mirror of
https://github.com/PerpetualSoftware/pad.git
synced 2026-09-12 05:49:00 +00:00
xarmian
40f88052cd
Version restore didn't reconcile the live Y.Doc: peers kept editing a Y.Doc built on pre-restore ops, and their next collab-snapshot flush clobbered the restored items.content. Reworked restore to prune+reseed — the restored content becomes canonical and every peer converges on it (unflushed edits are discarded, which is exactly restore semantics), replacing the earlier applier/epoch/watermark routing. handleRestoreItemVersion drives RoomManager.ForceRefreshRoom under the per-item lock. Hardened across Codex xhigh review rounds: - Atomicity: pre-prune MAX(op-log), the items.content write, the "Restored from…" version, the op-log wipe, AND both durable restore boundaries all run in ONE store transaction. A failed commit rolls back all of it — no divergent state, no fail-open boundary. - Unambiguous commit signal: UpdateItem reads the updated row WITHIN the tx (getItemTx) before commit, so a read failure can't make a committed update look failed and the returned seq is this restore's. - Restore freeze: conns are paused via a dedicated rc.frozen flag (NOT canWrite) so the auth-revalidation loop can't thaw the freeze mid-restore or promote a viewer; pickApplier + the applier-ack handler reject frozen conns so a concurrent external PATCH can't falsely succeed. - Stale-flush boundary: pre-prune MAX+1 fences in-flight snapshot cursors under the same item lock. - force_refresh fan-out deadlock: per-conn timer-close so a wedged writeLoop can't hang the fan-out + item lock. - Stale-SEED clobber: the client announces the item.seq it seeded from (?content_seq=) on every (re)connect; Join force_refreshes any seed that predates the last restore. Residual #1 (restart-durability) CLOSED durably, for BOTH stale vectors — the in-memory fences didn't survive a restart, so a surviving cursor-0 pre-restore browser tab wasn't fenced on reconnect. Two nullable per-item columns (migration 075 SQLite / pg 053), both stamped in the restore's own tx (atomic with the content write + op-log prune): * items.last_restore_seq — the content generation. Join's stale-seed fence reads it (via store.ItemLastRestoreSeq) when the in-memory fast-path misses (after a restart); if that read errors, Join fails CLOSED via a RETRYABLE plain close (not a force_refresh, which would discard the Y.Doc and spin an unbounded refresh loop) so the client reconnects with backoff, Y.Doc intact. * items.restore_boundary_op_id — the op-log-id boundary. The collab-snapshot flush gate reads it (via store.ItemRestoreBoundaryOpID) when the in-memory RestoreBoundary misses (after a restart), failing closed (409) on a read error, so a surviving tab's stale HTTP flush is fenced too. No SCHEMA_VERSION bump — durable columns are not a Y.Doc node-spec change. Deferred to BUG-2276: (a) a Postgres commit whose ack is lost is treated as rolled-back (needs commit-outcome reconciliation; SQLite unaffected); (b) a restore rollback racing an in-flight external-applier ack can drop the ack and retry/fall back (needs the applier flow serialised under itemLock at a 30s-stall cost). NOTE(BUG-2270): ForceVersion can mint same-second version rows; the item_versions ordering tie-breaker is tracked separately. Claude-Session: https://claude.ai/code/session_01EZ6yr6pAUFb1uffan912ra