[heifner]

Each sysio.synd returns row now records sent_epoch, the depot epoch of the outbound envelope that carried its DESYNDICATE_LIQ. A later cleanup can expire a row once the outpost has consumed that envelope: once sysio.msgch's outpcons epoch for the outpost reaches sent_epoch. An outpost emits its envelope for an epoch only after accepting the depot's, which is the rule buildenv already uses to drop consumed outbound envelopes.

Behavior

• sent_epoch is 0 while the attestation waits in the outbound queue. An envelope carries at most 64 attestations and the queue holds up to 512, so a row can ship several epochs after it was queued. The epoch at desyndicate time cannot tell a cleanup which envelope carried it.
• sysio.msgch::buildenv reads the request id of each DESYNDICATE_LIQ it ships and sends one inline sysio.synd::retsent(chain_code, epoch_index, request_ids) per envelope. An envelope without a DESYNDICATE_LIQ sends nothing. Bytes that do not decode, or carry request id 0, are skipped.
• retsent (authority sysio.msgch) runs inside sysio.epoch::advance and never aborts. It drops, with a diagnostic, an id with no row (governance already resolved it), a row of another outpost, and a row already stamped.
• finishreturn and refundreturn are unchanged.
• Only sysio.synd and sysio.msgch change wasm and ABI.

Coordination

• ABI change: return_row.sent_epoch and the retsent action. wire-libraries-ts #151 regenerates SysioContractTypes.ts. wire-tools-ts only reads returns rows and needs no change.
• Fix reentrant desyndication custody attestations (WIRE-441) #756 also edits sysio.synd. Whichever merges second rebases and rebuilds the wasm and ABI.
• e2e: run 42750978502 with BRANCH_WIRE_SYSIO and BRANCH_WIRE_LIBRARIES_TS on feature/synd-return-epoch and BRANCH_WIRE_TOOLS_TS=fix/wire-441 (wire-tools-ts New default config/data location. Use app for kiod and ethereum_client_rpc_tool. #181, which the Solana AuthEx bootstrap needs on current master)

[huangminghuang]

Reviewed the current diff and relevant contract and epoch context using the open code review workflow. No actionable findings given the confirmed prelaunch context.

Validation: all four new tests passed, with 392 assertions.

[huangminghuang]

Re-reviewed the complete current diff at e2edfaf after the merge of master and dispatcher rebuild, using the open code review workflow. No actionable findings in the confirmed prelaunch context. The source changes, ABI, and added tests match the previously reviewed version; both affected WASMs were rebuilt.

Validation: all 153 syndication and message-channel contract tests passed, with 14,024 assertions, against the current committed contract artifacts using the existing host test libraries. git diff --check passed. GitHub's Linux amd64 build and tests workflow is still queued.