flat_multimap leaks on insert(Iterator, Iterator)

[adam.m.baxter@…]

Reproducer:

#include <iostream> #include <boost/container/flat_map.hpp>

typedef boost::container::flat_multimap<int,int> IntMap;

class MapTest { public:

MapTest() {} MapTest(IntMap const &map) :

_map(map) { _map.insert(map.begin(), map.end());

} IntMap const& getMap() {return _map; }

private:

IntMap _map;

};

int main(int argc, char *argv[]) {

using std::cout; using std::endl;

IntMap iMap; for(int i = 0; i < 1000; i++) {

iMap.emplace(i, i);

}

MapTest map(iMap); for(auto const &kvPair : map.getMap()) {

cout << kvPair.first << " : " << kvPair.second << endl;

} return 0;

}

Valgrind Output:

==15820== ==15820== HEAP SUMMARY: ==15820== in use at exit: 8,000 bytes in 1 blocks ==15820== total heap usage: 20 allocs, 19 frees, 49,624 bytes allocated ==15820== ==15820== 8,000 bytes in 1 blocks are definitely lost in loss record 1 of 1 ==15820== at 0x4A068F3: operator new(unsigned long) (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) ==15820== by 0x4016EF: MapTest::MapTest(boost::container::flat_multimap<int, int, std::less<int>, std::allocator<std::pair<int, int> > > const&) (in /home/abaxter/Projects/Du/apollo-build/bin/sandbox) ==15820== by 0x4013B9: main (in /home/abaxter/Projects/Du/apollo-build/bin/sandbox) ==15820== ==15820== LEAK SUMMARY: ==15820== definitely lost: 8,000 bytes in 1 blocks ==15820== indirectly lost: 0 bytes in 0 blocks ==15820== possibly lost: 0 bytes in 0 blocks ==15820== still reachable: 0 bytes in 0 blocks ==15820== suppressed: 0 bytes in 0 blocks ==15820==

[adam.m.baxter@…]

Reproducer program

[Adam Baxter <adam.m.baxter@…>]

Valgrind error message

[Adam Baxter <adam.m.baxter@…>]

Apparently the copy got butchered as I forgot to do any formatting. I've attached the sandbox program and valgrind message to this ticket.

While the program does a nonsensical thing, it was the only way I could get the bug to reproduce in something so simple

[Adam Baxter <adam.m.baxter@…>]

I have proof that a similar thing happens with flat maps, but I'm unable to successfully create a reproducer at this point.

[Ion Gaztañaga]

I just noticed that this is not a flat_xxx problem but vector's problem. The reserve() function leaks memory.

[Ion Gaztañaga]

(In [85658]) Fixes #9108

[Adam Baxter <adam.m.baxter@…>]

Thanks!