fix(wallet)!: make TxBuilder::current_height type-safe via absolute::Height

Author: none34829

src/wallet/mod.rs

@@ -1305,7 +1305,11 @@ impl Wallet {
             // If they didn't tell us the current height, we assume it's the latest sync height.
             None => {
                 let tip_height = self.chain.tip().height();
-                absolute::LockTime::from_height(tip_height).expect("invalid height")
+                // If the local chain tip height is not a valid block height for a locktime,
+                // that's an invariant violation in `LocalChain` (block heights are
+                // always below the locktime threshold) and should be addressed upstream.
+                absolute::LockTime::from_height(tip_height)
+                    .expect("LocalChain tip height should be a valid block height")
             }
             Some(h) => h,
         };

src/wallet/tx_builder.rs

@@ -649,9 +649,12 @@ impl<'a, Cs> TxBuilder<'a, Cs> {
     ///    them using [`TxBuilder::add_utxos`].
     ///
     /// In both cases, if you don't provide a current height, we use the last sync height.
-    pub fn current_height(&mut self, height: u32) -> &mut Self {
-        self.params.current_height =
-            Some(absolute::LockTime::from_height(height).expect("Invalid height"));
+    ///
+    /// This method takes an [`absolute::Height`], which is guaranteed by the type system to
+    /// be a valid block height for a locktime (below 500_000_000). Callers can construct one
+    /// with [`absolute::Height::from_consensus`].
+    pub fn current_height(&mut self, height: absolute::Height) -> &mut Self {
+        self.params.current_height = Some(absolute::LockTime::from(height));
         self
     }
 

tests/wallet.rs

@@ -298,7 +298,7 @@ fn test_create_tx_custom_locktime() {
     let mut builder = wallet.build_tx();
     builder
         .add_recipient(addr.script_pubkey(), Amount::from_sat(25_000))
-        .current_height(630_001)
+        .current_height(absolute::Height::from_consensus(630_001).unwrap())
         .nlocktime(absolute::LockTime::from_height(630_000).unwrap());
     let psbt = builder.finish().unwrap();
 
@@ -2537,7 +2537,7 @@ fn test_spend_coinbase() {
     let mut builder = wallet.build_tx();
     builder
         .add_recipient(addr.script_pubkey(), balance.immature / 2)
-        .current_height(confirmation_height);
+        .current_height(absolute::Height::from_consensus(confirmation_height).unwrap());
     assert!(matches!(
         builder.finish(),
         Err(CreateTxError::CoinSelection(
@@ -2552,7 +2552,7 @@ fn test_spend_coinbase() {
     let mut builder = wallet.build_tx();
     builder
         .add_recipient(addr.script_pubkey(), balance.immature / 2)
-        .current_height(not_yet_mature_time);
+        .current_height(absolute::Height::from_consensus(not_yet_mature_time).unwrap());
     assert_matches!(
         builder.finish(),
         Err(CreateTxError::CoinSelection(
@@ -2583,7 +2583,7 @@ fn test_spend_coinbase() {
     let mut builder = wallet.build_tx();
     builder
         .add_recipient(addr.script_pubkey(), balance.confirmed / 2)
-        .current_height(maturity_time);
+        .current_height(absolute::Height::from_consensus(maturity_time).unwrap());
     builder.finish().unwrap();
 }