From ebe3d2d59d34f8d3c4d04ed42b4e8f958b2a6829 Mon Sep 17 00:00:00 2001
From: Pierre <pierre.duval@gadz.org>
Date: Mon, 21 Feb 2022 17:20:11 +1100
Subject: [PATCH] fix: simulateTransaction accounts items can be null (#23229)

* fix: simulated accounts can be null

* Use Missing rather than token program id

Co-authored-by: Arrowana <8245419+Arrowana@users.noreply.github.com>
---
 web3.js/src/connection.ts       | 18 ++++++++++--------
 web3.js/test/connection.test.ts | 10 ++++++++--
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/web3.js/src/connection.ts b/web3.js/src/connection.ts
index e97db4a06e..056a60019f 100644
--- a/web3.js/src/connection.ts
+++ b/web3.js/src/connection.ts
@@ -469,7 +469,7 @@ export type SimulatedTransactionAccountInfo = {
 export type SimulatedTransactionResponse = {
   err: TransactionError | string | null;
   logs: Array<string> | null;
-  accounts?: SimulatedTransactionAccountInfo[] | null;
+  accounts?: (SimulatedTransactionAccountInfo | null)[] | null;
   unitsConsumed?: number;
 };
 
@@ -480,13 +480,15 @@ const SimulatedTransactionResponseStruct = jsonRpcResultAndContext(
     accounts: optional(
       nullable(
         array(
-          pick({
-            executable: boolean(),
-            owner: string(),
-            lamports: number(),
-            data: array(string()),
-            rentEpoch: optional(number()),
-          }),
+          nullable(
+            pick({
+              executable: boolean(),
+              owner: string(),
+              lamports: number(),
+              data: array(string()),
+              rentEpoch: optional(number()),
+            }),
+          ),
         ),
       ),
     ),
diff --git a/web3.js/test/connection.test.ts b/web3.js/test/connection.test.ts
index 6e37326878..aa2aba618b 100644
--- a/web3.js/test/connection.test.ts
+++ b/web3.js/test/connection.test.ts
@@ -3044,10 +3044,16 @@ describe('Connection', () => {
       const results2 = await connection.simulateTransaction(
         message,
         [account1],
-        [account1.publicKey],
+        [
+          account1.publicKey,
+          new PublicKey('Missing111111111111111111111111111111111111'),
+        ],
       );
 
-      expect(results2.value.accounts).lengthOf(1);
+      expect(results2.value.accounts).lengthOf(2);
+      if (results2.value.accounts) {
+        expect(results2.value.accounts[1]).to.be.null;
+      }
     }).timeout(10000);
 
     it('transaction', async () => {