Add exception guard for vector(n, x, a) constructor

[winner245]

Overview of Changes

Added exception guard to the vector(n, x, a) constructor to enhance exception safety.

Details

This change ensures that the vector(n, x, a) constructor is consistent with other constructors, such as vector(n, x) and vector(n, a), in terms of exception safety.

Impact

Improves robustness and resource management during exceptions.

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[llvmbot]

@llvm/pr-subscribers-libcxx

Author: None (winner245)

Changes

Overview of Changes

Added exception guard to the vector(n, x, a) constructor to enhance exception safety.

Details

This change ensures that the vector(n, x, a) constructor is consistent with other constructors, such as vector(n, x) and vector(n, a), in terms of exception safety.

Impact

Improves robustness and resource management during exceptions.

---

Full diff: https://github.com/llvm/llvm-project/pull/113070.diff

1 Files Affected:

• (modified) libcxx/include/vector (+2)

diff --git a/libcxx/include/vector b/libcxx/include/vector
index dc31f31838264c..700cb51f41eeb2 100644
--- a/libcxx/include/vector
+++ b/libcxx/include/vector
@@ -487,10 +487,12 @@ public:
   _LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI
   vector(size_type __n, const value_type& __x, const allocator_type& __a)
       : __alloc_(__a) {
+    auto __guard = std::__make_exception_guard(__destroy_vector(*this));
     if (__n > 0) {
       __vallocate(__n);
       __construct_at_end(__n, __x);
     }
+    __guard.__complete();
   }
 
   template <class _InputIterator,