[Boost-bugs] [Boost C++ Libraries] #2532: ptr_set<T>::erase(const T&) does not update the tree

Subject: [Boost-bugs] [Boost C++ Libraries] #2532: ptr_set<T>::erase(const T&) does not update the tree
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2008-11-24 23:58:25

#2532: ptr_set<T>::erase(const T&) does not update the tree
-------------------------------------+--------------------------------------
 Reporter:  ayba_at_[hidden]             |       Owner:  nesotto      
     Type:  Bugs                     |      Status:  new          
Milestone:  Boost 1.38.0             |   Component:  ptr_container
  Version:  Boost Development Trunk  |    Severity:  Problem      
 Keywords:  ptr_set erase            |  
-------------------------------------+--------------------------------------
 Hi

 In some cases ptr_set<T>::erase(const T&) deletes the object as expected
 but does not remove the node in the tree.

 => the tree is left with a dangling pointer


 Consider the following example:

 {{{
 #include <boost/ptr_container/ptr_set.hpp>
 #include <boost/foreach.hpp>
 #include <iostream>

 using namespace std;

 class Int
 {
 public:
         Int (int v) : val (v) {
                 cout << "\t\tnew:    " << this << " -> " << val << endl;
         }
         ~Int () {
                 cout << "\t\tdelete: " << this << " -> " << val << endl;
         }

         bool operator< (const Int& b) const { return val < b.val; }

         int val;
 };

 int main()
 {
         boost::ptr_set<Int> s;

         s.insert (new Int (3));
         s.insert (new Int (1));
         s.insert (new Int (2));

         BOOST_FOREACH (Int& i, s) {
                 cout << &i << " -> " << i.val << endl;
         }
         cout << endl;

         s.erase (Int(2));

         BOOST_FOREACH (Int& i, s) {
                 cout << &i << " -> " << i.val << endl;
         }

         return 0;
 }
 }}}

 --> output
 {{{
                 new:    0x9759008 -> 3
                 new:    0x9759030 -> 1
                 new:    0x9759058 -> 2
 0x9759030 -> 1
 0x9759058 -> 2
 0x9759008 -> 3

                 new:    0xbfe387ac -> 2
                 delete: 0x9759058 -> 2      <---- object deleted
                 delete: 0xbfe387ac -> 2
 0x9759030 -> 1
 0x9759058 -> 0                              <---- dangling node/pointer
 !!!
 0x9759008 -> 3
                 delete: 0x9759030 -> 1
                 delete: 0x9759058 -> 0      <---- object deleted again !!!
                 delete: 0x9759008 -> 3
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/2532>
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