snapshot of https://github.com/tldraw/tldraw.git (main, 2026-09-23; blobs > 131072B omitted)

apps/dotcom/zero-cache/migrations/043_add_comment_reactions.sql

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+-- Emoji reactions on comments, written by the file's Durable Object from the room's
+-- comment-reaction records (see TLCommentReaction in tlschema). Same contract as comment and
+-- comment_thread: Postgres is the sole durable store, the columns carry every record field so the
+-- Durable Object can rebuild the records from rows alone on cold start, and `lastChangedClock`
+-- preserves each record's sync clock and guards upserts against no-op replays.
+--
+-- A reaction is its own row rather than a column on comment because it is one user's data about
+-- someone else's comment — the same reason comment_read is its own table. It keeps every write
+-- scoped to one user's own record, so concurrent reactions from different people can't overwrite
+-- each other, and a user can never write a reaction attributed to anyone else.
+--
+-- `meta` and `lastChangedClock` are persistence/rehydration columns not declared in the Zero
+-- schema, so they never reach clients.
+
+CREATE TABLE comment_reaction (
+  "id" VARCHAR PRIMARY KEY,
+  "fileId" VARCHAR NOT NULL,
+  "commentId" VARCHAR NOT NULL,
+  "threadId" VARCHAR NOT NULL,
+  "pageId" VARCHAR NOT NULL,
+  "userId" VARCHAR NOT NULL,
+  "emoji" VARCHAR NOT NULL,
+  "createdAt" BIGINT NOT NULL,
+  "meta" JSONB NOT NULL,
+  "lastChangedClock" BIGINT NOT NULL,
+  CONSTRAINT comment_reaction_file_id_fkey FOREIGN KEY ("fileId") REFERENCES public."file"("id") ON DELETE CASCADE,
+  CONSTRAINT comment_reaction_comment_id_fkey FOREIGN KEY ("commentId") REFERENCES public."comment"("id") ON DELETE CASCADE,
+  CONSTRAINT comment_reaction_thread_id_fkey FOREIGN KEY ("threadId") REFERENCES public."comment_thread"("id") ON DELETE CASCADE,
+  -- deleting a user removes their reactions, never the comment they reacted to
+  CONSTRAINT comment_reaction_user_id_fkey FOREIGN KEY ("userId") REFERENCES public."user"("id") ON DELETE CASCADE,
+  -- one record per (comment, user, emoji): a user may hold multiple reactions on a comment (one
+  -- per emoji), but not the same emoji twice. The record id is derived from the same triple
+  -- (createCommentReactionId), so this backstops the invariant at the database.
+  CONSTRAINT comment_reaction_comment_user_emoji_unique UNIQUE ("commentId", "userId", "emoji")
+);
+
+CREATE INDEX comment_reaction_file_id_idx ON comment_reaction("fileId");
+CREATE INDEX comment_reaction_comment_id_idx ON comment_reaction("commentId");
+CREATE INDEX comment_reaction_thread_id_idx ON comment_reaction("threadId");
+-- covers the user-delete cascade path
+CREATE INDEX comment_reaction_user_id_idx ON comment_reaction("userId");
+
+ALTER PUBLICATION zero_data ADD TABLE public."comment_reaction";