Add edit and delete discussions and comments

app/backend/src/couchers/i18n/locales/en.json

@@ -54,7 +54,13 @@
     "date_from_before_today": "From date must be today or later.",
     "date_to_after_one_year": "You cannot request to stay with someone for longer than one year.",
     "dev_apis_disabled": "Development APIs are not enabled on this server.",
+    "discussion_delete_permission_denied": "You are not allowed to delete this discussion.",
+    "discussion_deleted": "This discussion has been deleted.",
+    "discussion_edit_permission_denied": "You are not allowed to edit this discussion.",
     "discussion_not_found": "Discussion not found.",
+    "reply_delete_permission_denied": "You are not allowed to delete this comment.",
+    "reply_deleted": "This comment has been deleted.",
+    "reply_edit_permission_denied": "You are not allowed to edit this comment.",
     "discussions_not_enabled": "Discussions are not enabled in this group or community.",
     "do_not_email_cannot_host": "You cannot enable hosting while you have emails turned off in your settings.",
     "do_not_email_cannot_meet": "You cannot enable meeting up while you have emails turned off in your settings.",

app/backend/src/couchers/migrations/versions/0165_add_edit_delete_to_discussions_and_comments.py

@@ -0,0 +1,101 @@
+"""Add edit/delete support to discussions, comments, and replies
+
+Revision ID: 0165
+Revises: 0164
+Create Date: 2026-05-13 00:00:00.000000
+
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = "0165"
+down_revision = "0164"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "discussions",
+        sa.Column("deleted", sa.DateTime(timezone=True), nullable=True),
+    )
+    op.add_column(
+        "discussions",
+        sa.Column("last_edited", sa.DateTime(timezone=True), nullable=True),
+    )
+    op.add_column(
+        "comments",
+        sa.Column("last_edited", sa.DateTime(timezone=True), nullable=True),
+    )
+    op.add_column(
+        "replies",
+        sa.Column("last_edited", sa.DateTime(timezone=True), nullable=True),
+    )
+
+    op.create_table(
+        "discussion_versions",
+        sa.Column("id", sa.BigInteger(), nullable=False),
+        sa.Column("discussion_id", sa.BigInteger(), nullable=False),
+        sa.Column("editor_user_id", sa.BigInteger(), nullable=False),
+        sa.Column("change_type", sa.Enum("edit", "delete", name="contentchangetype"), nullable=False),
+        sa.Column("old_title", sa.String(), nullable=True),
+        sa.Column("new_title", sa.String(), nullable=True),
+        sa.Column("old_content", sa.String(), nullable=True),
+        sa.Column("new_content", sa.String(), nullable=True),
+        sa.Column("created", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.ForeignKeyConstraint(["discussion_id"], ["discussions.id"]),
+        sa.ForeignKeyConstraint(["editor_user_id"], ["users.id"]),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index("ix_discussion_versions_discussion_id", "discussion_versions", ["discussion_id"])
+    op.create_index("ix_discussion_versions_editor_user_id", "discussion_versions", ["editor_user_id"])
+
+    op.create_table(
+        "comment_versions",
+        sa.Column("id", sa.BigInteger(), nullable=False),
+        sa.Column("comment_id", sa.BigInteger(), nullable=False),
+        sa.Column("editor_user_id", sa.BigInteger(), nullable=False),
+        sa.Column(
+            "change_type", sa.Enum("edit", "delete", name="contentchangetype", create_type=False), nullable=False
+        ),
+        sa.Column("old_content", sa.String(), nullable=True),
+        sa.Column("new_content", sa.String(), nullable=True),
+        sa.Column("created", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.ForeignKeyConstraint(["comment_id"], ["comments.id"]),
+        sa.ForeignKeyConstraint(["editor_user_id"], ["users.id"]),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index("ix_comment_versions_comment_id", "comment_versions", ["comment_id"])
+    op.create_index("ix_comment_versions_editor_user_id", "comment_versions", ["editor_user_id"])
+
+    op.create_table(
+        "reply_versions",
+        sa.Column("id", sa.BigInteger(), nullable=False),
+        sa.Column("reply_id", sa.BigInteger(), nullable=False),
+        sa.Column("editor_user_id", sa.BigInteger(), nullable=False),
+        sa.Column(
+            "change_type", sa.Enum("edit", "delete", name="contentchangetype", create_type=False), nullable=False
+        ),
+        sa.Column("old_content", sa.String(), nullable=True),
+        sa.Column("new_content", sa.String(), nullable=True),
+        sa.Column("created", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.ForeignKeyConstraint(["reply_id"], ["replies.id"]),
+        sa.ForeignKeyConstraint(["editor_user_id"], ["users.id"]),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index("ix_reply_versions_reply_id", "reply_versions", ["reply_id"])
+    op.create_index("ix_reply_versions_editor_user_id", "reply_versions", ["editor_user_id"])
+
+
+def downgrade() -> None:
+    op.drop_table("reply_versions")
+    op.drop_table("comment_versions")
+    op.drop_table("discussion_versions")
+    sa.Enum(name="contentchangetype").drop(op.get_bind(), checkfirst=True)
+
+    op.drop_column("replies", "last_edited")
+    op.drop_column("comments", "last_edited")
+    op.drop_column("discussions", "last_edited")
+    op.drop_column("discussions", "deleted")

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

@@ -1,7 +1,8 @@
+import enum
 from datetime import datetime
 from typing import TYPE_CHECKING
 
-from sqlalchemy import BigInteger, DateTime, ForeignKey, String, UniqueConstraint, func
+from sqlalchemy import BigInteger, DateTime, Enum, ForeignKey, String, UniqueConstraint, func
 from sqlalchemy.orm import Mapped, column_property, mapped_column, relationship
 
 from couchers.models.base import Base, communities_seq
@@ -29,6 +30,8 @@ class Discussion(Base, kw_only=True):
     thread_id: Mapped[int] = mapped_column(ForeignKey("threads.id"), unique=True)
     moderation_state_id: Mapped[int] = mapped_column(ForeignKey("moderation_states.id"), index=True)
     created: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), init=False)
+    deleted: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), default=None)
+    last_edited: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), default=None)
 
     creator_user_id: Mapped[int] = mapped_column(ForeignKey("users.id"), index=True)
     owner_cluster_id: Mapped[int] = mapped_column(ForeignKey("clusters.id"), index=True)
@@ -96,6 +99,7 @@ class Comment(Base, kw_only=True):
     content: Mapped[str] = mapped_column(String)  # CommonMark without images
     created: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), init=False)
     deleted: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), default=None)
+    last_edited: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), default=None)
 
     thread: Mapped[Thread] = relationship(init=False, backref="comments")
 
@@ -117,10 +121,84 @@ class Reply(Base, kw_only=True):
     content: Mapped[str] = mapped_column(String)  # CommonMark without images
     created: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), init=False)
     deleted: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), default=None)
+    last_edited: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), default=None)
 
     comment: Mapped[Comment] = relationship(init=False, backref="replies")
 
 
+class ContentChangeType(enum.Enum):
+    edit = enum.auto()
+    delete = enum.auto()
+
+
+class DiscussionVersion(Base, kw_only=True):
+    """
+    audit log of edits and deletions to discussions
+    """
+
+    __tablename__ = "discussion_versions"
+
+    id: Mapped[int] = mapped_column(BigInteger, primary_key=True, init=False)
+
+    discussion_id: Mapped[int] = mapped_column(ForeignKey("discussions.id"), index=True)
+    editor_user_id: Mapped[int] = mapped_column(ForeignKey("users.id"), index=True)
+    change_type: Mapped[ContentChangeType] = mapped_column(Enum(ContentChangeType))
+    old_title: Mapped[str | None] = mapped_column(String, default=None)
+    new_title: Mapped[str | None] = mapped_column(String, default=None)
+    old_content: Mapped[str | None] = mapped_column(String, default=None)
+    new_content: Mapped[str | None] = mapped_column(String, default=None)
+    created: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), init=False)
+
+    discussion: Mapped[Discussion] = relationship(init=False, backref="versions")
+    editor_user: Mapped[User] = relationship(
+        init=False, backref="edited_discussions", foreign_keys="DiscussionVersion.editor_user_id"
+    )
+
+
+class CommentVersion(Base, kw_only=True):
+    """
+    audit log of edits and deletions to comments
+    """
+
+    __tablename__ = "comment_versions"
+
+    id: Mapped[int] = mapped_column(BigInteger, primary_key=True, init=False)
+
+    comment_id: Mapped[int] = mapped_column(ForeignKey("comments.id"), index=True)
+    editor_user_id: Mapped[int] = mapped_column(ForeignKey("users.id"), index=True)
+    change_type: Mapped[ContentChangeType] = mapped_column(Enum(ContentChangeType))
+    old_content: Mapped[str | None] = mapped_column(String, default=None)
+    new_content: Mapped[str | None] = mapped_column(String, default=None)
+    created: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), init=False)
+
+    comment: Mapped[Comment] = relationship(init=False, backref="versions")
+    editor_user: Mapped[User] = relationship(
+        init=False, backref="edited_comments", foreign_keys="CommentVersion.editor_user_id"
+    )
+
+
+class ReplyVersion(Base, kw_only=True):
+    """
+    audit log of edits and deletions to replies
+    """
+
+    __tablename__ = "reply_versions"
+
+    id: Mapped[int] = mapped_column(BigInteger, primary_key=True, init=False)
+
+    reply_id: Mapped[int] = mapped_column(ForeignKey("replies.id"), index=True)
+    editor_user_id: Mapped[int] = mapped_column(ForeignKey("users.id"), index=True)
+    change_type: Mapped[ContentChangeType] = mapped_column(Enum(ContentChangeType))
+    old_content: Mapped[str | None] = mapped_column(String, default=None)
+    new_content: Mapped[str | None] = mapped_column(String, default=None)
+    created: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now(), init=False)
+
+    reply: Mapped[Reply] = relationship(init=False, backref="versions")
+    editor_user: Mapped[User] = relationship(
+        init=False, backref="edited_replies", foreign_keys="ReplyVersion.editor_user_id"
+    )
+
+
 class ClusterDiscussionAssociation(Base, kw_only=True):
     """
     discussions related to clusters

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

@@ -45,6 +45,12 @@
     UserAdminTag,
     UserBadge,
 )
+from couchers.models.discussions import (
+    CommentVersion,
+    ContentChangeType,
+    DiscussionVersion,
+    ReplyVersion,
+)
 from couchers.models.notifications import NotificationTopicAction
 from couchers.models.uploads import Upload, has_avatar_photo_expression
 from couchers.notifications.notify import notify
@@ -987,6 +993,30 @@ def EditDiscussion(
             discussion.content = request.new_content.strip()
         return empty_pb2.Empty()
 
+    def DeleteDiscussion(
+        self, request: admin_pb2.AdminDeleteDiscussionReq, context: CouchersContext, session: Session
+    ) -> empty_pb2.Empty:
+        discussion = session.execute(
+            select(Discussion).where(Discussion.id == request.discussion_id)
+        ).scalar_one_or_none()
+        if not discussion:
+            context.abort_with_error_code(grpc.StatusCode.NOT_FOUND, "discussion_not_found")
+        if discussion.deleted is not None:
+            return empty_pb2.Empty()
+        session.add(
+            DiscussionVersion(
+                discussion_id=discussion.id,
+                editor_user_id=context.user_id,
+                change_type=ContentChangeType.delete,
+                old_title=discussion.title,
+                new_title=None,
+                old_content=discussion.content,
+                new_content=None,
+            )
+        )
+        discussion.deleted = now()
+        return empty_pb2.Empty()
+
     def EditReply(self, request: admin_pb2.EditReplyReq, context: CouchersContext, session: Session) -> empty_pb2.Empty:
         database_id, depth = unpack_thread_id(request.reply_id)
         if depth == 1:
@@ -1000,7 +1030,29 @@ def EditReply(self, request: admin_pb2.EditReplyReq, context: CouchersContext, s
 
         if not obj:
             context.abort_with_error_code(grpc.StatusCode.NOT_FOUND, "object_not_found")
-        obj.content = request.new_content.strip()
+        old_content = obj.content
+        new_content = request.new_content.strip()
+        if depth == 1:
+            session.add(
+                CommentVersion(
+                    comment_id=database_id,
+                    editor_user_id=context.user_id,
+                    change_type=ContentChangeType.edit,
+                    old_content=old_content,
+                    new_content=new_content,
+                )
+            )
+        else:
+            session.add(
+                ReplyVersion(
+                    reply_id=database_id,
+                    editor_user_id=context.user_id,
+                    change_type=ContentChangeType.edit,
+                    old_content=old_content,
+                    new_content=new_content,
+                )
+            )
+        obj.content = new_content
         return empty_pb2.Empty()
 
     def AddUsersToModerationUserList(

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

@@ -18,6 +18,7 @@
     Cluster,
     ClusterRole,
     ClusterSubscription,
+    Comment,
     Discussion,
     Event,
     EventOccurrence,
@@ -32,7 +33,7 @@
 from couchers.servicers.events import event_to_pb
 from couchers.servicers.groups import group_to_pb
 from couchers.servicers.pages import page_to_pb
-from couchers.sql import to_bool, users_visible, where_moderated_content_visible
+from couchers.sql import to_bool, users_visible, where_moderated_content_visible, where_users_column_visible
 from couchers.utils import Timestamp_from_datetime, dt_from_millis, millis_from_dt, now
 
 logger = logging.getLogger(__name__)
@@ -465,19 +466,46 @@ def ListDiscussions(
         self, request: communities_pb2.ListDiscussionsReq, context: CouchersContext, session: Session
     ) -> communities_pb2.ListDiscussionsRes:
         page_size = min(MAX_PAGINATION_LENGTH, request.page_size or MAX_PAGINATION_LENGTH)
-        next_page_id = int(request.page_token) if request.page_token else 0
+        next_page_id = int(request.page_token) if request.page_token else 2**63 - 1
         node = session.execute(select(Node).where(Node.id == request.community_id)).scalar_one_or_none()
         if not node:
             context.abort_with_error_code(grpc.StatusCode.NOT_FOUND, "community_not_found")
         if not node.official_cluster.small_community_features_enabled:
             context.abort_with_error_code(grpc.StatusCode.FAILED_PRECONDITION, "discussions_not_enabled")
-        query = (
-            select(Discussion)
-            .where(Discussion.owner_cluster_id == node.official_cluster.id)
-            .where(or_(Discussion.id <= next_page_id, to_bool(next_page_id == 0)))
+        has_visible_comments = (
+            where_moderated_content_visible(
+                where_users_column_visible(
+                    select(func.count())
+                    .select_from(Comment)
+                    .where(Comment.thread_id == Discussion.thread_id)
+                    .where(Comment.deleted == None),
+                    context,
+                    Comment.author_user_id,
+                ),
+                context,
+                Comment,
+                is_list_operation=True,
+            )
+            .correlate(Discussion)
+            .scalar_subquery()
+        )
+        discussions = (
+            session.execute(
+                where_moderated_content_visible(
+                    select(Discussion)
+                    .where(Discussion.owner_cluster_id == node.official_cluster.id)
+                    .where((Discussion.deleted == None) | (has_visible_comments > 0))
+                    .where(Discussion.id <= next_page_id)
+                    .order_by(Discussion.id.desc())
+                    .limit(page_size + 1),
+                    context,
+                    Discussion,
+                    is_list_operation=True,
+                )
+            )
+            .scalars()
+            .all()
         )
-        query = where_moderated_content_visible(query, context, Discussion, is_list_operation=True)
-        discussions = session.execute(query.order_by(Discussion.id.desc()).limit(page_size + 1)).scalars().all()
         return communities_pb2.ListDiscussionsRes(
             discussions=[discussion_to_pb(session, discussion, context) for discussion in discussions[:page_size]],
             next_page_token=str(discussions[-1].id) if len(discussions) > page_size else None,