A review of the P13-S3 fix caught the reducer's comment overclaiming. It said
the coupling "cannot mis-fire on an unrelated operation" because
ModifyIdentifiedPitch never writes the spelling set. That is true of the
OPERATION and irrelevant to the UNIT: the coupling is keyed on the pitch, and
on which keys the TRANSACTION wrote. A transaction whose members write the two
halves separately couples exactly the same way.
The editor's "move note" is precisely that -- ModifyIdentifiedPitch for the
value plus RespellPitch for the spelling set, in one transaction. Measured:
no later respell, BestEffort -> Applied, pitch restored to C4
later respell, BestEffort -> Applied, pitch STAYS D4, later E stands
later respell, StrictInverse -> Conflicted, pitch stays D4
The middle row is the coupling firing on a non-transpose pair, and it is
correct: restoring the pitch to C4 while the engraved spelling reads E --
authored against the moved pitch -- is exactly the stale-notehead defect the
coupling exists to prevent. Musically, undoing half of "move this note and
respell it" is not a smaller undo, it is a wrong score.
So the breadth is stated rather than left to be inferred.
req:opcat:spelling-set-chain now says the unit is keyed on the pitch and on the
transaction's writes, names the move-and-respell case, and notes that a
transaction writing only one of the two keys is unaffected -- an unwritten key
yields no supersession, which is the narrow claim the old comment should have
made.
Three regressions: full undo when nothing supersedes (guards against
OVER-coupling), best-effort skipping the pair when a later respell supersedes,
and strict undo conflicting. Mutation-verified by removing the coupling: only
the middle test fails, restoring the pitch to C4 with its spelling still
reading E, while the other two stay green -- they lock different properties.
Gate: fmt clean, clippy 0, 30 targets / 1001 passed / 0 failed, docs 0 under
-D warnings, conformance 8/8, zero golden churn, canonical-base digest unmoved.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Levi Neuwirth
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