From b8eff73829572403008bad14ff4be4d47835330b Mon Sep 17 00:00:00 2001
From: mao <118530756+maoxor@users.noreply.github.com>
Date: Thu, 29 Oct 2026 17:29:54 +0100
Subject: [PATCH] fix: keep single quotes around strings containing \u{

In a double-quoted string, PHP treats any `\u{` as the start of a code point escape and fails to parse the file when it is not a valid one, so `'\u{%04X}'` must not become `"\u{%04X}"`.
---
 src/util.mjs                                                | 3 ++-
 tests/string-double-quote/__snapshots__/jsfmt.spec.mjs.snap | 6 ++++++
 tests/string-double-quote/quoting.php                       | 3 +++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/util.mjs b/src/util.mjs
index 8a4aa944d..d97087240 100644
--- a/src/util.mjs
+++ b/src/util.mjs
@@ -538,8 +538,9 @@ function useDoubleQuote(node, options) {
   if (node.isDoubleQuote === options.singleQuote) {
     // We have a double quote and the user passed singleQuote:true, or the other way around.
     const rawValue = node.raw.slice(node.raw[0] === "b" ? 2 : 1, -1);
+    // In double quotes, PHP reads any `\u{` as a code point escape and rejects an invalid one.
     const isComplex = rawValue.match(
-      /\\([$nrtfve]|[xX][0-9a-fA-F]{1,2}|[0-7]{1,3}|u{([0-9a-fA-F]+)})|\r?\n|'|"|\$/
+      /\\([$nrtfve]|[xX][0-9a-fA-F]{1,2}|[0-7]{1,3}|u{)|\r?\n|'|"|\$/
     );
     return node.isDoubleQuote ? isComplex : !isComplex;
   }
diff --git a/tests/string-double-quote/__snapshots__/jsfmt.spec.mjs.snap b/tests/string-double-quote/__snapshots__/jsfmt.spec.mjs.snap
index 451d79ebd..848bcfbfa 100644
--- a/tests/string-double-quote/__snapshots__/jsfmt.spec.mjs.snap
+++ b/tests/string-double-quote/__snapshots__/jsfmt.spec.mjs.snap
@@ -34,6 +34,9 @@ singleQuote: false
 '\\u{aa}';
 '\\u{0000aa}';
 '\\u{9999}';
+'\\u{%04X}';
+'\\u{';
+'\\u{zz}';
 'multi
 line';
 '\\\\';
@@ -73,6 +76,9 @@ b'binary string\\n';
 '\\u{aa}';
 '\\u{0000aa}';
 '\\u{9999}';
+'\\u{%04X}';
+'\\u{';
+'\\u{zz}';
 'multi
 line';
 "\\\\";
diff --git a/tests/string-double-quote/quoting.php b/tests/string-double-quote/quoting.php
index eab1fee4b..38b4d41d1 100644
--- a/tests/string-double-quote/quoting.php
+++ b/tests/string-double-quote/quoting.php
@@ -25,6 +25,9 @@
 '\u{aa}';
 '\u{0000aa}';
 '\u{9999}';
+'\u{%04X}';
+'\u{';
+'\u{zz}';
 'multi
 line';
 '\\';