feat(entities): don't control uniqueness

Author: emptybutton

src/app_name_snake_case/application/register_user.py

@@ -13,7 +13,6 @@
 from app_name_snake_case.application.ports.user_views import UserViews
 from app_name_snake_case.application.ports.users import Users
 from app_name_snake_case.entities.core.user import (
-    RegisteredUserForRegisteredUserError,
     registered_user_when,
 )
 
@@ -24,12 +23,14 @@ class Output[SignedUserIDT, UserViewT]:
     user_view: UserViewT
 
 
+class RegisteredUserToRegisterUserError(Exception): ...
+
+
+class TakenUserNameToRegisterUserError(Exception): ...
+
+
 @dataclass(kw_only=True, frozen=True, slots=True)
 class RegisterUser[SignedUserIDT, UserViewT, UserViewWithIDT]:
-    """
-    :raises app_name_snake_case.entities.user.RegisteredUserForRegisteredUserError:
-    """  # noqa: E501
-
     user_id_signing: UserIDSigning[SignedUserIDT]
     users: Users
     map: Map
@@ -39,27 +40,26 @@ class RegisterUser[SignedUserIDT, UserViewT, UserViewWithIDT]:
     async def __call__(
         self, signed_user_id: SignedUserIDT | None, user_name: str
     ) -> Output[SignedUserIDT, UserViewT]:
-        if signed_user_id is None:
-            user_id = None
-        else:
+        """
+        :raises app_name_snake_case.application.register_user.RegisteredUserToRegisterUserError:
+        :raises app_name_snake_case.application.register_user.TakenUserNameToRegisterUserError:
+        """  # noqa: E501
+
+        if signed_user_id is not None:
             user_id = await self.user_id_signing.user_id_when(
                 signed_user_id=signed_user_id
             )
 
-        async with self.transaction:
-            if user_id is None:
-                user = None
-            else:
-                user = await self.users.user_with_id(user_id)
+            if user_id is not None:
+                raise RegisteredUserToRegisterUserError
 
-            registered_user = registered_user_when(
-                user=user, user_name=user_name
-            )
+        registered_user = registered_user_when(user_name=user_name)
 
+        async with self.transaction:
             try:
                 await self.map(registered_user)
             except NotUniqueUserNameError as error:
-                raise RegisteredUserForRegisteredUserError from error
+                raise TakenUserNameToRegisterUserError from error
 
             view = await self.user_views.view_of_user(just(registered_user))
 

src/app_name_snake_case/entities/core/user.py

@@ -1,5 +1,4 @@
 from dataclasses import dataclass
-from typing import TypeGuard
 from uuid import UUID, uuid4
 
 from effect import IdentifiedValue, New, new
@@ -10,27 +9,5 @@ class User(IdentifiedValue[UUID]):
     name: str
 
 
-type RegisteredUser = User
-type UnregisteredUser = None
-type AnyUser = RegisteredUser | UnregisteredUser
-
-
-unregistered_user: UnregisteredUser = None
-
-
-def is_registered(user: AnyUser) -> TypeGuard[RegisteredUser]:
-    return user is not None
-
-
-class RegisteredUserForRegisteredUserError(Exception): ...
-
-
-def registered_user_when(*, user: AnyUser, user_name: str) -> New[User]:
-    """
-    :raises app_name_snake_case.entities.user.RegisteredUserForRegisteredUserError:
-    """  # noqa: E501
-
-    if is_registered(user):
-        raise RegisteredUserForRegisteredUserError
-
+def registered_user_when(*, user_name: str) -> New[User]:
     return new(User(id=uuid4(), name=user_name))

src/app_name_snake_case/infrastructure/adapters/map.py

@@ -36,12 +36,13 @@ async def __call__(
             await self.session.flush()
         except IntegrityError as error:
             self._handle_integrity_error(error)
-            raise error from error
 
     def _handle_integrity_error(self, error: IntegrityError) -> None:
-        if isinstance(error.orig, UniqueViolation):
-            table_name = error.orig.diag.table_name
-            column_name = error.orig.diag.column_name
-
-            if table_name == "user_table" and column_name == "name":
-                raise NotUniqueUserNameError from error
+        match error.orig:
+            case UniqueViolation() as unique_error:
+                constraint_name = unique_error.diag.constraint_name
+
+                if constraint_name == "users_name_unique":
+                    raise NotUniqueUserNameError from error
+            case _:
+                raise error from error

…/versions/62dcf52bf2a4_add_user_table.py …/versions/e78dd190868f_add_user_table.pysrc/app_name_snake_case/infrastructure/alembic/versions/62dcf52bf2a4_add_user_table.py renamed to src/app_name_snake_case/infrastructure/alembic/versions/e78dd190868f_add_user_table.py src/app_name_snake_case/infrastructure/alembic/versions/62dcf52bf2a4_add_user_table.py renamed to src/app_name_snake_case/infrastructure/alembic/versions/e78dd190868f_add_user_table.py

@@ -1,30 +1,30 @@
 """add user table
 
-Revision ID: 62dcf52bf2a4
+Revision ID: e78dd190868f
 Revises:
-Create Date: 2025-03-03 11:02:01.231021
+Create Date: 2025-03-30 13:37:27.048793
 
 """
-
 from collections.abc import Sequence
 
 import sqlalchemy as sa
 from alembic import op
 
 
-revision: str = "62dcf52bf2a4"
+revision: str = "e78dd190868f"
 down_revision: str | None = None
 branch_labels: str | Sequence[str] | None = None
 depends_on: str | Sequence[str] | None = None
 
 
 def upgrade() -> None:
     # ### commands auto generated by Alembic - please adjust! ###
-    op.create_table(
-        "users",
-        sa.Column("id", sa.Uuid(), nullable=False),
-        sa.Column("name", sa.VARCHAR(), nullable=False),
-        sa.PrimaryKeyConstraint("id"),
+    op.create_table("users",
+    sa.Column("id", sa.Uuid(), nullable=False),
+    sa.Column("name", sa.String(), nullable=False),
+    sa.PrimaryKeyConstraint("id"),
+    sa.UniqueConstraint("name"),
+    sa.UniqueConstraint("name", name="users_name_unique")
     )
     # ### end Alembic commands ###
 

src/app_name_snake_case/infrastructure/sqlalchemy/tables.py

@@ -1,4 +1,11 @@
-from sqlalchemy import Column, MetaData, String, Table, Uuid
+from sqlalchemy import (
+    Column,
+    MetaData,
+    String,
+    Table,
+    UniqueConstraint,
+    Uuid,
+)
 
 
 metadata = MetaData()
@@ -8,4 +15,5 @@
     metadata,
     Column("id", Uuid(), primary_key=True, nullable=False),
     Column("name", String(), nullable=False, unique=True),
+    UniqueConstraint("name", name="users_name_unique"),
 )

src/app_name_snake_case/presentation/fastapi/routes/register_user.py

@@ -3,9 +3,10 @@
 from fastapi.responses import JSONResponse, Response
 from pydantic import BaseModel, Field
 
-from app_name_snake_case.application.register_user import RegisterUser
-from app_name_snake_case.entities.core.user import (
-    RegisteredUserForRegisteredUserError,
+from app_name_snake_case.application.register_user import (
+    RegisteredUserToRegisterUserError,
+    RegisterUser,
+    TakenUserNameToRegisterUserError,
 )
 from app_name_snake_case.presentation.fastapi.cookies import (
     UserIDCookie,
@@ -16,6 +17,7 @@
 )
 from app_name_snake_case.presentation.fastapi.schemas.output import (
     AlreadyRegisteredUserSchema,
+    AlreadyTakenUserNameSchema,
     UserSchema,
 )
 from app_name_snake_case.presentation.fastapi.tags import Tag
@@ -33,7 +35,10 @@ class RegisterUserSchema(BaseModel):
     responses={
         status.HTTP_201_CREATED: {"model": NoDataSchema},
         status.HTTP_409_CONFLICT: {
-            "model": ErrorListSchema[AlreadyRegisteredUserSchema]
+            "model": (
+                ErrorListSchema[AlreadyRegisteredUserSchema]
+                | ErrorListSchema[AlreadyTakenUserNameSchema]
+            )
         },
     },
     summary="Register user",
@@ -50,9 +55,19 @@ async def register_user_route(
         result = await register_user(
             signed_user_id=signed_user_id, user_name=request_body.user_name
         )
-    except RegisteredUserForRegisteredUserError:
-        response_body_model = AlreadyRegisteredUserSchema().to_list()
-        response_body = response_body_model.model_dump(by_alias=True)
+    except RegisteredUserToRegisterUserError:
+        response_body = (
+            AlreadyRegisteredUserSchema()
+            .to_list()
+            .model_dump(mode="json", by_alias=True)
+        )
+        return JSONResponse(response_body, status_code=status.HTTP_409_CONFLICT)
+    except TakenUserNameToRegisterUserError:
+        response_body = (
+            AlreadyTakenUserNameSchema()
+            .to_list()
+            .model_dump(mode="json", by_alias=True)
+        )
         return JSONResponse(response_body, status_code=status.HTTP_409_CONFLICT)
 
     response_body = result.user_view.model_dump(mode="json", by_alias=True)

src/app_name_snake_case/presentation/fastapi/schemas/output.py

@@ -11,3 +11,7 @@ class UserSchema(BaseModel):
 
 class AlreadyRegisteredUserSchema(ErrorSchema):
     type: Literal["alreadyRegisteredUser"] = "alreadyRegisteredUser"
+
+
+class AlreadyTakenUserNameSchema(ErrorSchema):
+    type: Literal["alreadyTakenUserName"] = "alreadyTakenUserName"