Backend/moderation: UMS coverage for thread comments and replies

app/backend/src/couchers/migrations/versions/0152_backend_moderation_ums_coverage_for_.py

@@ -0,0 +1,145 @@
+"""Backend/moderation: UMS coverage for thread comments and replies
+
+Revision ID: 0152
+Revises: 0151
+Create Date: 2026-05-10 00:57:29.125757
+
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "0152"
+down_revision = "0151"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # Add 'comment' and 'reply' to the ModerationObjectType enum.
+    # Must use rename/recreate pattern instead of ADD VALUE, because ADD VALUE
+    # cannot be used in the same transaction as DML that references the new value.
+    op.execute("ALTER TYPE moderationobjecttype RENAME TO moderationobjecttype_old")
+    op.execute(
+        "CREATE TYPE moderationobjecttype AS ENUM "
+        "('host_request', 'group_chat', 'friend_request', 'event_occurrence', 'comment', 'reply')"
+    )
+    op.execute("""
+        ALTER TABLE moderation_states
+        ALTER COLUMN object_type TYPE moderationobjecttype
+        USING object_type::text::moderationobjecttype
+    """)
+    op.execute("DROP TYPE moderationobjecttype_old")
+
+    # Add moderation_state_id columns as nullable so we can backfill before enforcing NOT NULL.
+    op.add_column("comments", sa.Column("moderation_state_id", sa.BigInteger(), nullable=True))
+    op.add_column("replies", sa.Column("moderation_state_id", sa.BigInteger(), nullable=True))
+
+    # Backfill moderation states for existing comments (using the < 2000000 ID range reserved for backfills)
+    op.execute("""
+        INSERT INTO moderation_states (id, object_type, object_id, visibility)
+        SELECT
+            (SELECT COALESCE(MAX(id), 0) FROM moderation_states WHERE id < 2000000) + ROW_NUMBER() OVER (ORDER BY id),
+            'comment',
+            id,
+            'visible'
+        FROM comments
+    """)
+    op.execute("""
+        INSERT INTO moderation_log (id, moderation_state_id, action, moderator_user_id, new_visibility, reason)
+        SELECT
+            (SELECT GREATEST(
+                COALESCE((SELECT MAX(id) FROM moderation_states WHERE id < 2000000), 0),
+                COALESCE((SELECT MAX(id) FROM moderation_log WHERE id < 2000000), 0)
+            )) + ROW_NUMBER() OVER (ORDER BY c.id),
+            ms.id,
+            'create',
+            c.author_user_id,
+            'visible',
+            'Migration: existing comment'
+        FROM moderation_states ms
+        JOIN comments c ON ms.object_id = c.id AND ms.object_type = 'comment'
+    """)
+    op.execute("""
+        UPDATE comments
+        SET moderation_state_id = moderation_states.id
+        FROM moderation_states
+        WHERE moderation_states.object_type = 'comment'
+        AND moderation_states.object_id = comments.id
+    """)
+
+    # Backfill moderation states for existing replies (using the < 2000000 ID range reserved for backfills)
+    op.execute("""
+        INSERT INTO moderation_states (id, object_type, object_id, visibility)
+        SELECT
+            (SELECT COALESCE(MAX(id), 0) FROM moderation_states WHERE id < 2000000) + ROW_NUMBER() OVER (ORDER BY id),
+            'reply',
+            id,
+            'visible'
+        FROM replies
+    """)
+    op.execute("""
+        INSERT INTO moderation_log (id, moderation_state_id, action, moderator_user_id, new_visibility, reason)
+        SELECT
+            (SELECT GREATEST(
+                COALESCE((SELECT MAX(id) FROM moderation_states WHERE id < 2000000), 0),
+                COALESCE((SELECT MAX(id) FROM moderation_log WHERE id < 2000000), 0)
+            )) + ROW_NUMBER() OVER (ORDER BY r.id),
+            ms.id,
+            'create',
+            r.author_user_id,
+            'visible',
+            'Migration: existing reply'
+        FROM moderation_states ms
+        JOIN replies r ON ms.object_id = r.id AND ms.object_type = 'reply'
+    """)
+    op.execute("""
+        UPDATE replies
+        SET moderation_state_id = moderation_states.id
+        FROM moderation_states
+        WHERE moderation_states.object_type = 'reply'
+        AND moderation_states.object_id = replies.id
+    """)
+
+    # Now enforce NOT NULL and add the index + FK constraints.
+    op.alter_column("comments", "moderation_state_id", nullable=False)
+    op.create_index(op.f("ix_comments_moderation_state_id"), "comments", ["moderation_state_id"], unique=False)
+    op.create_foreign_key(
+        op.f("fk_comments_moderation_state_id_moderation_states"),
+        "comments",
+        "moderation_states",
+        ["moderation_state_id"],
+        ["id"],
+    )
+
+    op.alter_column("replies", "moderation_state_id", nullable=False)
+    op.create_index(op.f("ix_replies_moderation_state_id"), "replies", ["moderation_state_id"], unique=False)
+    op.create_foreign_key(
+        op.f("fk_replies_moderation_state_id_moderation_states"),
+        "replies",
+        "moderation_states",
+        ["moderation_state_id"],
+        ["id"],
+    )
+
+
+def downgrade() -> None:
+    op.drop_constraint(op.f("fk_replies_moderation_state_id_moderation_states"), "replies", type_="foreignkey")
+    op.drop_index(op.f("ix_replies_moderation_state_id"), table_name="replies")
+    op.drop_column("replies", "moderation_state_id")
+    op.drop_constraint(op.f("fk_comments_moderation_state_id_moderation_states"), "comments", type_="foreignkey")
+    op.drop_index(op.f("ix_comments_moderation_state_id"), table_name="comments")
+    op.drop_column("comments", "moderation_state_id")
+
+    # Clean up moderation data for comments and replies.
+    op.execute("""
+        DELETE FROM moderation_log
+        WHERE moderation_state_id IN (
+            SELECT id FROM moderation_states WHERE object_type IN ('comment', 'reply')
+        )
+    """)
+    op.execute("DELETE FROM moderation_states WHERE object_type IN ('comment', 'reply')")
+
+    # Note: we cannot remove enum values in PostgreSQL easily, so we leave 'comment'/'reply'
+    # in the moderationobjecttype enum.

app/backend/src/couchers/models/discussions.py

@@ -81,10 +81,12 @@ class Comment(Base, kw_only=True):
     """
 
     __tablename__ = "comments"
+    __moderation_author_column__ = "author_user_id"
 
     id: Mapped[int] = mapped_column(BigInteger, primary_key=True, init=False)
 
     thread_id: Mapped[int] = mapped_column(ForeignKey("threads.id"), index=True)
+    moderation_state_id: Mapped[int] = mapped_column(ForeignKey("moderation_states.id"), index=True)
     author_user_id: Mapped[int] = mapped_column(ForeignKey("users.id"))
     content: Mapped[str] = mapped_column(String)  # CommonMark without images
     created: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), init=False)
@@ -99,10 +101,12 @@ class Reply(Base, kw_only=True):
     """
 
     __tablename__ = "replies"
+    __moderation_author_column__ = "author_user_id"
 
     id: Mapped[int] = mapped_column(BigInteger, primary_key=True, init=False)
 
     comment_id: Mapped[int] = mapped_column(ForeignKey("comments.id"), index=True)
+    moderation_state_id: Mapped[int] = mapped_column(ForeignKey("moderation_states.id"), index=True)
     author_user_id: Mapped[int] = mapped_column(ForeignKey("users.id"))
     content: Mapped[str] = mapped_column(String)  # CommonMark without images
     created: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), init=False)

app/backend/src/couchers/models/moderation.py

@@ -66,6 +66,8 @@ class ModerationObjectType(enum.Enum):
     group_chat = enum.auto()
     friend_request = enum.auto()
     event_occurrence = enum.auto()
+    comment = enum.auto()
+    reply = enum.auto()
 
 
 class ModerationState(Base, kw_only=True):

app/backend/src/couchers/servicers/discussions.py

@@ -41,7 +41,7 @@ def discussion_to_pb(session: Session, discussion: Discussion, context: Couchers
         owner_title=discussion.owner_cluster.name,
         title=discussion.title,
         content=discussion.content,
-        thread=thread_to_pb(session, discussion.thread_id),
+        thread=thread_to_pb(session, context, discussion.thread_id),
         can_moderate=can_moderate,
     )
 

app/backend/src/couchers/servicers/events.py

@@ -204,7 +204,7 @@ def event_to_pb(session: Session, occurrence: EventOccurrence, context: Couchers
         owner_user_id=event.owner_user_id,
         owner_community_id=owner_community_id,
         owner_group_id=owner_group_id,
-        thread=thread_to_pb(session, event.thread_id),
+        thread=thread_to_pb(session, context, event.thread_id),
         can_edit=can_edit,
         can_moderate=can_moderate,
     )

app/backend/src/couchers/servicers/moderation.py

@@ -16,6 +16,7 @@
 )
 from couchers.models import (
     AdminActionLevel,
+    Comment,
     Event,
     EventOccurrence,
     FriendRelationship,
@@ -32,6 +33,7 @@
     ModerationVisibility,
     Notification,
     NotificationDelivery,
+    Reply,
     User,
 )
 from couchers.proto import moderation_pb2, moderation_pb2_grpc
@@ -104,6 +106,8 @@
     ModerationObjectType.group_chat: moderation_pb2.MODERATION_OBJECT_TYPE_GROUP_CHAT,
     ModerationObjectType.friend_request: moderation_pb2.MODERATION_OBJECT_TYPE_FRIEND_REQUEST,
     ModerationObjectType.event_occurrence: moderation_pb2.MODERATION_OBJECT_TYPE_EVENT_OCCURRENCE,
+    ModerationObjectType.comment: moderation_pb2.MODERATION_OBJECT_TYPE_COMMENT,
+    ModerationObjectType.reply: moderation_pb2.MODERATION_OBJECT_TYPE_REPLY,
 }
 
 moderationobjecttype2sql = {
@@ -112,6 +116,8 @@
     moderation_pb2.MODERATION_OBJECT_TYPE_GROUP_CHAT: ModerationObjectType.group_chat,
     moderation_pb2.MODERATION_OBJECT_TYPE_FRIEND_REQUEST: ModerationObjectType.friend_request,
     moderation_pb2.MODERATION_OBJECT_TYPE_EVENT_OCCURRENCE: ModerationObjectType.event_occurrence,
+    moderation_pb2.MODERATION_OBJECT_TYPE_COMMENT: ModerationObjectType.comment,
+    moderation_pb2.MODERATION_OBJECT_TYPE_REPLY: ModerationObjectType.reply,
 }
 
 # Mapping from ModerationObjectType to the SQLAlchemy model class
@@ -120,6 +126,8 @@
     ModerationObjectType.group_chat: GroupChat,
     ModerationObjectType.friend_request: FriendRelationship,
     ModerationObjectType.event_occurrence: EventOccurrence,
+    ModerationObjectType.comment: Comment,
+    ModerationObjectType.reply: Reply,
 }
 
 
@@ -251,6 +259,14 @@ def moderation_state_to_pb(state: ModerationState, session: Session) -> moderati
             .where(EventOccurrence.id == object_id)
         ).one()
         content = f"{title}\n\n{description}"
+    elif object_type == ModerationObjectType.comment:
+        author_user_id, content = session.execute(
+            select(Comment.author_user_id, Comment.content).where(Comment.id == object_id)
+        ).one()
+    elif object_type == ModerationObjectType.reply:
+        author_user_id, content = session.execute(
+            select(Reply.author_user_id, Reply.content).where(Reply.id == object_id)
+        ).one()
     else:
         raise ValueError(f"Unsupported moderation object type: {object_type}")
 

app/backend/src/couchers/servicers/pages.py

@@ -78,7 +78,7 @@ def page_to_pb(session: Session, page: Page, context: CouchersContext) -> pages_
         owner_user_id=page.owner_user_id,
         owner_community_id=owner_community_id,
         owner_group_id=owner_group_id,
-        thread=thread_to_pb(session, page.thread_id),
+        thread=thread_to_pb(session, context, page.thread_id),
         title=current_version.title,
         content=current_version.content,
         photo_url=current_version.photo.full_url if current_version.photo_key else None,