September 13, 2026 — History sync admission policy

Features

Generic history-sync admission policy (#1501) A new HistorySyncAdmission trait, re-exported from the crate root, gates inbound history-sync notifications before the client starts any history-sync activity. The policy receives a small HistorySyncMetadata view — sync type, chunk order, progress, sender-declared file length, inline payload length, and any peer-data-request session id — and returns Accept or RejectAndAcknowledge. A rejected notification sends a hist_sync receipt and is never enqueued. Register on either builder:

use whatsapp_rust::{HistorySyncAdmission, HistorySyncDecision, HistorySyncMetadata};

struct RejectPeerDataResponses;

impl HistorySyncAdmission for RejectPeerDataResponses {
    fn decide(&self, metadata: &HistorySyncMetadata<'_>) -> HistorySyncDecision {
        if metadata.peer_data_request_session_id.is_some() {
            HistorySyncDecision::RejectAndAcknowledge
        } else {
            HistorySyncDecision::Accept
        }
    }
}

Bot::builder()
    .with_history_sync_admission(RejectPeerDataResponses)
    // ...

Leaving the policy unset keeps the default behavior at zero cost — the receive path only checks that the optional policy is None. The skip_history_sync toggle still takes precedence: when it is on, the client sends the receipt and never consults the policy. Device registration and require_full_sync are unchanged. See History Sync Admission Hook for the full contract, the metadata field reference, and worked examples.

​Features

Features