F3: an override drifts exactly as the same member would on a plain record. A
slot the type dropped is ignored and reported by the store's schema resolution
(LastSchemaMigrationReports), the one surface a plain record uses; a value that
no longer decodes refuses the load, naming the variant and member. The second
report surface (VariantMigrationReports, the per-variant report map, the
catalog slot-name plumbing) is deleted.
F4: an override for a slot the type does not have, or a value that does not
decode as the member, is refused at write. Drift is for type changes after the
fact, not for bad writes. F5: two overrides of one slot are refused.
F2: a variant that shares an indexed value with another record is refused,
naming both keys and the index (the R6 rule extended to [CultIndex]); plain
record duplicate handling is unchanged.
F7: a flatten now resolves against the same batch, so a base edited in that
batch is in the flattened record; and the directory store refuses to load a
variant page as it refuses to write one.
The C1 vector's big variant now overrides its indexed code, as the unique-index
rule requires.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
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