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A persisted partial-response cache record keeps byte coverage and revision metadata intact: persisted generations retain their high byte · case 04

A persisted partial-response cache record keeps byte coverage and revision metadata intact: persisted generations retain their high byte.

Member previewVariant 4 · 3 implementations · 10 checks per implementation

Case contract

Decode this stipulated local binary cache envelope: magic RG, version1, flags0, two-byte big-endian generation, two-byte big-endian complete length, one-byte fragment count, then fragments [two-byte big-endian offset,one-byte count,ASCII payload], followed by one checksum byte equal to sum of preceding bytes modulo256. Reject malformed envelopes, bytes outside0..255, trailing bytes, overlapping fragment ownership, or spans outside complete length. Return [generation,total,[[offset,payload],...]]. This is an invented bounded persistence format, not a public protocol.

Why this case matters

Range responses combine representation identity, conditional requests, framing, and partial-object state.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
revision-byte-order fixture 0	`[1025, 258, [[0, "ab"], [256, "cd"]]]`	`[260, 258, [[0, "ab"], [256, "cd"]]]`	Failed

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