fix(likes): dedupe parallel toggles to prevent count inflation and 500s#84
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fix(likes): dedupe parallel toggles to prevent count inflation and 500s#84cursor[bot] wants to merge 1 commit into
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Concurrent like POSTs could insert duplicate rows for the same url+ipHash. That inflated counts and made .unique() throw on the next toggle (500s). Collect rows instead of unique(), delete duplicate rows after each toggle, and count distinct ipHashes in aggregate so reads stay correct. Co-authored-by: Injoon Oh <injoon5@icloud.com>
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Bug and impact
Parallel
POST /api/likesrequests (e.g. double-click) could both observe no existing row and insert duplicates for the sameurl+ipHash. That:countwasrows.length).unique()onby_url_ip, which throws when multiple rows exist → 500s and a broken like button for that visitor/pageSame class of race as the vote-count bug fixed in #71.
Root cause
likes.toggleused.unique()for read-modify-write without deduping duplicate rows created by overlapping mutations.Fix
by_url_iprows and delete extras before/after toggleipHashvalues per URL inaggregateso reads stay correct even if orphans existValidation
scripts/like-race-test.mjs(10 parallel toggles; fails if count jumps by >1)convex/lib/votes.js