FA-097 / Distributed coordination / Member archive

Election votes prefer a longer but older log · case 02

A candidate with more entries from an older term receives a vote over the voter's newer history.

Member previewVariant 2 · 3 implementations · 7 checks per implementation

Case contract

State is [current term,voted candidate or None], local log is [last term,last index], and requests are [election term,candidate,last log term,last index]. Newer terms clear the vote even if the candidate is rejected. Grant only in current term to an up-to-date log and an unclaimed or same vote. Return [term,voted candidate,grant decisions]. This is a voting-rule model, not a consensus implementation.

Why this case matters

Models two interacting durable election invariants: freshness by log term and one candidate per election term, including term advancement on rejected requests.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
longer old-term log rejected	`[12, "a", [true]]`	`[12, null, [false]]`	Failed

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