Fix Across in-transit check exceeding RPC max block range - #977

check_fill_on_chain queried logs from block 0x0 to latest, causing RPC failures on chains like Base where providers enforce a 100,000-block range limit (-32602).

Changes

• across/mod.rs — Added FILL_LOOKBACK_BLOCKS = 100_000 constant
• across/provider.rs — Fetch the destination chain's current block before querying logs; use current_block - 100_000 as fromBlock instead of genesis

let current_block = client.get_latest_block().await...;
let from_block = current_block.saturating_sub(FILL_LOOKBACK_BLOCKS);
let from_block_hex = format!("0x{:x}", from_block);

let logs = client.get_logs(deployment.spoke_pool, &topics, &from_block_hex, "latest").await...;

100,000 blocks safely covers the 6-hour fill timeout (DEFAULT_FILL_TIMEOUT) on the fastest supported chain (Arbitrum at ~0.25 s/block ≈ 7 hours of coverage).

🔒 GitHub Advanced Security automatically protects Copilot coding agent pull requests. You can protect all pull requests by enabling Advanced Security for your repositories. Learn more about Advanced Security.