https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124051
Bug ID: 124051
Summary: forward_list::sort is not exception-safe
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: ensadc at mailnesia dot com
Target Milestone: ---
https://godbolt.org/z/aGPnK41Kr
====
#include <forward_list>
int main() {
std::forward_list<int> mylist{5, 4, 3, 2};
try {
int i = 0;
mylist.sort([&](int a, int b) {
if (++i == 2) throw 42;
return a < b;
});
} catch (...) {} // crash
}
====
[forward.list.ops]/29 says "Effects: Sorts the list according to the operator<
or the comp function object. If an exception is thrown, the order of the
elements in *this is unspecified. Does not affect the validity of iterators and
references."
This seems to suggest that `forward_list::sort` should provide basic exception
guarantee, instead of breaking the class invariants when the comparator throws.
