RVec's swap is broken when RVec is adopting memory #10297
Description
std::swap seems to be working fine, but the custom swap implementation is broken. Self-contained reproducer by @ikabadzhov :
#include <ROOT/RVec.hxx>
#include <iostream>
#include <vector>
int main() {
std::vector<int> v = {1};
ROOT::RVecI rvec1(v.data(), v.size());
ROOT::RVecI rvec2 = {2};
swap(rvec1, rvec2);
v[0] = 3;
std::cout << rvec1 << '\n' << rvec2 << '\n';
}This should print 2 and 3 but instead it prints 3 and 1.
Critically, this might be problematic for non-trivial usage of RVecs inside RDF code.