* test(wal): pin v1 entry encoding to a Clang-written fixture
store_block_entry_clang_v1.bin is one StoreBlock entry serialized by the
current wal_entry.cpp built with Clang 21, which zero-fills the 4 bytes of
trailing Header padding. The new cases decode and verify it, re-encode the
same logical entry and require identical bytes, and round-trip fresh
entries through serialize/deserialize/verifyChecksum.
GCC 16 leaves that padding uninitialized in stableHeaderBytes(), so these
cases fail there.
Signed-off-by: trvon <me@trevon.dev>
* fix(wal): encode entry header field by field, never via padding
stableHeaderBytes() built the checksummed header with `Header stable{}`
plus member assignments and then memcpy'd sizeof(Header) bytes. That is
aggregate initialization, so the 4 bytes of trailing padding (offsets
44..47) are not guaranteed to be zero. Clang 21 memsets the object first;
GCC 16 at -O0 stores only the members, so stack garbage reached both the
serialized entry and the CRC, and verifyChecksum() failed on GCC builds.
Encode and decode the header field by field into a zero-filled 48-byte
array at the existing offsets, with static_asserts pinning every offset
and size. The checksum is CRC32 over that canonical encoding plus the
payload, which is exactly what Clang builds have always written, so their
WAL files verify unchanged. deserialize() also accepts an entry whose CRC
covers nonzero padding as stored on disk (written by earlier GCC builds)
and normalizes its in-memory checksum. WALFile and WALManager recovery
read headers through the new WALEntry::decodeHeader().
TransactionData (uint64 + uint32) has 4 bytes of trailing padding and was
copied whole into the payload, relying on the same unguaranteed zeroing
(GCC 16 and Clang 21 happen to zero it today); it is now encoded field by
field too. The remaining payload structs are padding-free, which
appendObjectBytes/readObject now enforce with
has_unique_object_representations_v.
Signed-off-by: trvon <me@trevon.dev>
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Signed-off-by: trvon <me@trevon.dev>
8000226a4c