PLAN-2857 unit U5, closes TASK-2997.
A MATERIALISED reverse index for `relation` field values —
`item_relation_links` per the ratified Q3 shape — plus a write hook, a
startup backfill, a viewer-scoped query, an endpoint, and the
"Referenced by N" section.
THE HOOK LIVES AT THE STORE'S FIELD-WRITING SITES, not at the doors the
row named. A door-level hook is a per-door wiring claim over a population
that GROWS; a store-level one cannot be bypassed by a door that does not
exist yet, and it is the shape migration 061 set for the content index.
The sites were enumerated with a grep rather than by eye, and two of them
are not in U1's resolver population at all.
Three placements are not obvious from the call sites: UPDATE re-reads the
blob FROM THE ROW, because a field write is a server-side MERGE and
indexing the submission would drop every key the caller did not mention;
MOVE indexes against the DESTINATION collection, the one write where blob
and schema change together; and the attachment remap calls the hook even
though it cannot change a relation value, because omitting it would be a
standing claim about what that function can touch.
A SCHEMA CHANGE REINDEXES THE COLLECTION (lead ruling), inside the
schema-update transaction and under the workspace lock, gated on the
schema or the values actually moving — an icon edit must not pay it.
Measured: 947ms-1.8s for 10k items, which is why it is inline and not a
job. The backfill batches by workspace in bounded chunks: 10k items in
1.06s across ~20 transactions, where one-per-item would have been 10,000.
THE COUNT IS THE VIEWER'S. ResolveBacklinksVisibility reused verbatim, so
"Referenced by 3" means "by 3 you can see" — a true count leaks the
existence of items the viewer cannot open. Filtering is in SQL so LIMIT
counts visible rows.
EIGHT CODEX ROUNDS, ELEVEN P1s; the first seven each found something
real. The ones worth keeping:
- the backfill's guard was "does the table have any row", and rows
commit per item, so an interrupted pass left it non-empty and
INCOMPLETE and skipped forever. Completion is recorded explicitly,
after the work.
- RESTORE is an eighth hook site. I enumerated writes of one COLUMN;
the index depends on (blob, schema, LIVENESS). That miss produced the
input matrix on TASK-2997's trail, which round 4 then validated row
by row.
- the backfill SKIPPED zero-edge items as an optimisation — precisely
the case that preserves a stale row and then marks the pass complete.
- a source in a SOFT-DELETED COLLECTION was disclosed; its items stay
live and an Unrestricted viewer has no collection filter to catch it.
- rounds 3 and 4 were the same miss at two scopes: I locked what I was
READING and not what whose change invalidates the read. Round 3 also
refuted a claim I had put in a commit message, and the record was
corrected rather than left standing.
- the field-label lookup added in round 6 BECAME round 7's P1: a
per-collection SELECT while the rows cursor was open, which is
BUG-2409's deadlock class. One query now, with a MaxOpenConns(1)
guard that the restored shape kills.
Three times a comment described code that had changed under it,
including one claiming a counterfactual TEST that does not exist — the
counterfactual is a mutation, recorded per round with its verdict.
Q3'S COUNTERFACTUAL, re-run after every rewrite: hook removed, mutant
COMPILES, all legs fail. Per-site too, because "all sites wired" is
otherwise untested.
NOT COVERED, said plainly: the Postgres interleavings are argued from the
isolation level and the lock order, not demonstrated — SQLite serialises
writes and cannot express the race. Two hook sites are uncovered, one
unfalsifiable by construction and one with no caller.
BUG-3017 files the pre-existing attachment-remap lost update this
branch's workspace lock closes, so it is on the record rather than
absorbed here.
Gates: go test ./... 0, vet 0, gofmt clean, lint 0 issues, svelte-check 0
errors, make test-pg 0 with all 17 relation tests confirmed run BY NAME
on Postgres. All 8 CI checks green on 8c0fe775.
Claude-Session: https://claude.ai/code/session_01PRcuviXka4Un1FGrBrX8jc
xarmian
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