Two safe-integer timestamps can differ by more than 2^53-1 (e.g.
MIN_SAFE_INTEGER to MAX_SAFE_INTEGER-1), so the dt subtraction rounds
and the packed row decodes to a timestamp one off the original --
violating the codec's lossless contract. Unreachable from a real clock
(the gap needs ~285k years) but reachable from hand-written fixtures,
and the decoder accepts hand-written rows.
continues() now refuses to extend a run across such a gap (the check is
exact both ways: an in-range true gap subtracts without rounding and
passes; an out-of-range one rounds to an out-of-range value and fails),
splitting the run instead -- whitelist philosophy, compression lost,
data never. The decoder tightens to match the encoder's image: time0
and dt must be safe integers, and reconstructed member seqs/times must
stay in safe range, so float reconstruction is exact wherever
validation passes.
The round-trip property now draws times from the full safe-integer
range (it previously generated only small gaps, which is how this
escaped); the bot's counterexample is pinned as an example test.
Found by ds-review-bot on #338.
kingwl
8f5c592b9f