From 8e1eae7dae43fa83d043a907f9e52815917be210 Mon Sep 17 00:00:00 2001
From: Ai Hoshino <ambiguous404@gmail.com>
Date: Mon, 23 Oct 2023 04:42:05 +0800
Subject: [PATCH] fix(node:buffer): fix Buffer.write stuck (#6651)

---
 src/string_immutable.zig    | 14 +++++++++-----
 test/js/node/buffer.test.js | 28 +++++++++++++++++++++++-----
 2 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/src/string_immutable.zig b/src/string_immutable.zig
index 00ee8d8355..8e6dc0ab2a 100644
--- a/src/string_immutable.zig
+++ b/src/string_immutable.zig
@@ -2079,12 +2079,16 @@ pub fn copyLatin1IntoUTF8StopOnNonASCII(buf_: []u8, comptime Type: type, latin1_
             }
         }
 
-        if (latin1.len > 0 and buf.len >= 2) {
-            if (comptime stop) return .{ .written = std.math.maxInt(u32), .read = std.math.maxInt(u32) };
+        if (latin1.len > 0) {
+            if (buf.len >= 2) {
+                if (comptime stop) return .{ .written = std.math.maxInt(u32), .read = std.math.maxInt(u32) };
 
-            buf[0..2].* = latin1ToCodepointBytesAssumeNotASCII(latin1[0]);
-            latin1 = latin1[1..];
-            buf = buf[2..];
+                buf[0..2].* = latin1ToCodepointBytesAssumeNotASCII(latin1[0]);
+                latin1 = latin1[1..];
+                buf = buf[2..];
+            } else {
+                break;
+            }
         }
     }
 
diff --git a/test/js/node/buffer.test.js b/test/js/node/buffer.test.js
index 450129b0ec..e178a65095 100644
--- a/test/js/node/buffer.test.js
+++ b/test/js/node/buffer.test.js
@@ -211,11 +211,29 @@ it("only top level parent propagates from a non-pooled instance", () => {
 });
 
 it("UTF-8 write() & slice()", () => {
-  const testValue = "\u00F6\u65E5\u672C\u8A9E"; // ö日本語
-  const buffer = Buffer.allocUnsafe(32);
-  const size = buffer.write(testValue, 0, "utf8");
-  const slice = buffer.toString("utf8", 0, size);
-  expect(slice).toBe(testValue);
+  {
+    const testValue = "\u00F6\u65E5\u672C\u8A9E"; // ö日本語
+    const buffer = Buffer.allocUnsafe(32);
+    const size = buffer.write(testValue, 0, "utf8");
+    const slice = buffer.toString("utf8", 0, size);
+    expect(slice).toBe(testValue);
+  }
+  {
+    const buffer = Buffer.allocUnsafe(1);
+    buffer.write("\x61");
+    buffer.write("\xFF");
+    expect(buffer).toStrictEqual(Buffer.from([0x61]));
+  }
+  {
+    const buffer = Buffer.alloc(5);
+    buffer.write("\x61\xFF\x62\xFF\x63", "utf8");
+    expect(buffer).toStrictEqual(Buffer.from([0x61, 0xc3, 0xbf, 0x62, 0x00]));
+  }
+  {
+    const buffer = Buffer.alloc(5);
+    buffer.write("\xFF\x61\xFF\x62\xFF", "utf8");
+    expect(buffer).toStrictEqual(Buffer.from([0xc3, 0xbf, 0x61, 0xc3, 0xbf]));
+  }
 });
 
 it("triple slice", () => {