## The defect
On a board declaring more than one complete-trait column — a merged lane
and a shipped lane, say — a card landing in the **second** one was never
recognised as finished, so nothing unblocked its dependents. Silent: no
error, the dependent just waits.
Two problems, the same shape:
1. **`TaskMoveLanes` carried one id per role.** That is right for
*"where should this card go"* and wrong for *"is this column one of the
finished lanes"*, which is a **membership** question. The payload could
not express such a board at all.
2. **`mergeParkedColumns` rebuilt `terminal` as `new Set([complete,
archived])`** — discarding `base.terminal`, which the sync IR path had
already resolved correctly, and narrowing a membership set back to
first-match-per-role.
Point 2 contradicted the note sitting directly above it in the same
file:
> `terminal` is a MEMBERSHIP set, and it is not the same question as
`complete`/`archived`. […] A workflow may declare more than one
complete-trait column […] and `to === parked.complete` sees only the
first and silently skips the rest.
The reasoning was already written down. The overlay added later didn't
honour it.
## Fix
`TaskMoveLanes.terminal?: readonly string[]`, filled from
`columnsWithFlag(ir, "complete"|"archived")` rather than the first-match
`resolveLifecycleColumns`, and the merge is now a **union** of base,
payload, and the single lanes.
Optional, so all 12 emitters and every listener keep compiling — a
listener that ignores it is exactly as correct as before. Union is the
direction `scheduler.ts` already argues for at line ~422: a superset
costs one extra query; a subset **silently withholds work from a
finished card**.
`complete` deliberately stays first-match — a set would be the wrong
shape for a move *target*. Both questions now coexist rather than one
replacing the other.
## How it was found, and what it corrects
Supplying `task:moved` lanes fixed every *other* renamed-board case in
`scheduler-renamed-hold-events` — measured **10 passed / 1 failed** —
and left exactly this one broken. That same measurement is why I
narrowed my earlier claim on #3082: the other behaviours were never
broken in production, because all 12 emitters already carry lanes. This
is the residue that was genuinely broken.
## Tests — both with anti-vacuity controls
| control | result |
|---|---|
| revert `toTaskMoveLanes` | **2 of 4** core tests fail (the terminal
pair) |
| revert the scheduler union | the new engine test fails, **and only
it** (1 failed / 11 passed) |
| both restored | 4 passed, 12 passed |
The 2 core tests that pass either way are shape invariants asserted on
purpose (`complete` must stay first-match; a column-less IR returns
`undefined` rather than an invented lane) — flagging that so the control
isn't read as 4-of-4.
The pre-existing scheduler case emits **without** lanes, which no
production emitter does, so it exercises the sync fallback. The new one
emits `toTaskMoveLanes(ir)` — the shape that actually ships.
## Measured
| check | result |
|---|---|
| `@fusion/core` / `@fusion/engine` tsc | exit 0 / exit 0 |
| eslint | clean |
| `census --strict`, `check:fnxc-future-dates`, `check:changesets` |
exit 0 |
| every `TaskMoveLanes` consumer | 24 passed |
| `pnpm test:gate` | **exit 0 — 744 tests, up 12** |
## Census
No guard converted; this is a payload-shape fix. Backlog unchanged at
11, all deferred.
8661b739ff