Classes derived from detail::buffer<T> declare non-virtual destructors

[BartSiwek]

Compiling with gcc (GCC) 10.2.1 and -Werror=non-virtual-dtor:

error: ‘class fmt::v7::detail::counting_buffer<>’ has virtual functions and accessible non-virtual destructor [-Werror=non-virtual-dtor]
...
error: ‘class fmt::v7::basic_memory_buffer<wchar_t>’ has virtual functions and accessible non-virtual destructor [-Werror=non-virtual-dtor]

[mwinterb]

See this comment: #1934 (comment)
But, it looks like making counting_buffer, basic_memory_buffer, etc. final addresses the warning in a proper way, if that's appropriate for those types: https://gcc.godbolt.org/z/7sb694.

[BartSiwek]

Thanks for the answer. While I understand that a decision has been made it makes using fmt in codebases who have that warning on (an warnings as errors) very difficult.
I can make a PR that adds the final keyword if that is the desired direction.

[BartSiwek]

And here is the PR #1937

[madscientist]

To me, this change is a mistake. There's nothing wrong with not having a virtual destructor here and I think it's incorrect that the compiler warns about it like this.

Meanwhile not being able to subclass these is a real loss in functionality IMO.

Anyway, my $0.02. Cheers!