From ab8b14906242863326ef8bd0c085476200a7a3d8 Mon Sep 17 00:00:00 2001
From: Joe C <joecaulfield29@yahoo.com>
Date: Wed, 30 Aug 2023 01:25:30 -0600
Subject: [PATCH] refactor(experimental): add opaque type for serialized
 message (#1543)

---
 .../src/rpc-methods/__tests__/get-fee-for-message-test.ts | 8 ++++----
 packages/rpc-core/src/rpc-methods/getFeeForMessage.ts     | 7 ++++---
 packages/transactions/src/serializers/message.ts          | 7 ++++---
 packages/transactions/src/types.ts                        | 4 ++++
 4 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/packages/rpc-core/src/rpc-methods/__tests__/get-fee-for-message-test.ts b/packages/rpc-core/src/rpc-methods/__tests__/get-fee-for-message-test.ts
index f3b2a5aaa9f2..0eb8267c08a6 100644
--- a/packages/rpc-core/src/rpc-methods/__tests__/get-fee-for-message-test.ts
+++ b/packages/rpc-core/src/rpc-methods/__tests__/get-fee-for-message-test.ts
@@ -2,10 +2,10 @@ import { base58, base64, fixSerializer } from '@metaplex-foundation/umi-serializ
 import { createHttpTransport, createJsonRpc } from '@solana/rpc-transport';
 import type { SolanaJsonRpcErrorCode } from '@solana/rpc-transport/dist/types/json-rpc-errors';
 import type { Rpc } from '@solana/rpc-transport/dist/types/json-rpc-types';
-import { Blockhash } from '@solana/transactions';
+import { Blockhash, SerializedMessageBytesBase64 } from '@solana/transactions';
 import fetchMock from 'jest-fetch-mock-fork';
 
-import { Base64EncodedBytes, Commitment } from '../common';
+import { Commitment } from '../common';
 import { createSolanaRpcApi, SolanaRpcMethods } from '../index';
 
 // See scripts/fixtures/send-transaction-fee-payer.json
@@ -50,7 +50,7 @@ function getMockTransactionMessage(blockhash: Blockhash) {
         0x00, // Number of address table lookups
     ]);
     const messageBase64 = base64.deserialize(message)[0];
-    return messageBase64 as Base64EncodedBytes;
+    return messageBase64 as SerializedMessageBytesBase64;
 }
 
 describe('getFeeForMessage', () => {
@@ -114,7 +114,7 @@ describe('getFeeForMessage', () => {
     describe('when called with an invalid message', () => {
         it('throws an error', async () => {
             expect.assertions(1);
-            const sendPromise = rpc.getFeeForMessage('someInvalidMessage' as Base64EncodedBytes).send();
+            const sendPromise = rpc.getFeeForMessage('someInvalidMessage' as SerializedMessageBytesBase64).send();
             await expect(sendPromise).rejects.toMatchObject({
                 code: -32602 satisfies (typeof SolanaJsonRpcErrorCode)['JSON_RPC_INVALID_PARAMS'],
                 message: expect.any(String),
diff --git a/packages/rpc-core/src/rpc-methods/getFeeForMessage.ts b/packages/rpc-core/src/rpc-methods/getFeeForMessage.ts
index 1928826d91b6..82dc6410dbe8 100644
--- a/packages/rpc-core/src/rpc-methods/getFeeForMessage.ts
+++ b/packages/rpc-core/src/rpc-methods/getFeeForMessage.ts
@@ -1,4 +1,6 @@
-import { Base64EncodedBytes, Commitment, RpcResponse, Slot, U64UnsafeBeyond2Pow53Minus1 } from './common';
+import { SerializedMessageBytesBase64 } from '@solana/transactions';
+
+import { Commitment, RpcResponse, Slot, U64UnsafeBeyond2Pow53Minus1 } from './common';
 
 /** Fee corresponding to the message at the specified blockhash */
 type GetFeeForMessageApiResponse = RpcResponse<U64UnsafeBeyond2Pow53Minus1 | null>;
@@ -8,8 +10,7 @@ export interface GetFeeForMessageApi {
      * Returns the fee the network will charge for a particular Message
      */
     getFeeForMessage(
-        /** Base-64 encoded message */
-        message: Base64EncodedBytes,
+        message: SerializedMessageBytesBase64,
         config?: Readonly<{
             commitment?: Commitment;
             minContextSlot?: Slot;
diff --git a/packages/transactions/src/serializers/message.ts b/packages/transactions/src/serializers/message.ts
index c8f12f24f689..fe3965eaea17 100644
--- a/packages/transactions/src/serializers/message.ts
+++ b/packages/transactions/src/serializers/message.ts
@@ -11,6 +11,7 @@ import {
 import { getBase58EncodedAddressCodec } from '@solana/addresses';
 
 import { CompiledMessage } from '../message';
+import { SerializedMessageBytes } from '../types';
 import { getAddressTableLookupCodec } from './address-table-lookup';
 import { getMessageHeaderCodec } from './header';
 import { getInstructionCodec } from './instruction';
@@ -42,9 +43,9 @@ function deserialize(bytes: Uint8Array, offset = 0): [CompiledMessage, number] {
     ];
 }
 
-function serialize(compiledMessage: CompiledMessage) {
+function serialize(compiledMessage: CompiledMessage): SerializedMessageBytes {
     if (compiledMessage.version === 'legacy') {
-        return struct(getPreludeStructSerializerTuple()).serialize(compiledMessage);
+        return struct(getPreludeStructSerializerTuple()).serialize(compiledMessage) as SerializedMessageBytes;
     } else {
         return mapSerializer(
             struct([
@@ -60,7 +61,7 @@ function serialize(compiledMessage: CompiledMessage) {
                     addressTableLookups: value.addressTableLookups ?? [],
                 } as Exclude<CompiledMessage, { readonly version: 'legacy' }>;
             }
-        ).serialize(compiledMessage);
+        ).serialize(compiledMessage) as SerializedMessageBytes;
     }
 }
 
diff --git a/packages/transactions/src/types.ts b/packages/transactions/src/types.ts
index 3a6220459d1a..ecb4ae07ca9f 100644
--- a/packages/transactions/src/types.ts
+++ b/packages/transactions/src/types.ts
@@ -1,5 +1,9 @@
 import { IAccountMeta, IInstruction } from '@solana/instructions';
 
+/** A string of bytes that are definitely a serialized message */
+export type SerializedMessageBytes = Uint8Array & { readonly __serializedMessageBytes: unique symbol };
+export type SerializedMessageBytesBase64 = string & { readonly __serializedMessageBytesBase64: unique symbol };
+
 export type BaseTransaction = Readonly<{
     instructions: readonly IInstruction[];
     version: TransactionVersion;