Fix the tracking of immature coinbase deposits

doc/API.md

@@ -96,6 +96,7 @@ This command does not take any parameter for now.
 | `outpoint`     | string        | Transaction id and output index of this coin.                                                                      |
 | `block_height` | int or null   | Block height the transaction was confirmed at, or `null`.                                                          |
 | `spend_info`   | object        | Information about the transaction spending this coin. See [Spending transaction info](#spending_transaction_info). |
+| `is_immature`  | bool          | Whether this coin was created by a coinbase transaction that is still immature.                                    |
 
 
 ##### Spending transaction info

src/bitcoin/d/mod.rs

@@ -1105,6 +1105,7 @@ pub struct LSBlockEntry {
     pub block_height: Option<i32>,
     pub address: bitcoin::Address<address::NetworkUnchecked>,
     pub parent_descs: Vec<descriptor::Descriptor<descriptor::DescriptorPublicKey>>,
+    pub is_immature: bool,
 }
 
 impl From<&Json> for LSBlockEntry {
@@ -1150,12 +1151,19 @@ impl From<&Json> for LSBlockEntry {
             })
             .expect("bitcoind can't give invalid descriptors");
 
+        let is_immature = json
+            .get("category")
+            .and_then(Json::as_str)
+            .expect("must be present")
+            == "immature";
+
         LSBlockEntry {
             outpoint,
             amount,
             block_height,
             address,
             parent_descs,
+            is_immature,
         }
     }
 }
@@ -1183,7 +1191,7 @@ impl From<Json> for LSBlockRes {
                     .get("category")
                     .and_then(Json::as_str)
                     .expect("must be present");
-                if category == "receive" || category == "generate" {
+                if ["receive", "generate", "immature"].contains(&category) {
                     let lsb_entry: LSBlockEntry = j.into();
                     Some(lsb_entry)
                 } else {
@@ -1201,6 +1209,8 @@ pub struct GetTxRes {
     pub conflicting_txs: Vec<bitcoin::Txid>,
     pub block: Option<Block>,
     pub tx: bitcoin::Transaction,
+    pub is_coinbase: bool,
+    pub confirmations: i32,
 }
 
 impl From<Json> for GetTxRes {
@@ -1238,10 +1248,21 @@ impl From<Json> for GetTxRes {
         let bytes = Vec::from_hex(hex).expect("bitcoind returned a wrong transaction format");
         let tx: bitcoin::Transaction = bitcoin::consensus::encode::deserialize(&bytes)
             .expect("bitcoind returned a wrong transaction format");
+        let is_coinbase = json
+            .get("generated")
+            .and_then(Json::as_bool)
+            .unwrap_or(false);
+        let confirmations = json
+            .get("confirmations")
+            .and_then(Json::as_i64)
+            .expect("Must be present in the response") as i32;
+
         GetTxRes {
             conflicting_txs: conflicting_txs.unwrap_or_default(),
             block,
             tx,
+            is_coinbase,
+            confirmations,
         }
     }
 }

src/bitcoin/mod.rs

@@ -14,6 +14,8 @@ use std::{fmt, sync};
 
 use miniscript::bitcoin::{self, address};
 
+const COINBASE_MATURITY: i32 = 100;
+
 /// Information about a block
 #[derive(Debug, Clone, Eq, PartialEq, Copy)]
 pub struct Block {
@@ -146,6 +148,7 @@ impl BitcoinInterface for d::BitcoinD {
                     block_height,
                     address,
                     parent_descs,
+                    is_immature,
                 } = entry;
                 if parent_descs
                     .iter()
@@ -156,6 +159,7 @@ impl BitcoinInterface for d::BitcoinD {
                         amount,
                         block_height,
                         address,
+                        is_immature,
                     })
                 } else {
                     None
@@ -184,6 +188,11 @@ impl BitcoinInterface for d::BitcoinD {
 
             // If the transaction was confirmed, mark the coin as such.
             if let Some(block) = res.block {
+                // Do not mark immature coinbase deposits as confirmed until they become mature.
+                if res.is_coinbase && res.confirmations < COINBASE_MATURITY {
+                    log::debug!("Coin at '{}' comes from an immature coinbase transaction with {} confirmations. Not marking it as confirmed for now.", op, res.confirmations);
+                    continue;
+                }
                 confirmed.push((*op, block.height, block.time));
                 continue;
             }
@@ -409,4 +418,5 @@ pub struct UTxO {
     pub amount: bitcoin::Amount,
     pub block_height: Option<i32>,
     pub address: bitcoin::Address<address::NetworkUnchecked>,
+    pub is_immature: bool,
 }

src/bitcoin/poller/looper.rs

@@ -24,6 +24,8 @@ struct UpdatedCoins {
 // or spent.
 // NOTE: A coin may be updated multiple times at once. That is, a coin may be received, confirmed,
 // and spent in a single poll.
+// NOTE: Coinbase transaction deposits are very much an afterthought here. We treat them as
+// unconfirmed until the CB tx matures.
 fn update_coins(
     bit: &impl BitcoinInterface,
     db_conn: &mut Box<dyn DatabaseConnection>,
@@ -42,6 +44,7 @@ fn update_coins(
             outpoint,
             amount,
             address,
+            is_immature,
             ..
         } = utxo;
         // We can only really treat them if we know the derivation index that was used.
@@ -66,6 +69,7 @@ fn update_coins(
             if !curr_coins.contains_key(&utxo.outpoint) {
                 let coin = Coin {
                     outpoint,
+                    is_immature,
                     amount,
                     derivation_index,
                     is_change,

src/commands/mod.rs

@@ -50,6 +50,7 @@ pub enum CommandError {
     InvalidFeerate(/* sats/vb */ u64),
     UnknownOutpoint(bitcoin::OutPoint),
     AlreadySpent(bitcoin::OutPoint),
+    ImmatureCoinbase(bitcoin::OutPoint),
     Address(bitcoin::address::Error),
     InvalidOutputValue(bitcoin::Amount),
     InsufficientFunds(
@@ -77,6 +78,7 @@ impl fmt::Display for CommandError {
             Self::NoOutpoint => write!(f, "No provided outpoint. Need at least one."),
             Self::InvalidFeerate(sats_vb) => write!(f, "Invalid feerate: {} sats/vb.", sats_vb),
             Self::AlreadySpent(op) => write!(f, "Coin at '{}' is already spent.", op),
+            Self::ImmatureCoinbase(op) => write!(f, "Coin at '{}' is from an immature coinbase transaction.", op),
             Self::UnknownOutpoint(op) => write!(f, "Unknown outpoint '{}'.", op),
             Self::Address(e) => write!(
                 f,
@@ -298,6 +300,7 @@ impl DaemonControl {
                     block_info,
                     spend_txid,
                     spend_block,
+                    is_immature,
                     ..
                 } = coin;
                 let spend_info = spend_txid.map(|txid| LCSpendInfo {
@@ -310,6 +313,7 @@ impl DaemonControl {
                     outpoint,
                     block_height,
                     spend_info,
+                    is_immature,
                 }
             })
             .collect();
@@ -349,6 +353,10 @@ impl DaemonControl {
             if coin.is_spent() {
                 return Err(CommandError::AlreadySpent(*op));
             }
+            if coin.is_immature {
+                return Err(CommandError::ImmatureCoinbase(*op));
+            }
+
             // Fetch the transaction that created it if necessary
             if !spent_txs.contains_key(op) {
                 let tx = self
@@ -840,6 +848,8 @@ pub struct ListCoinsEntry {
     pub block_height: Option<i32>,
     /// Information about the transaction spending this coin.
     pub spend_info: Option<LCSpendInfo>,
+    /// Whether this coin was created by a coinbase transaction that is still immature.
+    pub is_immature: bool,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -976,6 +986,7 @@ mod tests {
         let mut db_conn = control.db().lock().unwrap().connection();
         db_conn.new_unspent_coins(&[Coin {
             outpoint: dummy_op,
+            is_immature: false,
             block_info: None,
             amount: bitcoin::Amount::from_sat(100_000),
             derivation_index: bip32::ChildNumber::from(13),
@@ -1081,6 +1092,7 @@ mod tests {
         };
         db_conn.new_unspent_coins(&[Coin {
             outpoint: dummy_op_dup,
+            is_immature: false,
             block_info: None,
             amount: bitcoin::Amount::from_sat(400_000),
             derivation_index: bip32::ChildNumber::from(42),
@@ -1095,6 +1107,26 @@ mod tests {
             )))
         );
 
+        // Can't create a transaction that spends an immature coinbase deposit.
+        let imma_op = bitcoin::OutPoint::from_str(
+            "4753a1d74c0af8dd0a0f3b763c14faf3bd9ed03cbdf33337a074fb0e9f6c7810:0",
+        )
+        .unwrap();
+        db_conn.new_unspent_coins(&[Coin {
+            outpoint: imma_op,
+            is_immature: true,
+            block_info: None,
+            amount: bitcoin::Amount::from_sat(100_000),
+            derivation_index: bip32::ChildNumber::from(13),
+            is_change: false,
+            spend_txid: None,
+            spend_block: None,
+        }]);
+        assert_eq!(
+            control.create_spend(&destinations, &[imma_op], 1_001),
+            Err(CommandError::ImmatureCoinbase(imma_op))
+        );
+
         ms.shutdown();
     }
 
@@ -1127,6 +1159,7 @@ mod tests {
         db_conn.new_unspent_coins(&[
             Coin {
                 outpoint: dummy_op_a,
+                is_immature: false,
                 block_info: None,
                 amount: bitcoin::Amount::from_sat(100_000),
                 derivation_index: bip32::ChildNumber::from(13),
@@ -1136,6 +1169,7 @@ mod tests {
             },
             Coin {
                 outpoint: dummy_op_b,
+                is_immature: false,
                 block_info: None,
                 amount: bitcoin::Amount::from_sat(115_680),
                 derivation_index: bip32::ChildNumber::from(34),
@@ -1303,6 +1337,7 @@ mod tests {
             // Deposit 1
             Coin {
                 is_change: false,
+                is_immature: false,
                 outpoint: OutPoint {
                     txid: deposit1.txid(),
                     vout: 0,
@@ -1316,6 +1351,7 @@ mod tests {
             // Deposit 2
             Coin {
                 is_change: false,
+                is_immature: false,
                 outpoint: OutPoint {
                     txid: deposit2.txid(),
                     vout: 0,
@@ -1329,6 +1365,7 @@ mod tests {
             // This coin is a change output.
             Coin {
                 is_change: true,
+                is_immature: false,
                 outpoint: OutPoint::new(spend_tx.txid(), 1),
                 block_info: Some(BlockInfo { height: 3, time: 3 }),
                 spend_block: None,
@@ -1339,6 +1376,7 @@ mod tests {
             // Deposit 3
             Coin {
                 is_change: false,
+                is_immature: false,
                 outpoint: OutPoint {
                     txid: deposit3.txid(),
                     vout: 0,

src/database/mod.rs

@@ -91,6 +91,9 @@ pub trait DatabaseConnection {
     fn remove_coins(&mut self, coins: &[bitcoin::OutPoint]);
 
     /// Mark a set of coins as being confirmed at a specified height and block time.
+    /// NOTE: if the coin comes from an immature coinbase transaction, this will mark it as mature.
+    /// Immature coinbase deposits must not be confirmed before they are 100 blocks deep in the
+    /// chain.
     fn confirm_coins(&mut self, outpoints: &[(bitcoin::OutPoint, i32, u32)]);
 
     /// Mark a set of coins as being spent by a specified txid of a pending transaction.
@@ -281,6 +284,7 @@ impl From<DbBlockInfo> for BlockInfo {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct Coin {
     pub outpoint: bitcoin::OutPoint,
+    pub is_immature: bool,
     pub block_info: Option<BlockInfo>,
     pub amount: bitcoin::Amount,
     pub derivation_index: bip32::ChildNumber,
@@ -293,6 +297,7 @@ impl std::convert::From<DbCoin> for Coin {
     fn from(db_coin: DbCoin) -> Coin {
         let DbCoin {
             outpoint,
+            is_immature,
             block_info,
             amount,
             derivation_index,
@@ -303,6 +308,7 @@ impl std::convert::From<DbCoin> for Coin {
         } = db_coin;
         Coin {
             outpoint,
+            is_immature,
             block_info: block_info.map(BlockInfo::from),
             amount,
             derivation_index,