FA-74927 / CRDT convergence / Member archive

LWW element set with add bias: a delayed local add lowers the stored timestamp · case 02

An old add delivered late makes a newer element lose to an intermediate remove.

Member previewVariant 2 · 3 implementations · 9 checks per implementation

Case contract

Each replica keeps add and remove timestamp maps. ["add"|"rem", r, e, t] records t when it exceeds the stored timestamp. ["merge", s, d] folds both maps of s into d by maximum. An element is a member when it has an add timestamp that is greater than or equal to its remove timestamp (ties favour add). Return sorted members per replica.

Why this case matters

LWW element sets resolve add/remove races by timestamp and need a deterministic tie bias.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
out-of-order local add keeps the maximum	`[[], []]`	`[["w"], []]`	Failed

MEMBER ARCHIVE

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