From e28655778b07fe5761adf9cea60a87e2e499c4fd Mon Sep 17 00:00:00 2001
From: Daniel Bate <djbate23@gmail.com>
Date: Fri, 30 Aug 2024 13:42:55 +0100
Subject: [PATCH] fix: `UtxoIdCoder` output index to be `u16` (#3064)
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* fix: utxo id output index to be u16

* chore: changeset

* chore: lint

---------

Co-authored-by: Sérgio Torres <30977845+Torres-ssf@users.noreply.github.com>
---
 .changeset/thin-shrimps-remain.md                |  5 +++++
 packages/transactions/src/coders/utxo-id.test.ts | 16 +++++++++++++++-
 packages/transactions/src/coders/utxo-id.ts      |  2 +-
 3 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/thin-shrimps-remain.md

diff --git a/.changeset/thin-shrimps-remain.md b/.changeset/thin-shrimps-remain.md
new file mode 100644
index 00000000000..a5cda006e36
--- /dev/null
+++ b/.changeset/thin-shrimps-remain.md
@@ -0,0 +1,5 @@
+---
+"@fuel-ts/transactions": patch
+---
+
+fix: `UtxoIdCoder` output index to be `u16`
diff --git a/packages/transactions/src/coders/utxo-id.test.ts b/packages/transactions/src/coders/utxo-id.test.ts
index 744ec43c692..a1e72ee6670 100644
--- a/packages/transactions/src/coders/utxo-id.test.ts
+++ b/packages/transactions/src/coders/utxo-id.test.ts
@@ -10,7 +10,7 @@ const B256 = '0xd5579c46dfcc7f18207013e65b44e4cb4e2c2298f4ac457ba8f82743f31e930b
  * @group browser
  */
 describe('UtxoIdCoder', () => {
-  it('can encode UtxoId', () => {
+  it('can encode UtxoId [u8 output]', () => {
     const utxoId: UtxoId = {
       transactionId: B256,
       outputIndex: 0,
@@ -27,6 +27,20 @@ describe('UtxoIdCoder', () => {
     expect(offset).toEqual(40);
     expect(decoded).toEqual(utxoId);
   });
+
+  it('can encode UtxoId [u16 output]', () => {
+    const utxoId: UtxoId = {
+      transactionId: B256,
+      outputIndex: 256,
+    };
+
+    const encoded = hexlify(new UtxoIdCoder().encode(utxoId));
+
+    expect(encoded).toEqual(
+      '0xd5579c46dfcc7f18207013e65b44e4cb4e2c2298f4ac457ba8f82743f31e930b0000000000000100'
+    );
+  });
+
   it('does not encode bad UtxoId', () => {
     const utxoId: UtxoId = {
       // @ts-expect-error: Values shouldn't be assignable
diff --git a/packages/transactions/src/coders/utxo-id.ts b/packages/transactions/src/coders/utxo-id.ts
index c6b0688e937..a967e626c7c 100644
--- a/packages/transactions/src/coders/utxo-id.ts
+++ b/packages/transactions/src/coders/utxo-id.ts
@@ -14,7 +14,7 @@ export class UtxoIdCoder extends StructCoder<{
   constructor() {
     super('UtxoId', {
       transactionId: new B256Coder(),
-      outputIndex: new NumberCoder('u8', { padToWordSize: true }),
+      outputIndex: new NumberCoder('u16', { padToWordSize: true }),
     });
   }
 }