Flip WIRE snapshot magic for hex-dump readability#309
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The magic byteswap was extracted to PR #309 targeting feature/kv-secondary-primary-id. This branch goes back to master's reference snapshot files and the original 0x57495245 magic; reference files will be regenerated on top of #309 when it lands. Reverted: - libraries/chain/include/sysio/chain/snapshot.hpp - magic restored to 0x57495245 - unittests/snapshots/{blocks.log,snap_v1.bin.gz,snap_v1.bin.json.gz, snap_v1.json.gz} - reverted to master - unittests/test-data/consensus_blockchain/snapshot - reverted to master - tests/sysio_util_snapshot_info_test.py - head_block_id reverted; flush fix retained
huangminghuang
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May 7, 2026
Reverse the on-disk byte order of the snapshot v1 header magic so a hex dump of a snapshot file reads 'W','I','R','E' instead of 'E','R','I','W'. Stored little-endian as 0x45524957 -> bytes on disk 57 49 52 45. Pre-launch; no backward compatibility. Snapshots written with the old magic cannot be read after this change.
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The snapshot magic flip changes the on-disk header bytes. Regenerated
via:
unit_test --run_test='snapshot_part2_tests/*' -- --sys-vm \
--save-snapshot --generate-snapshot-log
head_block_id in sysio_util_snapshot_info_test.py updated to match the
new fixture; blocks.log / blocks.index regenerated as a byproduct of
--generate-snapshot-log.
The snapshot regen run on this branch also drifted the action_mroot
that savanna_misc_tests/verify_block_compatibitity compares against.
Regenerated via:
unit_test -t "savanna_misc_tests/verify_block_compatibitity" \
-- --sys-vm --save-blockchain
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Summary
Reverses the on-disk byte order of the snapshot v1 header magic so a hex dump of a snapshot file reads
W,I,R,Einstead ofE,R,I,W.The value is stored little-endian as a
uint32_t:0x57495245-> bytes on disk45 52 49 57("ERIW")0x45524957-> bytes on disk57 49 52 45("WIRE")Compatibility
No backward compatibility. Snapshots written with the old magic cannot be read after this change. Pre-launch, so the break is acceptable.