 typing = [
     { include-group = "build" },
     { include-group = "tests" },
-    "mypy~=2.1.0",
+    # "mypy~=2.1.0",
+    "mypy @ git+https://github.com/edgarrmondragon/mypy.git@sentinels-reloaded",
     "ty==0.0.55",
     "types-PyYAML>=6.0.12.20240808",
     "types-requests>=2.32.0",
@@ -63,6 +65,7 @@ required-version = ">=0.11"
 DEP002 = [
     "granian",  # Not imported, but used as the ASGI server as a uvicorn alternative
     "python-json-logger",  # Imported dynamically by logging configuration
+    "typing-extensions",  # Transitive dependency of pydantic that we force to >=4.16.0 in order to get pickling support for the MISSING sentinel
 ]
 
 [tool.ruff]

src/hub_api/api/api_v1/endpoints/plugins.py

@@ -7,6 +7,7 @@
 import fastapi
 import fastapi.responses
 from pydantic import BaseModel, ConfigDict, Field
+from pydantic.experimental.missing_sentinel import MISSING
 
 from hub_api import dependencies, enums, ids
 from hub_api.helpers import compatibility
@@ -89,14 +90,14 @@ class FindParams(BaseModel):
         examples=["tap-github"],
     )
 
-    type: enums.PluginTypeEnum = Field(  # type: ignore[assignment]  # ty:ignore[invalid-assignment]
-        None,
+    type: enums.PluginTypeEnum | MISSING = Field(
+        MISSING,
         description="The plugin type",
         examples=[enums.PluginTypeEnum.extractors],
     )
 
-    variant: str = Field(  # type: ignore[assignment]  # ty:ignore[invalid-assignment]
-        None,
+    variant: str | MISSING = Field(
+        MISSING,
         description="The optional variant name",
         examples=["meltanolabs"],
     )
@@ -115,7 +116,9 @@ async def find_plugin(
     hub: dependencies.Hub,
     params: Annotated[FindParams, fastapi.Query()],
 ) -> api_schemas.PluginDetails:
-    return await hub.find_plugin(plugin_name=params.name, plugin_type=params.type, variant_name=params.variant)
+    plugin_type = None if params.type is MISSING else params.type
+    variant_name = None if params.variant is MISSING else params.variant
+    return await hub.find_plugin(plugin_name=params.name, plugin_type=plugin_type, variant_name=variant_name)
 
 
 @router.get(

src/hub_api/helpers/etag.py

@@ -17,6 +17,7 @@
 from typing import TYPE_CHECKING, Annotated, override
 
 from fastapi import Header, HTTPException, Request, Response
+from pydantic.experimental.missing_sentinel import MISSING
 from starlette.middleware.base import BaseHTTPMiddleware
 
 from . import compatibility
@@ -78,7 +79,7 @@ async def dispatch(
 
 def check_etag(
     request: Request,
-    if_none_match: Annotated[str, Header(description=DESCRIPTION)] = None,  # type: ignore[assignment] # ty:ignore[invalid-parameter-default] # ruff: ignore[implicit-optional]
+    if_none_match: Annotated[str | MISSING, Header(description=DESCRIPTION)] = MISSING,
 ) -> None:
     """Get ETag value."""
     if if_none_match == _get_etag(request):

tests/app/test_app.py

@@ -89,8 +89,11 @@ async def test_plugin_search(api: httpx.AsyncClient) -> None:
                 "type": "missing",
                 "loc": ["query", "name"],
                 "msg": "Field required",
-                "input": {},
-            },
+                "input": {
+                    "type": {"_name": "MISSING", "_repr": "MISSING", "__module__": "pydantic_core"},
+                    "variant": {"_name": "MISSING", "_repr": "MISSING", "__module__": "pydantic_core"},
+                },
+            }
         ]
     }