disallow non-transferable and confidential transfer to be initialized without confidential mint burn

Author: samkim-crypto

clients/rust-legacy/tests/confidential_transfer.rs

@@ -3367,6 +3367,37 @@ async fn confidential_transfer_apply_pending_balance_frozen_account() {
     );
 }
 
+#[tokio::test]
+async fn fail_initialize_non_transferable_confidential_mint_without_mint_burn() {
+    let authority = Keypair::new();
+    let auto_approve_new_accounts = true;
+    let auditor_elgamal_keypair = ElGamalKeypair::new_rand();
+    let auditor_elgamal_pubkey = (*auditor_elgamal_keypair.pubkey()).into();
+
+    let mut context = TestContext::new().await;
+    let err = context
+        .init_token_with_mint(vec![
+            ExtensionInitializationParams::NonTransferable,
+            ExtensionInitializationParams::ConfidentialTransferMint {
+                authority: Some(authority.pubkey()),
+                auto_approve_new_accounts,
+                auditor_elgamal_pubkey: Some(auditor_elgamal_pubkey),
+            },
+        ])
+        .await
+        .unwrap_err();
+
+    assert_eq!(
+        err,
+        TokenClientError::Client(Box::new(TransportError::TransactionError(
+            TransactionError::InstructionError(
+                3,
+                InstructionError::Custom(TokenError::InvalidExtensionCombination as u32)
+            )
+        )))
+    );
+}
+
 #[cfg(test)]
 mod unit_tests {
 

interface/src/extension/mod.rs

@@ -1328,6 +1328,7 @@ impl ExtensionType {
         let mut confidential_mint_burn = false;
         let mut interest_bearing = false;
         let mut scaled_ui_amount = false;
+        let mut non_transferable = false;
 
         for extension_type in mint_extension_types {
             match extension_type {
@@ -1339,6 +1340,7 @@ impl ExtensionType {
                 ExtensionType::ConfidentialMintBurn => confidential_mint_burn = true,
                 ExtensionType::InterestBearingConfig => interest_bearing = true,
                 ExtensionType::ScaledUiAmount => scaled_ui_amount = true,
+                ExtensionType::NonTransferable => non_transferable = true,
                 _ => (),
             }
         }
@@ -1360,6 +1362,10 @@ impl ExtensionType {
             return Err(TokenError::InvalidExtensionCombination);
         }
 
+        if non_transferable && confidential_transfer_mint && !confidential_mint_burn {
+            return Err(TokenError::InvalidExtensionCombination);
+        }
+
         Ok(())
     }
 }