complete_multipart_upload built the object-level checksum record from a
ChecksumType copied before the MULTIPART / INCLUDES_MULTIPART flags were
merged in. ChecksumType::merge takes &mut self, so the merge updated the
local variable while the copy already inside the Checksum struct stayed
behind. The composite branch rebuilt the Checksum from the merged type
and was unaffected; the full-object branch never rebuilt it, so those
flags never reached disk.
rustfs_rio::read_checksums only sets its multipart flag and only emits
the "x-amz-checksum-type" = "FULL_OBJECT" entry inside its MULTIPART
branch, so a full-object multipart object read back as non-multipart with
no type entry, and GetObject and HeadObject answered with no
x-amz-checksum-type header at all where AWS returns FULL_OBJECT.
Hand the full-object branch the merged type instead of rebuilding the
Checksum: the value must stay the running merge produced by add_part,
because hashing the concatenated part digests would yield the COMPOSITE
value, a different number than the one the client sent. The serialization
now lives in multipart_object_checksum_record so both shapes are covered
by unit tests.
Records written by earlier builds carry the bare algorithm type with no
MULTIPART flags and no trailing part block; they keep reading back to the
same checksum value, and the FULL_OBJECT reader arm predates this change
so older peers parse the new record shape correctly too.
Found while root-causing rustfs#6825.
唐小鸭
1c56410364