From d56586eec66b00376b60a44265aa179e48d0de69 Mon Sep 17 00:00:00 2001
From: Meghan Denny <meghan@bun.sh>
Date: Wed, 11 Dec 2024 23:47:53 -0800
Subject: [PATCH] fix test-buffer-badhex.js

---
 src/bun.js/webcore/encoding.zig               |  4 +-
 .../node/test/parallel/test-buffer-badhex.js  | 48 +++++++++++++++++++
 2 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 test/js/node/test/parallel/test-buffer-badhex.js

diff --git a/src/bun.js/webcore/encoding.zig b/src/bun.js/webcore/encoding.zig
index f50424ea35..57aa62e122 100644
--- a/src/bun.js/webcore/encoding.zig
+++ b/src/bun.js/webcore/encoding.zig
@@ -1335,7 +1335,7 @@ pub const Encoder = struct {
             },
 
             .hex => {
-                return strings.decodeHexToBytes(to_ptr[0..to_len], u8, input[0..len]);
+                return strings.decodeHexToBytesTruncate(to_ptr[0..to_len], u8, input[0..len]);
             },
 
             .base64, .base64url => {
@@ -1414,7 +1414,7 @@ pub const Encoder = struct {
             },
 
             .hex => {
-                return strings.decodeHexToBytes(to[0..to_len], u16, input[0..len]);
+                return strings.decodeHexToBytesTruncate(to[0..to_len], u16, input[0..len]);
             },
 
             .base64, .base64url => {
diff --git a/test/js/node/test/parallel/test-buffer-badhex.js b/test/js/node/test/parallel/test-buffer-badhex.js
new file mode 100644
index 0000000000..61086659fa
--- /dev/null
+++ b/test/js/node/test/parallel/test-buffer-badhex.js
@@ -0,0 +1,48 @@
+'use strict';
+require('../common');
+const assert = require('assert');
+
+// Test hex strings and bad hex strings
+{
+  const buf = Buffer.alloc(4);
+  assert.strictEqual(buf.length, 4);
+  assert.deepStrictEqual(buf, Buffer.from([0, 0, 0, 0]));
+  assert.strictEqual(buf.write('abcdxx', 0, 'hex'), 2);
+  assert.deepStrictEqual(buf, Buffer.from([0xab, 0xcd, 0x00, 0x00]));
+  assert.strictEqual(buf.toString('hex'), 'abcd0000');
+  assert.strictEqual(buf.write('abcdef01', 0, 'hex'), 4);
+  assert.deepStrictEqual(buf, Buffer.from([0xab, 0xcd, 0xef, 0x01]));
+  assert.strictEqual(buf.toString('hex'), 'abcdef01');
+
+  const copy = Buffer.from(buf.toString('hex'), 'hex');
+  assert.strictEqual(buf.toString('hex'), copy.toString('hex'));
+}
+
+{
+  const buf = Buffer.alloc(5);
+  assert.strictEqual(buf.write('abcdxx', 1, 'hex'), 2);
+  assert.strictEqual(buf.toString('hex'), '00abcd0000');
+}
+
+{
+  const buf = Buffer.alloc(4);
+  assert.deepStrictEqual(buf, Buffer.from([0, 0, 0, 0]));
+  assert.strictEqual(buf.write('xxabcd', 0, 'hex'), 0);
+  assert.deepStrictEqual(buf, Buffer.from([0, 0, 0, 0]));
+  assert.strictEqual(buf.write('xxab', 1, 'hex'), 0);
+  assert.deepStrictEqual(buf, Buffer.from([0, 0, 0, 0]));
+  assert.strictEqual(buf.write('cdxxab', 0, 'hex'), 1);
+  assert.deepStrictEqual(buf, Buffer.from([0xcd, 0, 0, 0]));
+}
+
+{
+  const buf = Buffer.alloc(256);
+  for (let i = 0; i < 256; i++)
+    buf[i] = i;
+
+  const hex = buf.toString('hex');
+  assert.deepStrictEqual(Buffer.from(hex, 'hex'), buf);
+
+  const badHex = `${hex.slice(0, 256)}xx${hex.slice(256, 510)}`;
+  assert.deepStrictEqual(Buffer.from(badHex, 'hex'), buf.slice(0, 128));
+}