FA-74959 / CRDT convergence / Member archive

Multi-value register: equal version vectors dominate each other · case 04

Merging a replica with an identical copy of its state erases the register value.

Member previewVariant 4 · 3 implementations · 9 checks per implementation

Case contract

Each replica holds siblings [value, version vector]. ["write", r, v] builds the pointwise maximum of all current sibling vectors, increments r's entry, and replaces all siblings with [v, vector]. ["merge", s, d] pools both sibling lists, drops siblings strictly dominated by another pooled sibling, and keeps one copy per identical vector. Return sorted values per replica.

Why this case matters

Multi-value registers expose concurrent writes as siblings instead of silently discarding one.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
concurrent writes become siblings	`[[], [], []]`	`[["x", "y4"], ["x", "y4"], []]`	Failed

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