fix: skip compressing program addresses during transaction message compression (anza-xyz#951)

* fix: skip compressing program addresses during transaction message compression

* refactor: Combined programAddress with other skip conditions in a single `if` block

* refactor(transaction-messages): filter out program addresses when building eligible lookup addresses

* test(transaction-messages): add case to ensure program addresses are not compressed when reused as accounts

* Create two-items-decide.md

---------

Co-authored-by: Steven Luscher <steveluscher@users.noreply.github.com>

Author: tanmay5114

.changeset/two-items-decide.md

@@ -0,0 +1,5 @@
+---
+"@solana/transaction-messages": patch
+---
+
+`compressTransactionMessageUsingAddressLookupTables()` will no longer convert an account to a lookup table account, if the address of that account is used as a program address anywhere in the transaction.

packages/transaction-messages/src/__tests__/compress-transaction-message-test.ts

@@ -578,4 +578,43 @@ describe('compressTransactionMessageUsingAddressLookupTables', () => {
 
         expect(result.instructions[0].accounts![0]).toBeFrozenObject();
     });
+
+    it('should not replace a program address that appears as an account in another instruction', () => {
+        const programAddressA = 'programA' as Address;
+        const programAddressB = 'programB' as Address;
+        const lookupTableAddress = 'lookupTableAddress' as Address;
+
+        // Create a transaction and append two instructions sequentially
+        const transactionMessage = appendTransactionMessageInstructions(
+            [
+                {
+                    accounts: [] as AccountMeta[],
+                    programAddress: programAddressA,
+                },
+                {
+                    accounts: [
+                        {
+                            address: programAddressA,
+                            role: AccountRole.READONLY,
+                        },
+                    ] as AccountMeta[],
+                    programAddress: programAddressB,
+                },
+            ],
+            createTransactionMessage({ version: 0 }),
+        );
+
+        const lookupTables: AddressesByLookupTableAddress = {
+            [lookupTableAddress]: [programAddressA],
+        };
+
+        const result = compressTransactionMessageUsingAddressLookupTables(transactionMessage, lookupTables);
+
+        // The first instruction’s programAddressA should be excluded from compression,
+        // even though it exists in the lookup table.
+        expect(result.instructions[1].accounts![0]).toStrictEqual({
+            address: programAddressA,
+            role: AccountRole.READONLY,
+        });
+    });
 });

packages/transaction-messages/src/compress-transaction-message.ts

@@ -93,8 +93,12 @@ export function compressTransactionMessageUsingAddressLookupTables<
     transactionMessage: TTransactionMessage,
     addressesByLookupTableAddress: AddressesByLookupTableAddress,
 ): TTransactionMessage | WidenTransactionMessageInstructions<TTransactionMessage> {
-    const lookupTableAddresses = new Set(Object.values(addressesByLookupTableAddress).flatMap(a => a));
-
+    const programAddresses = new Set(transactionMessage.instructions.map(ix => ix.programAddress));
+    const eligibleLookupAddresses = new Set(
+        Object.values(addressesByLookupTableAddress)
+            .flatMap(a => a)
+            .filter(address => !programAddresses.has(address)),
+    );
     const newInstructions: Instruction[] = [];
     let updatedAnyInstructions = false;
     for (const instruction of transactionMessage.instructions) {
@@ -109,7 +113,7 @@ export function compressTransactionMessageUsingAddressLookupTables<
             // If the address is already a lookup, is not in any lookup tables, or is a signer role, return as-is
             if (
                 'lookupTableAddress' in account ||
-                !lookupTableAddresses.has(account.address) ||
+                !eligibleLookupAddresses.has(account.address) ||
                 isSignerRole(account.role)
             ) {
                 newAccounts.push(account);