hyperledger-labs / fabric-smart-client / 34119255568

86%

Build Type

push

github

Committed by web-flow

Commit Message

fix(comm): stop reusing the JSON decode target in readIncoming (#1746)

Both multiplexed readIncoming loops declared a single MultiplexedMessage
outside the loop and decoded every frame into it, then handed mm.Msg — a
[]byte aliasing that struct's field — to a consumer goroutine over a
channel.

Under Go 1.26 encoding/json allocated a fresh slice for every []byte
field, so the payload a consumer held was never written again. Go 1.27
makes encoding/json/v2 the default implementation, whose []byte path goes
through AppendDecode and reuses a non-nil destination's backing array.
The next ReadJSON then overwrites bytes a consumer is still reading:

	reused target -> held payload after 2nd decode: "BBBBBBBBBB"
	fresh target  -> held payload after 2nd decode: "AAAAAAAAAA"

That is silent message corruption on the wire, not only the data race
the detector reports in TestP2PLayerTestRound,
TestSessionsMultipleMessagesTestRound and TestConnections.

Declare mm per iteration so each decode starts from a nil slice and json
allocates a payload the reader owns. This also stops a field absent from
one frame from inheriting the previous frame's value.

Signed-off-by: Marcus Brandenburger <bur@zurich.ibm.com>

Coverage Stats

6 of 6 new or added lines in 1 file covered. (100.0%)

24 existing lines in 10 files now uncovered.

31322 of 36696 relevant lines covered (85.36%)

3303.57 hits per line