glenn schrooyenandClaude Opus 5
f6d7bfcb04
checks / unit (pull_request) Successful in 7m38s
⚠️ THE CONTROL I WROTE LAST ROUND WAS INERT, AND REVIEW MEASURED IT. M12 ran its
mutant over `state-legacy.json` and the findings diff against the UNMUTATED tree
was EMPTY. It "passed" because that fixture's STAGED leg is already exit 1 on
pre-existing litter, and `"migrated unit/shed/" not in out` was trivially true
because a pre-DEV-02 FLAT store has no shed latch to lose - after migration only
the FIRST roster entry is ever latched.
The decisive measurement is the one it could not make: reverting the
`vanished_unit not in after.units` narrowing - restoring exactly the rule that
hides a real latch loss - left 28/28 GREEN.
⚠️ SO IT WAS HABIT 4 WEARING THE CLOTHES OF ITS OWN FIX, AND WORSE THAN THE
"NO CONTROL" IT REPLACED, because it reads as checked. That is this commit's
own argument about the M3 mis-citation, turned on the thing I wrote to answer it.
⭐ THE FIXTURE CAME FIRST THIS TIME. `state-both-latched.json` is a store at
SCHEMA_VERSION with `unit/garage/*` AND `unit/shed/*` both latched by ONE site
event, so the reasons match too - the arrangement in which same-value
suppression is most dangerous, and the one no existing fixture could produce.
M12's mutant then makes ONE roster unit's latch key VANISH while its sibling's
survives at the same value:
shipped tree, both-latched fixture exit 0, no findings
one unit's latch key deleted exit 1, ADDS
VANISHED STORE KEY unit/shed/sign_tripped
narrowing reverted ⚠️ RED (was 28/28 green)
And it asserts the PRECONDITION - the fixture is clean on the shipped tree -
plus that the mutation ADDS findings rather than coinciding with ones the
fixture already had. An empty diff there is exactly what made the last draft
inert, and nothing said so.
⭐ AND THE MOVE IS NOW INJECTIVE, which is the narrower hole review found still
open. `moved_to` is "any machine-read key with the same bare name and the same
value", and `DEFAULTS["sign_tripped"] is False` means `True` is the ONLY
non-default value a latch can hold - so N vanished keys could all claim the SAME
destination, by construction rather than by coincidence. Measured on a rename
carrying `inverter-a` -> `garage` correctly while DROPPING `inverter-b` -> `shed`:
migrated unit/inverter-a/sign_tripped = True -> unit/garage/sign_tripped
migrated unit/inverter-b/sign_tripped = True -> unit/garage/sign_tripped
Zero store-key findings, on a run where `shed` came up UNLATCHED. Two keys
cannot both have become one key. `diff()` claims each destination once.
⚠️ AND THE CHECK FOR IT IS ANCHORED TO A RUN THAT ACTUALLY PRODUCES MIGRATED
LINES. A dedicated mutant was written first and asserted over an EMPTY list -
vacuous, passing, indistinguishable from working, the same defect twice in one
sitting. These fixtures cannot produce two claimants (`migrate_unit_keys()`
moves FLAT keys only, so one flat latch yields one migration), so rather than
build a fiction to grade, injectivity is asserted over part 5's real migrations,
with a PRECONDITION that there are at least two of them. THE TWO-CLAIMANT
ARRANGEMENT IS A STATED RESIDUAL: bounded in `diff()` by construction, not
measured end-to-end.
Finding 4, and my correction to it was also wrong. The comment cited "line 315"
and "two hundred lines below"; the fix I wrote said "~54 lines down", which was
review's distance to the WRONG line, carried to a new referent without
re-measuring - inside the sentence apologising for a wrong number. Recomputed at
5e382f5: 327-261 = 66, 327-252 = 75, and 54 was neither. There is no distance
now, because a distance is a coordinate and the sentence already names the thing.
And the residual gains its second half, which review noticed and I had not: the
reason re-armed from is the FLAT mirror, carrying whatever tripped LAST, so this
path can print one inverter's evidence under another's name. The latch is right
and the explanation may not be. `test_maintenance.py`'s check that the reason is
not the removed unit's is guaranteed by that fixture's flat string, NOT by the
code, and now says so.
28/28 files pass.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU