From bd9fbc0cd30e8a70bb64a9ca212d2c38e6486a5b Mon Sep 17 00:00:00 2001
From: Claude Bot <claude-bot@bun.sh>
Date: Fri, 31 Oct 2025 02:15:35 +0000
Subject: [PATCH] Remove dead ucs2 case labels after normalization
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Since ucs2 is normalized to utf16le at the start of jsBufferFunction_transcode,
all `case BufferEncodingType::ucs2:` labels in the switch statements are
unreachable dead code. Removed them and added clarifying comments.

No functional changes - all tests still pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
---
 src/bun.js/bindings/JSBuffer.cpp | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/bun.js/bindings/JSBuffer.cpp b/src/bun.js/bindings/JSBuffer.cpp
index e59269c3a8..8795c2cdd2 100644
--- a/src/bun.js/bindings/JSBuffer.cpp
+++ b/src/bun.js/bindings/JSBuffer.cpp
@@ -2145,9 +2145,8 @@ static JSC::JSUint8Array* transcodeBuffer(
     switch (fromEncoding) {
     case BufferEncodingType::utf8: {
         switch (toEncoding) {
-        case BufferEncodingType::utf16le:
-        case BufferEncodingType::ucs2: {
-            // UTF-8 to UTF-16LE
+        case BufferEncodingType::utf16le: {
+            // UTF-8 to UTF-16LE (ucs2 normalized to utf16le earlier)
             size_t expectedLength = simdutf::utf16_length_from_utf8(reinterpret_cast<const char*>(source), sourceLength);
             result = createUninitializedBuffer(lexicalGlobalObject, expectedLength * 2);
             RETURN_IF_EXCEPTION(scope, nullptr);
@@ -2198,9 +2197,8 @@ static JSC::JSUint8Array* transcodeBuffer(
         }
         break;
     }
-    case BufferEncodingType::utf16le:
-    case BufferEncodingType::ucs2: {
-        // Source is UTF-16LE
+    case BufferEncodingType::utf16le: {
+        // Source is UTF-16LE (ucs2 normalized to utf16le earlier)
         size_t utf16Length = sourceLength / 2;
         const char16_t* utf16Source = reinterpret_cast<const char16_t*>(source);
 
@@ -2280,9 +2278,8 @@ static JSC::JSUint8Array* transcodeBuffer(
 
             return result;
         }
-        case BufferEncodingType::utf16le:
-        case BufferEncodingType::ucs2: {
-            // Latin1 to UTF-16LE
+        case BufferEncodingType::utf16le: {
+            // Latin1 to UTF-16LE (ucs2 normalized to utf16le earlier)
             result = createUninitializedBuffer(lexicalGlobalObject, sourceLength * 2);
             RETURN_IF_EXCEPTION(scope, nullptr);