Re: [PATCH] Complete __gnu_debug::basic_string Standard conformity

["François Dumont" <frs.dumont@gmail.com>]

On 19/07/22 12:42, Jonathan Wakely wrote:
> On Sun, 10 Jul 2022 at 14:57, François Dumont via Libstdc++
> <libstdc++@gcc.gnu.org> wrote:
>> Here is a first patch to complete __gnu_debug::basic_string Standard
>> conformity.
>>
>> I prefer to submit this before checking for more missing stuff to check
>> that my proposal of having a testsuite_string.h header is ok.
> I think this change means some testcases will never test std::string
> with _GLIBCXX_DEBUG defined, because if that is defined they test
> __gnu_debug::string instead. That means assertions in
> std::basic_string like this one will not get tested:
>
>    template<typename _CharT, typename _Traits, typename _Alloc>
>      _GLIBCXX_STRING_CONSTEXPR
>      typename basic_string<_CharT, _Traits, _Alloc>::size_type
>      basic_string<_CharT, _Traits, _Alloc>::
>      find(const _CharT* __s, size_type __pos, size_type __n) const
>      _GLIBCXX_NOEXCEPT
>      {
>        __glibcxx_requires_string_len(__s, __n);
>
> Are we OK with never testing those assertions?

> Currently they don't get tested by default because of the extern
> template declarations for std::string, so they would only be tested
> with -std=c++20 -D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC, which I
> don't test routinely. So I suppose this change doesn't make things any
> worse in practice.
Good point, I'll try to activate those asserts with just 
_GLIBCXX_ASSERTIONS so that we will still be able to test despite my change.
>> I also noticed some problems with _GLIBCXX_DEBUG_PEDANTIC.
>>
>>       libstdc++: Complete __gnu_debug::string Standard conformity
>>
>>       Add testsuite/testsuite_string.h header to help testing
>> __gnu_debug::basic_string like
>>       std::basic_string depending on _GLIBCXX_DEBUG.
>>
>>       Add using of base type methods in __gnu_debug::basic_string to make
>> use of the method
>>       overloads when there is no debug version.
>>
>>       Fix _GLIBCXX_DEBUG_PEDANTIC assertions in <debug/string>. This
>> header has to be used directly
>>       like __gnu_debug::string, it is not included by _GLIBCXX_DEBUG. It
>> means that
>>       _GLIBCXX_DEBUG_PEDANTIC is not considered to define
>> __glibcxx_check_string and
>>       __glibcxx_check_string_len which are then empty macros. Now those
>> macros are defined
>>       directly in <debug/string> and properly consider
>> _GLIBCXX_DEBUG_PEDANTIC.
> Nice catch.

Yes, I forgot to signal that before this patch some tests were XFAIL in 
segfault rather than with the proper _GLIBCXX_DEBUG_PEDANTIC assertion.


>
> OK for trunk, thanks.
>
Ok, committed.