[libcxx-commits] [libcxx] [libc++][regex] Fix #51028 throw exception in the case of wrong range (PR #148231)

[Lazarev Alexei via libcxx-commits]

https://github.com/insanustu updated https://github.com/llvm/llvm-project/pull/148231

>From 988130cce90ab3343862fbec1b68a73cfc64dd3c Mon Sep 17 00:00:00 2001
From: "alexey.lazarev" <alexey.lazarev at tasking.com>
Date: Fri, 11 Jul 2025 13:16:14 +0200
Subject: [PATCH] [libc++][regex] Fix #51028 throw exception in the case of
 wrong range

---
 libcxx/include/__cxx03/regex                                   | 2 +-
 libcxx/include/regex                                           | 2 +-
 .../test/std/re/re.regex/re.regex.construct/bad_range.pass.cpp | 3 ++-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/libcxx/include/__cxx03/regex b/libcxx/include/__cxx03/regex
index b96d59d3a252a..fcf44f49b60da 100644
--- a/libcxx/include/__cxx03/regex
+++ b/libcxx/include/__cxx03/regex
@@ -2100,7 +2100,7 @@ public:
       __ranges_.push_back(
           std::make_pair(__traits_.transform(__b.begin(), __b.end()), __traits_.transform(__e.begin(), __e.end())));
     } else {
-      if (__b.size() != 1 || __e.size() != 1)
+      if (__b.size() != 1 || __e.size() != 1 || __b[0] > __e[0])
         __throw_regex_error<regex_constants::error_range>();
       if (__icase_) {
         __b[0] = __traits_.translate_nocase(__b[0]);
diff --git a/libcxx/include/regex b/libcxx/include/regex
index bbc21e244dd17..958168a88535d 100644
--- a/libcxx/include/regex
+++ b/libcxx/include/regex
@@ -2120,7 +2120,7 @@ public:
       __ranges_.push_back(
           std::make_pair(__traits_.transform(__b.begin(), __b.end()), __traits_.transform(__e.begin(), __e.end())));
     } else {
-      if (__b.size() != 1 || __e.size() != 1)
+      if (__b.size() != 1 || __e.size() != 1 || __b[0] > __e[0])
         std::__throw_regex_error<regex_constants::error_range>();
       if (__icase_) {
         __b[0] = __traits_.translate_nocase(__b[0]);
diff --git a/libcxx/test/std/re/re.regex/re.regex.construct/bad_range.pass.cpp b/libcxx/test/std/re/re.regex/re.regex.construct/bad_range.pass.cpp
index 023bc0ee79f44..cabd9ebec520e 100644
--- a/libcxx/test/std/re/re.regex/re.regex.construct/bad_range.pass.cpp
+++ b/libcxx/test/std/re/re.regex/re.regex.construct/bad_range.pass.cpp
@@ -33,6 +33,7 @@ int main(int, char**)
 {
     assert(error_range_thrown("([\\w-a])"));
     assert(error_range_thrown("([a-\\w])"));
+    assert(error_range_thrown("([w-a])"));
 
-  return 0;
+    return 0;
 }