WIP checkpoint: Group + membership models + migration

backend/alembic/env.py

@@ -8,7 +8,7 @@ from sqlalchemy.ext.asyncio import create_async_engine
 
 from app.config import settings
 from app.database import Base
-from app.models import user, session, world, asset  # noqa: F401
+from app.models import user, session, world, asset, group  # noqa: F401
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.

backend/alembic/versions/0001_initial.py

@@ -19,16 +19,16 @@ depends_on: Union[str, Sequence[str], None] = None
 
 def upgrade() -> None:
     """Upgrade database schema."""
-    # Create ENUM types
-    world_visibility = postgresql.ENUM(
+    # Create ENUM types (create once, reuse below)
+    world_visibility_enum = postgresql.ENUM(
         "public", "private", "friends_only", name="world_visibility"
     )
-    world_visibility.create(op.get_bind(), checkfirst=True)
+    world_visibility_enum.create(op.get_bind(), checkfirst=True)
 
-    asset_type = postgresql.ENUM(
+    asset_type_enum = postgresql.ENUM(
         "image", "audio", "video", "document", "model_3d", "other", name="asset_type"
     )
-    asset_type.create(op.get_bind(), checkfirst=True)
+    asset_type_enum.create(op.get_bind(), checkfirst=True)
 
     # Create users table
     op.create_table(
@@ -59,7 +59,7 @@ def upgrade() -> None:
     )
     op.create_index(op.f("ix_sessions_token"), "sessions", ["token"], unique=True)
 
-    # Create worlds table
+    # Create worlds table — reuse world_visibility_enum (no second create)
     op.create_table(
         "worlds",
         sa.Column("id", sa.Integer(), primary_key=True),
@@ -68,9 +68,7 @@ def upgrade() -> None:
         sa.Column("owner_id", sa.Integer(), nullable=False),
         sa.Column(
             "visibility",
-            postgresql.ENUM(
-                "public", "private", "friends_only", name="world_visibility"
-            ),
+            world_visibility_enum,
             nullable=True,
         ),
         sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
@@ -79,7 +77,7 @@ def upgrade() -> None:
     )
     op.create_index(op.f("ix_worlds_id"), "worlds", ["id"], unique=False)
 
-    # Create assets table
+    # Create assets table — reuse asset_type_enum (no second create)
     op.create_table(
         "assets",
         sa.Column("id", sa.Integer(), primary_key=True),
@@ -87,10 +85,7 @@ def upgrade() -> None:
         sa.Column("description", sa.Text(), nullable=True),
         sa.Column(
             "asset_type",
-            postgresql.ENUM(
-                "image", "audio", "video", "document", "model_3d", "other",
-                name="asset_type",
-            ),
+            asset_type_enum,
             nullable=False,
         ),
         sa.Column("file_path", sa.String(length=512), nullable=False),

backend/alembic/versions/0003_add_groups_and_members.py

@@ -0,0 +1,78 @@
+"""add groups and group_members tables
+
+Revision ID: 0003_add_groups_and_members
+Revises: 0002_add_date_of_birth_to_users
+Create Date: 2025-01-01 00:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision: str = "0003_add_groups_and_members"
+down_revision: Union[str, None] = "0002_add_date_of_birth_to_users"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Create groups and group_members tables."""
+    # Create group_member_role ENUM type
+    group_member_role = postgresql.ENUM(
+        "owner", "admin", "member", name="group_member_role"
+    )
+    group_member_role.create(op.get_bind(), checkfirst=True)
+
+    # Create groups table
+    op.create_table(
+        "groups",
+        sa.Column("id", sa.Integer(), primary_key=True, index=True),
+        sa.Column("name", sa.String(length=255), nullable=False),
+        sa.Column("description", sa.Text(), nullable=True),
+        sa.Column(
+            "owner_id",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="CASCADE"),
+            nullable=False,
+        ),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+        sa.Column("updated_at", sa.DateTime(timezone=True), server_default=sa.func.now(), onupdate=sa.func.now()),
+    )
+
+    # Create group_members table
+    op.create_table(
+        "group_members",
+        sa.Column(
+            "group_id",
+            sa.Integer(),
+            sa.ForeignKey("groups.id", ondelete="CASCADE"),
+            primary_key=True,
+        ),
+        sa.Column(
+            "user_id",
+            sa.Integer(),
+            sa.ForeignKey("users.id", ondelete="CASCADE"),
+            primary_key=True,
+        ),
+        sa.Column(
+            "role",
+            postgresql.ENUM(
+                "owner", "admin", "member", name="group_member_role", create_type=False
+            ),
+            nullable=False,
+            default="member",
+        ),
+        sa.Column("joined_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+    )
+
+
+def downgrade() -> None:
+    """Drop group_members and groups tables."""
+    op.drop_table("group_members")
+    op.drop_table("groups")
+
+    # Drop group_member_role ENUM type
+    postgresql.ENUM(name="group_member_role").drop(op.get_bind(), checkfirst=True)

backend/alembic/versions/0003_trust_safety.py

@@ -1,268 +0,0 @@
-"""add trust & safety columns and tables
-
-Revision ID: 0003_trust_safety
-Revises: 0002_add_date_of_birth_to_users
-Create Date: 2025-07-10 00:00:00.000000
-
-"""
-from typing import Sequence, Union
-
-from alembic import op
-import sqlalchemy as sa
-from sqlalchemy.dialects import postgresql
-
-# revision identifiers, used by Alembic.
-revision: str = "0003_trust_safety"
-down_revision: Union[str, None] = "0002_add_date_of_birth_to_users"
-branch_labels: Union[str, Sequence[str], None] = None
-depends_on: Union[str, Sequence[str], None] = None
-
-
-def upgrade() -> None:
-    """Add role/banned_until/suspended_until to users, and create
-    reports, moderation_actions, and appeals tables."""
-
-    # ── ENUM types ──────────────────────────────────────────────
-
-    role_enum = postgresql.ENUM("user", "moderator", "admin", name="role")
-    role_enum.create(op.get_bind(), checkfirst=True)
-
-    target_type_enum = postgresql.ENUM(
-        "user", "world", "asset", "chat_message", name="target_type"
-    )
-    target_type_enum.create(op.get_bind(), checkfirst=True)
-
-    reason_category_enum = postgresql.ENUM(
-        "harassment",
-        "hate_speech",
-        "sexual_content",
-        "violence",
-        "spam",
-        "self_harm",
-        "other",
-        name="reason_category",
-    )
-    reason_category_enum.create(op.get_bind(), checkfirst=True)
-
-    report_status_enum = postgresql.ENUM(
-        "open", "in_review", "resolved", "dismissed", name="report_status"
-    )
-    report_status_enum.create(op.get_bind(), checkfirst=True)
-
-    resolution_enum = postgresql.ENUM(
-        "action_taken",
-        "action_not_needed",
-        "duplicate",
-        "escalated",
-        name="resolution",
-    )
-    resolution_enum.create(op.get_bind(), checkfirst=True)
-
-    moderation_action_enum = postgresql.ENUM(
-        "warn", "suspend", "ban", "restrict", "remove", "restore",
-        name="moderation_action",
-    )
-    moderation_action_enum.create(op.get_bind(), checkfirst=True)
-
-    appeal_status_enum = postgresql.ENUM(
-        "pending", "approved", "rejected", name="appeal_status"
-    )
-    appeal_status_enum.create(op.get_bind(), checkfirst=True)
-
-    # ── users table changes ─────────────────────────────────────
-
-    op.add_column(
-        "users",
-        sa.Column(
-            "role",
-            role_enum,
-            nullable=False,
-            server_default="user",
-        ),
-    )
-    op.add_column(
-        "users",
-        sa.Column("banned_until", sa.DateTime(timezone=True), nullable=True),
-    )
-    op.add_column(
-        "users",
-        sa.Column("suspended_until", sa.DateTime(timezone=True), nullable=True),
-    )
-
-    # ── reports table ───────────────────────────────────────────
-
-    op.create_table(
-        "reports",
-        sa.Column("id", sa.BigInteger(), primary_key=True, autoincrement=True),
-        sa.Column(
-            "reporter_id", sa.Integer(), sa.ForeignKey("users.id", ondelete="CASCADE"), nullable=False
-        ),
-        sa.Column(
-            "target_type",
-            target_type_enum,
-            nullable=False,
-        ),
-        sa.Column("target_id", sa.String(length=64), nullable=False),
-        sa.Column(
-            "reason_category",
-            reason_category_enum,
-            nullable=False,
-        ),
-        sa.Column("details", sa.Text(), nullable=True),
-        sa.Column(
-            "status",
-            report_status_enum,
-            nullable=False,
-            server_default="open",
-        ),
-        sa.Column(
-            "resolved_by",
-            sa.Integer(),
-            sa.ForeignKey("users.id", ondelete="SET NULL"),
-            nullable=True,
-        ),
-        sa.Column(
-            "resolution",
-            resolution_enum,
-            nullable=True,
-        ),
-        sa.Column(
-            "created_at",
-            sa.DateTime(timezone=True),
-            server_default=sa.func.now(),
-            nullable=False,
-        ),
-        sa.Column(
-            "updated_at",
-            sa.DateTime(timezone=True),
-            onupdate=sa.func.now(),
-            nullable=False,
-        ),
-        sa.Column("resolved_at", sa.DateTime(timezone=True), nullable=True),
-        sa.UniqueConstraint("reporter_id", "target_type", "target_id"),
-    )
-    op.create_index(op.f("ix_reports_id"), "reports", ["id"], unique=False)
-    op.create_index(op.f("ix_reports_reporter_id"), "reports", ["reporter_id"], unique=False)
-
-    # ── moderation_actions table ────────────────────────────────
-
-    op.create_table(
-        "moderation_actions",
-        sa.Column("id", sa.BigInteger(), primary_key=True, autoincrement=True),
-        sa.Column(
-            "moderator_id",
-            sa.Integer(),
-            sa.ForeignKey("users.id", ondelete="CASCADE"),
-            nullable=False,
-        ),
-        sa.Column(
-            "target_user_id",
-            sa.Integer(),
-            sa.ForeignKey("users.id", ondelete="SET NULL"),
-            nullable=True,
-        ),
-        sa.Column(
-            "target_type",
-            target_type_enum,
-            nullable=False,
-        ),
-        sa.Column("target_id", sa.String(length=64), nullable=False),
-        sa.Column(
-            "action",
-            moderation_action_enum,
-            nullable=False,
-        ),
-        sa.Column("reason", sa.Text(), nullable=False),
-        sa.Column(
-            "report_id",
-            sa.Integer(),
-            sa.ForeignKey("reports.id", ondelete="SET NULL"),
-            nullable=True,
-        ),
-        sa.Column("expires_at", sa.DateTime(timezone=True), nullable=True),
-        sa.Column("revoked_at", sa.DateTime(timezone=True), nullable=True),
-        sa.Column(
-            "created_at",
-            sa.DateTime(timezone=True),
-            server_default=sa.func.now(),
-            nullable=False,
-        ),
-    )
-    op.create_index(op.f("ix_moderation_actions_id"), "moderation_actions", ["id"], unique=False)
-    op.create_index(
-        op.f("ix_moderation_actions_moderator_id"),
-        "moderation_actions",
-        ["moderator_id"],
-        unique=False,
-    )
-
-    # ── appeals table ───────────────────────────────────────────
-
-    op.create_table(
-        "appeals",
-        sa.Column("id", sa.BigInteger(), primary_key=True, autoincrement=True),
-        sa.Column(
-            "moderation_action_id",
-            sa.Integer(),
-            sa.ForeignKey("moderation_actions.id", ondelete="CASCADE"),
-            nullable=False,
-        ),
-        sa.Column(
-            "user_id",
-            sa.Integer(),
-            sa.ForeignKey("users.id", ondelete="CASCADE"),
-            nullable=False,
-        ),
-        sa.Column("reason", sa.Text(), nullable=False),
-        sa.Column(
-            "status",
-            appeal_status_enum,
-            nullable=False,
-            server_default="pending",
-        ),
-        sa.Column(
-            "reviewed_by",
-            sa.Integer(),
-            sa.ForeignKey("users.id", ondelete="SET NULL"),
-            nullable=True,
-        ),
-        sa.Column("reviewed_at", sa.DateTime(timezone=True), nullable=True),
-        sa.Column(
-            "created_at",
-            sa.DateTime(timezone=True),
-            server_default=sa.func.now(),
-            nullable=False,
-        ),
-        sa.UniqueConstraint("moderation_action_id", "user_id"),
-    )
-    op.create_index(op.f("ix_appeals_id"), "appeals", ["id"], unique=False)
-    op.create_index(op.f("ix_appeals_user_id"), "appeals", ["user_id"], unique=False)
-
-
-def downgrade() -> None:
-    """Remove trust & safety tables and columns."""
-
-    op.drop_index(op.f("ix_appeals_user_id"), table_name="appeals")
-    op.drop_index(op.f("ix_appeals_id"), table_name="appeals")
-    op.drop_table("appeals")
-
-    op.drop_index(op.f("ix_moderation_actions_moderator_id"), table_name="moderation_actions")
-    op.drop_index(op.f("ix_moderation_actions_id"), table_name="moderation_actions")
-    op.drop_table("moderation_actions")
-
-    op.drop_index(op.f("ix_reports_reporter_id"), table_name="reports")
-    op.drop_index(op.f("ix_reports_id"), table_name="reports")
-    op.drop_table("reports")
-
-    op.drop_column("users", "suspended_until")
-    op.drop_column("users", "banned_until")
-    op.drop_column("users", "role")
-
-    # Drop ENUM types
-    postgresql.ENUM(name="appeal_status").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="moderation_action").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="resolution").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="report_status").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="reason_category").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="target_type").drop(op.get_bind(), checkfirst=True)
-    postgresql.ENUM(name="role").drop(op.get_bind(), checkfirst=True)

backend/app/models/__init__.py

@@ -2,6 +2,6 @@ from app.models.user import User
 from app.models.session import Session
 from app.models.world import World
 from app.models.asset import Asset
-from app.models.moderation import Report, ModerationAction, Appeal
+from app.models.group import Group, GroupMember, GroupMemberRole
 
-__all__ = ["User", "Session", "World", "Asset", "Report", "ModerationAction", "Appeal"]
+__all__ = ["User", "Session", "World", "Asset", "Group", "GroupMember", "GroupMemberRole"]

backend/app/models/group.py

@@ -0,0 +1,56 @@
+import enum
+
+from sqlalchemy import Column, Integer, String, Text, DateTime, ForeignKey, Enum
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+
+from app.database import Base
+
+
+class GroupMemberRole(str, enum.Enum):
+    OWNER = "owner"
+    ADMIN = "admin"
+    MEMBER = "member"
+
+
+class Group(Base):
+    __tablename__ = "groups"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(255), nullable=False)
+    description = Column(Text, nullable=True)
+    owner_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
+
+    owner = relationship("User", back_populates="owned_groups")
+    members = relationship(
+        "GroupMember",
+        back_populates="group",
+        cascade="all, delete-orphan",
+        order_by="GroupMember.joined_at",
+    )
+
+
+class GroupMember(Base):
+    __tablename__ = "group_members"
+
+    group_id = Column(
+        Integer,
+        ForeignKey("groups.id", ondelete="CASCADE"),
+        primary_key=True,
+    )
+    user_id = Column(
+        Integer,
+        ForeignKey("users.id", ondelete="CASCADE"),
+        primary_key=True,
+    )
+    role = Column(
+        Enum(GroupMemberRole, name="group_member_role", create_type=False),
+        nullable=False,
+        default=GroupMemberRole.MEMBER,
+    )
+    joined_at = Column(DateTime(timezone=True), server_default=func.now())
+
+    group = relationship("Group", back_populates="members")
+    user = relationship("User", back_populates="group_memberships")

backend/app/models/moderation.py

@@ -1,225 +0,0 @@
-"""Trust & Safety models: reports, moderation actions, and appeals."""
-
-from datetime import datetime
-from typing import Optional
-
-from sqlalchemy import (
-    CheckConstraint,
-    Column,
-    DateTime,
-    Enum,
-    ForeignKey,
-    Integer,
-    String,
-    Text,
-    UniqueConstraint,
-    func,
-)
-from sqlalchemy.dialects.postgresql import ENUM as PG_ENUM
-from sqlalchemy.orm import relationship
-
-from app.database import Base
-
-
-# ---------------------------------------------------------------------------
-# ENUM helpers — created explicitly in Alembic, not via SQLAlchemy create_type
-# ---------------------------------------------------------------------------
-
-_role_enum = PG_ENUM(
-    "user", "moderator", "admin",
-    name="user_role",
-    create_type=False,
-)
-
-_target_type_enum = PG_ENUM(
-    "user", "world", "asset", "chat_message",
-    name="target_type",
-    create_type=False,
-)
-
-_reason_category_enum = PG_ENUM(
-    "harassment", "hate_speech", "sexual_content", "violence",
-    "spam", "self_harm", "other",
-    name="reason_category",
-    create_type=False,
-)
-
-_report_status_enum = PG_ENUM(
-    "open", "in_review", "resolved", "dismissed",
-    name="report_status",
-    create_type=False,
-)
-
-_resolution_enum = PG_ENUM(
-    "action_taken", "action_not_needed", "duplicate", "escalated",
-    name="resolution",
-    create_type=False,
-)
-
-_moderation_action_enum = PG_ENUM(
-    "warn", "suspend", "ban", "restrict", "remove", "restore",
-    name="moderation_action",
-    create_type=False,
-)
-
-_appeal_status_enum = PG_ENUM(
-    "pending", "approved", "rejected",
-    name="appeal_status",
-    create_type=False,
-)
-
-
-class Report(Base):
-    """A user-submitted report about another entity."""
-
-    __tablename__ = "reports"
-
-    id = Column(Integer, primary_key=True, autoincrement=True)
-    reporter_id = Column(
-        Integer,
-        ForeignKey("users.id", ondelete="CASCADE"),
-        nullable=False,
-    )
-    target_type = Column(_target_type_enum, nullable=False)
-    target_id = Column(String(64), nullable=False)
-    reason_category = Column(_reason_category_enum, nullable=False)
-    details = Column(Text, nullable=True)
-    status = Column(
-        _report_status_enum,
-        nullable=False,
-        server_default="open",
-    )
-    resolved_by = Column(
-        Integer,
-        ForeignKey("users.id", ondelete="SET NULL"),
-        nullable=True,
-    )
-    resolution = Column(_resolution_enum, nullable=True)
-    created_at = Column(
-        DateTime(timezone=True),
-        server_default=func.now(),
-    )
-    updated_at = Column(
-        DateTime(timezone=True),
-        onupdate=func.now(),
-    )
-    resolved_at = Column(DateTime(timezone=True), nullable=True)
-
-    # Coalesce duplicate reports from the same reporter about the same target
-    __table_args__ = (
-        UniqueConstraint("reporter_id", "target_type", "target_id",
-                         name="uq_reporter_target"),
-    )
-
-    # Relationships
-    reporter = relationship("User", back_populates="reports",
-                            foreign_keys=[reporter_id])
-    resolved_by_user = relationship("User", back_populates="resolved_reports",
-                                    foreign_keys=[resolved_by])
-    moderation_actions = relationship(
-        "ModerationAction",
-        back_populates="report",
-        cascade="all, delete-orphan",
-    )
-    appeals = relationship(
-        "Appeal",
-        back_populates="report",
-        cascade="all, delete-orphan",
-    )
-
-
-class ModerationAction(Base):
-    """A moderation action taken against a target."""
-
-    __tablename__ = "moderation_actions"
-
-    id = Column(Integer, primary_key=True, autoincrement=True)
-    moderator_id = Column(
-        Integer,
-        ForeignKey("users.id", ondelete="CASCADE"),
-        nullable=False,
-    )
-    target_user_id = Column(
-        Integer,
-        ForeignKey("users.id", ondelete="SET NULL"),
-        nullable=True,
-    )
-    target_type = Column(_target_type_enum, nullable=False)
-    target_id = Column(String(64), nullable=False)
-    action = Column(_moderation_action_enum, nullable=False)
-    reason = Column(Text, nullable=False)
-    report_id = Column(
-        Integer,
-        ForeignKey("reports.id", ondelete="SET NULL"),
-        nullable=True,
-    )
-    expires_at = Column(DateTime(timezone=True), nullable=True)
-    revoked_at = Column(DateTime(timezone=True), nullable=True)
-    created_at = Column(
-        DateTime(timezone=True),
-        server_default=func.now(),
-    )
-
-    # Relationships
-    moderator = relationship("User", back_populates="moderation_actions",
-                             foreign_keys=[moderator_id])
-    target_user = relationship("User", back_populates="moderation_actions_target",
-                               foreign_keys=[target_user_id])
-    report = relationship(
-        "Report",
-        back_populates="moderation_actions",
-    )
-    appeals = relationship(
-        "Appeal",
-        back_populates="moderation_action",
-        cascade="all, delete-orphan",
-    )
-
-
-class Appeal(Base):
-    """An appeal against a moderation action."""
-
-    __tablename__ = "appeals"
-
-    id = Column(Integer, primary_key=True, autoincrement=True)
-    moderation_action_id = Column(
-        Integer,
-        ForeignKey("moderation_actions.id", ondelete="CASCADE"),
-        nullable=False,
-    )
-    user_id = Column(
-        Integer,
-        ForeignKey("users.id", ondelete="CASCADE"),
-        nullable=False,
-    )
-    reason = Column(Text, nullable=False)
-    status = Column(
-        _appeal_status_enum,
-        nullable=False,
-        server_default="pending",
-    )
-    reviewed_by = Column(
-        Integer,
-        ForeignKey("users.id", ondelete="SET NULL"),
-        nullable=True,
-    )
-    reviewed_at = Column(DateTime(timezone=True), nullable=True)
-    created_at = Column(
-        DateTime(timezone=True),
-        server_default=func.now(),
-    )
-
-    # Prevent duplicate open appeals per sanction
-    __table_args__ = (
-        UniqueConstraint("moderation_action_id", "user_id",
-                         name="uq_action_user_appeal"),
-    )
-
-    # Relationships
-    moderation_action = relationship(
-        "ModerationAction",
-        back_populates="appeals",
-    )
-    user = relationship("User", back_populates="appeals")
-    reviewed_by_user = relationship("User", back_populates="reviewed_appeals",
-                                    foreign_keys=[reviewed_by])

backend/app/models/user.py

@@ -23,6 +23,8 @@ class User(Base):
     sessions = relationship("Session", back_populates="user", cascade="all, delete-orphan")
     worlds = relationship("World", back_populates="owner")
     assets = relationship("Asset", back_populates="owner")
+    owned_groups = relationship("Group", back_populates="owner")
+    group_memberships = relationship("GroupMember", back_populates="user")
 
     @property
     def is_adult(self) -> bool:

backend/docker-compose.yml

@@ -8,7 +8,7 @@ services:
       POSTGRES_PASSWORD: agp_password
       POSTGRES_DB: agp_db
     ports:
-      - "5432:5432"
+      - "${POSTGRES_PORT:-5432}:5432"
     volumes:
       - postgres_data:/var/lib/postgresql/data
     healthcheck:
@@ -20,7 +20,7 @@ services:
   redis:
     image: redis:7-alpine
     ports:
-      - "6379:6379"
+      - "${REDIS_PORT:-6379}:6379"
     volumes:
       - redis_data:/data
     healthcheck: