Renames CoinbaseSpendRestriction variants and updates their documenta…

…tion.

Updates a comment.

zebra-chain/src/block/arbitrary.rs

@@ -650,7 +650,8 @@ where
         + 'static,
 {
     let has_shielded_outputs = transaction.has_shielded_outputs();
-    let delete_transparent_outputs = CoinbaseSpendRestriction::OnlyShieldedOutputs { spend_height };
+    let delete_transparent_outputs =
+        CoinbaseSpendRestriction::CheckCoinbaseMaturity { spend_height };
     let mut attempts: usize = 0;
 
     // choose an arbitrary spendable UTXO, in hash set order

zebra-chain/src/transaction.rs

@@ -307,11 +307,11 @@ impl Transaction {
         spend_height: block::Height,
     ) -> CoinbaseSpendRestriction {
         if self.outputs().is_empty() || network.should_allow_unshielded_coinbase_spends() {
-            // we know this transaction must have shielded outputs,
-            // because of other consensus rules
-            OnlyShieldedOutputs { spend_height }
+            // we know this transaction must have shielded outputs if it has no
+            // transparent outputs, because of other consensus rules.
+            CheckCoinbaseMaturity { spend_height }
         } else {
-            SomeTransparentOutputs
+            DisallowCoinbaseSpend
         }
     }
 

zebra-chain/src/transparent/utxo.rs

@@ -126,10 +126,14 @@ impl OrderedUtxo {
 )]
 pub enum CoinbaseSpendRestriction {
     /// The UTXO is spent in a transaction with one or more transparent outputs
-    SomeTransparentOutputs,
+    /// on a network where coinbase outputs must not be spent by transactions
+    /// with transparent outputs.
+    DisallowCoinbaseSpend,
 
-    /// The UTXO is spent in a transaction which only has shielded outputs
-    OnlyShieldedOutputs {
+    /// The UTXO is spent in a transaction which only has shielded outputs, or
+    /// transactions spending coinbase outputs may have transparent outputs on
+    /// this network.
+    CheckCoinbaseMaturity {
         /// The height at which the UTXO is spent
         spend_height: block::Height,
     },

zebra-consensus/src/transaction/tests.rs

@@ -848,7 +848,7 @@ async fn mempool_request_with_transparent_coinbase_spend_is_accepted_on_regtest(
 
     assert_eq!(
         spend_restriction,
-        CoinbaseSpendRestriction::OnlyShieldedOutputs {
+        CoinbaseSpendRestriction::CheckCoinbaseMaturity {
             spend_height: height
         }
     );

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

@@ -48,7 +48,7 @@ fn accept_shielded_mature_coinbase_utxo_spend() {
     let ordered_utxo = transparent::OrderedUtxo::new(output, created_height, 0);
 
     let min_spend_height = Height(created_height.0 + MIN_TRANSPARENT_COINBASE_MATURITY);
-    let spend_restriction = transparent::CoinbaseSpendRestriction::OnlyShieldedOutputs {
+    let spend_restriction = transparent::CoinbaseSpendRestriction::CheckCoinbaseMaturity {
         spend_height: min_spend_height,
     };
 
@@ -78,7 +78,7 @@ 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::DisallowCoinbaseSpend;
 
     let result =
         check::utxo::transparent_coinbase_spend(outpoint, spend_restriction, ordered_utxo.as_ref());
@@ -104,7 +104,7 @@ fn reject_immature_coinbase_utxo_spend() {
     let min_spend_height = Height(created_height.0 + MIN_TRANSPARENT_COINBASE_MATURITY);
     let spend_height = Height(min_spend_height.0 - 1);
     let spend_restriction =
-        transparent::CoinbaseSpendRestriction::OnlyShieldedOutputs { spend_height };
+        transparent::CoinbaseSpendRestriction::CheckCoinbaseMaturity { spend_height };
 
     let result =
         check::utxo::transparent_coinbase_spend(outpoint, spend_restriction, ordered_utxo.as_ref());

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

@@ -197,7 +197,7 @@ pub fn transparent_coinbase_spend(
     }
 
     match spend_restriction {
-        OnlyShieldedOutputs { spend_height } => {
+        CheckCoinbaseMaturity { 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");
@@ -212,7 +212,7 @@ pub fn transparent_coinbase_spend(
                 })
             }
         }
-        SomeTransparentOutputs => Err(UnshieldedTransparentCoinbaseSpend { outpoint }),
+        DisallowCoinbaseSpend => Err(UnshieldedTransparentCoinbaseSpend { outpoint }),
     }
 }