Change CheckPoint::push in favor of CheckPoint::insert

src/chain/cbf.rs

@@ -448,6 +448,7 @@ impl CbfChainSource {
 							reorganized.len(),
 							accepted.len(),
 						);
+						*state.latest_tip.lock().unwrap() = None;
 
 						// No height reset needed: skip heights are derived from
 						// BDK's checkpoint (on-chain) and LDK's best block
@@ -609,19 +610,18 @@ impl CbfChainSource {
 				},
 			};
 
-			// Build chain checkpoint extending from the wallet's current tip.
+			// Build chain checkpoint extending from the wallet's current tip,
+			// using `insert` (not `push`) so that reorgs are handled correctly.
+			// `insert` detects conflicting hashes and purges stale blocks,
+			// matching bdk-kyoto's approach in `UpdateBuilder::apply_chain_event`.
 			let mut cp = onchain_wallet.latest_checkpoint();
 			for (height, header) in sync_update.recent_history() {
-				if *height > cp.height() {
-					let block_id = BlockId { height: *height, hash: header.block_hash() };
-					cp = cp.push(block_id).unwrap_or_else(|old| old);
-				}
+				let block_id = BlockId { height: *height, hash: header.block_hash() };
+				cp = cp.insert(block_id);
 			}
 			let tip = sync_update.tip();
-			if tip.height > cp.height() {
-				let tip_block_id = BlockId { height: tip.height, hash: tip.hash };
-				cp = cp.push(tip_block_id).unwrap_or_else(|old| old);
-			}
+			let tip_block_id = BlockId { height: tip.height, hash: tip.hash };
+			cp = cp.insert(tip_block_id);
 
 			let update =
 				Update { last_active_indices: BTreeMap::new(), tx_update, chain: Some(cp) };
@@ -1396,4 +1396,71 @@ mod tests {
 			}
 		}
 	}
+
+	/// Test that checkpoint building from `recent_history` handles reorgs.
+	///
+	/// Scenario: wallet synced to height 103. A 3-block reorg replaces blocks
+	/// 101-103 with new ones (same tip height). `recent_history` returns
+	/// {94..=103} (last 10 blocks ending at tip) with new hashes at 101-103.
+	///
+	/// The checkpoint must reflect the reorged chain: new hashes at 101-103,
+	/// pre-reorg blocks at ≤100 preserved.
+	#[test]
+	fn checkpoint_building_handles_reorg() {
+		use bdk_chain::local_chain::LocalChain;
+		use bdk_chain::{BlockId, CheckPoint};
+		use bitcoin::BlockHash;
+		use std::collections::BTreeMap;
+
+		fn hash(seed: u32) -> BlockHash {
+			use bitcoin::hashes::{sha256d, Hash, HashEngine};
+			let mut engine = sha256d::Hash::engine();
+			engine.input(&seed.to_le_bytes());
+			BlockHash::from_raw_hash(sha256d::Hash::from_engine(engine))
+		}
+
+		let genesis = BlockId { height: 0, hash: hash(0) };
+
+		// Wallet checkpoint: 0 → 100 → 101 → 102 → 103
+		let wallet_cp = CheckPoint::from_block_ids([
+			genesis,
+			BlockId { height: 100, hash: hash(100) },
+			BlockId { height: 101, hash: hash(101) },
+			BlockId { height: 102, hash: hash(102) },
+			BlockId { height: 103, hash: hash(103) },
+		])
+		.unwrap();
+
+		// recent_history after reorg: 94-103, heights 101-103 have NEW hashes.
+		let recent_history: BTreeMap<u32, BlockHash> = (94..=103)
+			.map(|h| {
+				let seed = if (101..=103).contains(&h) { h + 1000 } else { h };
+				(h, hash(seed))
+			})
+			.collect();
+
+		// Build checkpoint using the same logic as sync_onchain_wallet.
+		let mut cp = wallet_cp;
+		for (height, block_hash) in &recent_history {
+			let block_id = BlockId { height: *height, hash: *block_hash };
+			cp = cp.insert(block_id);
+		}
+
+		// Reorged blocks must have the NEW hashes.
+		assert_eq!(cp.height(), 103);
+		assert_eq!(
+			cp.get(101).expect("height 101 must exist").hash(),
+			hash(1101),
+			"block 101 must have the reorged hash"
+		);
+		assert_eq!(cp.get(102).expect("height 102 must exist").hash(), hash(1102));
+		assert_eq!(cp.get(103).expect("height 103 must exist").hash(), hash(1103));
+
+		// Pre-reorg blocks are preserved.
+		assert_eq!(cp.get(100).expect("height 100 must exist").hash(), hash(100));
+
+		// The checkpoint must connect cleanly to a LocalChain.
+		let (mut chain, _) = LocalChain::from_genesis_hash(genesis.hash);
+		chain.apply_update(cp).expect("checkpoint must connect to chain");
+	}
 }

tests/integration_tests_rust.rs

@@ -23,9 +23,9 @@ use common::{
 	expect_payment_successful_event, expect_splice_pending_event, generate_blocks_and_wait,
 	generate_listening_addresses, open_channel, open_channel_push_amt, open_channel_with_all,
 	premine_and_distribute_funds, premine_blocks, prepare_rbf, random_chain_source, random_config,
-	random_listening_addresses, setup_bitcoind_and_electrsd, setup_builder, setup_node,
-	setup_two_nodes, skip_if_cbf, splice_in_with_all, wait_for_cbf_sync, wait_for_tx,
-	TestChainSource, TestStoreType, TestSyncStore,
+	setup_bitcoind_and_electrsd, setup_builder, setup_node, setup_two_nodes, skip_if_cbf,
+	splice_in_with_all, wait_for_cbf_sync, wait_for_tx, TestChainSource, TestStoreType,
+	TestSyncStore,
 };
 use electrsd::corepc_node::Node as BitcoinD;
 use electrsd::ElectrsD;