[STDCXX-1037] Bug in vector::swap() with unequal allocators

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 4.1.3, 4.1.4, 4.2.0, 4.2.1
• Fix Version/s: 4.2.2
• Component/s: 23. Containers

Environment

All

• Patch Info: Patch Available
• Severity: Incorrect Behavior
• Assignee: Farid Zaripov
• Reporter: Farid Zaripov
• Created: 04/Aug/09 13:53
• Updated: 14/Aug/09 16:45
• Resolved: 14/Aug/09 16:38

Description

The test below fails with assertion:

Assertion failed: 1 == v1.size() && 2 == v1.front(), file test.cpp, line 32

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

test.cpp

#include <cassert>
#include <memory>
#include <vector>

template <typename T>
class Alloc : public std::allocator<T>
{
public:
    Alloc(int i) : i_(i) { }

    int i_;
};

template <typename T>
bool operator==(const Alloc<T>& a1, const Alloc<T>& a2)
{
    return a1.i_ == a2.i_;
}

int main ()
{
    std::vector<int, Alloc<int> > v1(Alloc<int>(1));
    v1.push_back(1);
    assert(1 == v1.size() && 1 == v1.front());

    std::vector<int, Alloc<int> > v2(Alloc<int>(2));
    v2.push_back(2);
    assert(1 == v2.size() && 2 == v2.front());

    v1.swap(v2);

    assert(1 == v1.size() && 2 == v1.front());
    assert(1 == v2.size() && 1 == v2.front());

    return 0;
}

The bug was introduced in r355174

The proposed patch:

vector.cc.diff

Index: vector.cc
===================================================================
--- vector.cc	(revision 800774)
+++ vector.cc	(working copy)
@@ -133,6 +133,7 @@
     _RWSTD_ASSERT (__tmp.get_allocator () == __other.get_allocator ());
 
     __tmp.assign (begin (), end ());
+    assign (__other.begin (), __other.end ());
     __other.swap (__tmp);
 }