## A green case that stopped testing what its name says
#3226 fixed a red `main` correctly: `fileWithGuards()` now returns
`null` at zero backlog, and with nothing to inflate there is no rise to
manufacture. Asserting `totals.column === 0` and returning is the honest
response.
What went unrecorded is the cost. At zero, these two cases:
- *"exits 0 and REWRITES the baseline under `--update-baseline`, even
when the count rose"*
- *"exits 1 and LEAVES the baseline alone on a rise without
`--update-baseline`"*
no longer exercise the CLI's ordering or exit codes. They assert the
backlog is empty and return. **If the write-before-exit ordering
regressed — the exact bug those cases were written for — both would
still pass.**
That matters more than it would elsewhere, because **zero is not a state
to wait out.** It is this program's terminal state: the backlog went 126
→ 0 and is meant to stay there. So the vacuity is permanent, not
transitional.
This file already legislates against precisely this, two hundred lines
down:
> `/* Anti-vacuity: an empty exclusion list would make the assertion
below trivially true. */`
## What this PR does
Adds a comment on `fileWithGuards()` recording (a) which cases go
vacuous at zero and why, (b) that zero is terminal so it will not
resolve itself, and (c) the durable fix.
**Comment only. No behaviour change — suite stays 53/53.**
## The durable fix, recorded rather than done
Point the scan at a synthetic tree so the fixture stops being a function
of the real backlog — the same seam `FUSION_CENSUS_BASELINE_PATH`
already provides for the baseline, applied to the file list.
It needs one CLI correction to work, and that is a genuine bug in my own
code regardless of this suite: `triageFindings` and the sync-resolver
check read files via `join(REPO_ROOT, f.file)`, where `REPO_ROOT` is
derived from the **script's** location. An overridden file list
therefore changes which paths are *listed* without changing where they
are *read from*, and every read misses with `ENOENT`.
I verified that approach works (a three-file fixture yields a stable `1
backlog / 1 deliberate / 1 sync-resolved`) and got two of the six
failing cases green with it, then stopped rather than keep guessing in a
file being actively revised. Left as a comment so whoever takes it does
not re-derive the diagnosis.
## Why this is worth a PR at all
This program's recurring failure is instruments that report green while
measuring nothing — an inert conversion the census scored as a win, a
ratchet wired to nothing, a gate that could not fail. A test asserting
`0 === 0` under a name promising ordering coverage is the same shape at
the test layer. The suite cannot be fixed in this PR without re-opening
work someone else owns, but it can at least stop being silent about it.
## Census before / after
```
before: COLUMN guards (the backlog): 0
after: COLUMN guards (the backlog): 0
```
## Verification
`test:gate` exit 0 · `lifecycle-column-census.test.ts` **53 passed** ·
`fnxc-future-dates`, `lifecycle-columns`, `inert-sync-lanes`,
`quarantine-ledger`, `inert-flag-seams`, `lane-wiring`,
`sql-column-literals` — all exit 0.
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