enforce coinbase maturity rule, skip shielded-only rule instead

zebra-chain/src/transaction.rs

@@ -310,7 +310,7 @@ impl Transaction {
             // because of other consensus rules
             OnlyShieldedOutputs { spend_height }
         } else {
-            SomeTransparentOutputs
+            SomeTransparentOutputs { spend_height }
         }
     }
 

zebra-chain/src/transparent/utxo.rs

@@ -126,7 +126,10 @@ impl OrderedUtxo {
 )]
 pub enum CoinbaseSpendRestriction {
     /// The UTXO is spent in a transaction with one or more transparent outputs
-    SomeTransparentOutputs,
+    SomeTransparentOutputs {
+        /// The height at which the UTXO is spent
+        spend_height: block::Height,
+    },
 
     /// The UTXO is spent in a transaction which only has shielded outputs
     OnlyShieldedOutputs {

zebra-state/src/service/check/tests/utxo.rs

@@ -83,7 +83,10 @@ fn reject_unshielded_coinbase_utxo_spend() {
     };
     let ordered_utxo = transparent::OrderedUtxo::new(output, created_height, 0);
 
-    let spend_restriction = transparent::CoinbaseSpendRestriction::SomeTransparentOutputs;
+    let spend_restriction = transparent::CoinbaseSpendRestriction::SomeTransparentOutputs {
+        // Use some fake height, this is only used on Regtest
+        spend_height: Height::MIN,
+    };
 
     let result = check::utxo::transparent_coinbase_spend(
         outpoint,

zebra-state/src/service/check/utxo.rs

@@ -204,23 +204,26 @@ pub fn transparent_coinbase_spend(
         return Ok(());
     }
 
-    match spend_restriction {
-        OnlyShieldedOutputs { spend_height } => {
-            let min_spend_height = utxo.height + MIN_TRANSPARENT_COINBASE_MATURITY.into();
-            let min_spend_height =
-                min_spend_height.expect("valid UTXOs have coinbase heights far below Height::MAX");
-            if spend_height >= min_spend_height || network.is_regtest() {
-                Ok(())
-            } else {
-                Err(ImmatureTransparentCoinbaseSpend {
-                    outpoint,
-                    spend_height,
-                    min_spend_height,
-                    created_height: utxo.height,
-                })
-            }
+    let spend_height = match spend_restriction {
+        OnlyShieldedOutputs { spend_height } => spend_height,
+        SomeTransparentOutputs { spend_height } if network.is_regtest() => spend_height,
+        SomeTransparentOutputs { .. } => {
+            return Err(UnshieldedTransparentCoinbaseSpend { outpoint })
         }
-        SomeTransparentOutputs => Err(UnshieldedTransparentCoinbaseSpend { outpoint }),
+    };
+
+    let min_spend_height = utxo.height + MIN_TRANSPARENT_COINBASE_MATURITY.into();
+    let min_spend_height =
+        min_spend_height.expect("valid UTXOs have coinbase heights far below Height::MAX");
+    if spend_height >= min_spend_height {
+        Ok(())
+    } else {
+        Err(ImmatureTransparentCoinbaseSpend {
+            outpoint,
+            spend_height,
+            min_spend_height,
+            created_height: utxo.height,
+        })
     }
 }