[libc++][format] Fixes default string alignment.

[Mordante]

Summary

Fixes https://llvm.org/PR58315

[Mordante]

CI fixes.

libcxx/include/__format/formatter_string.h

#  endif
 
     return __formatter::__write_string(__str, __ctx.out(), __parser_.__get_parsed_std_specifications(__ctx));
   }
 
 #  if _LIBCPP_STD_VER > 20
   _LIBCPP_HIDE_FROM_ABI constexpr void set_debug_format() { __parser_.__type_ = __format_spec::__type::__debug; }
 #  endif
 
-  __format_spec::__parser<_CharT> __parser_;
+  __format_spec::__parser<_CharT> __parser_{.__alignment_ = __format_spec::__alignment::__left};
 };
 
 // Formatter const char*.
 template <__fmt_char_type _CharT>
 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<const _CharT*, _CharT>
     : public __formatter_string<_CharT> {
   using _Base = __formatter_string<_CharT>;
 

libcxx/test/std/utilities/format/format.functions/escaped_output.ascii.pass.cpp

void test_format_functions(TestFunction check) {
   check(SV(R"("hellö"***)"), SV("{:*<{}?}"), SV("hellö"), sizeof(CharT) == 1 ? 11 : 10);
 
   check(SV("\"hello\u0308\""), SV("{:*>{}?}"), SV("hello\u0308"), sizeof(CharT) == 1 ? 9 : 8);
   check(SV("***\"hello\u0308\""), SV("{:*>{}?}"), SV("hello\u0308"), sizeof(CharT) == 1 ? 12 : 11);
   check(SV("*\"hello\u0308\"**"), SV("{:*^{}?}"), SV("hello\u0308"), sizeof(CharT) == 1 ? 12 : 11);
   check(SV("\"hello\u0308\"***"), SV("{:*<{}?}"), SV("hello\u0308"), sizeof(CharT) == 1 ? 12 : 11);
 
   // *** width ***
-  check(SV(R"(   "hello")"), SV("{:10?}"), SV("hello"));
+  check(SV(R"("hello"   )"), SV("{:10?}"), SV("hello"));
 
   // *** precision ***
   check(SV(R"("hell)"), SV("{:.5?}"), SV("hello"));
   check(SV(R"("hello)"), SV("{:.6?}"), SV("hello"));
   check(SV(R"("hello")"), SV("{:.7?}"), SV("hello"));
 
   // *** width & precision ***
   check(SV(R"("hell#########################)"), SV("{:#<30.5?}"), SV("hello"));

libcxx/test/std/utilities/format/format.functions/escaped_output.unicode.pass.cpp

void test_format_functions(TestFunction check) {
   check(SV(R"("hello\u{308}"***)"), SV("{:*<17?}"), SV("hello\u0308"));
 
   check(SV(R"("hello 🤷🏻\u{200d}♂\u{fe0f}")"), SV("{:*>10?}"), SV("hello 🤷🏻‍♂️"));
   check(SV(R"(***"hello 🤷🏻\u{200d}♂\u{fe0f}")"), SV("{:*>30?}"), SV("hello 🤷🏻‍♂️"));
   check(SV(R"(*"hello 🤷🏻\u{200d}♂\u{fe0f}"**)"), SV("{:*^30?}"), SV("hello 🤷🏻‍♂️"));
   check(SV(R"("hello 🤷🏻\u{200d}♂\u{fe0f}"***)"), SV("{:*<30?}"), SV("hello 🤷🏻‍♂️"));
 
   // *** width ***
-  check(SV(R"(   "hellö")"), SV("{:10?}"), SV("hellö"));
-  check(SV(R"(   "hello\u{308}")"), SV("{:17?}"), SV("hello\u0308"));
-  check(SV(R"(   "hello 🤷🏻\u{200d}♂\u{fe0f}")"), SV("{:30?}"), SV("hello 🤷🏻‍♂️"));
+  check(SV(R"("hellö"   )"), SV("{:10?}"), SV("hellö"));
+  check(SV(R"("hello\u{308}"   )"), SV("{:17?}"), SV("hello\u0308"));
+  check(SV(R"("hello 🤷🏻\u{200d}♂\u{fe0f}"   )"), SV("{:30?}"), SV("hello 🤷🏻‍♂️"));
 
   // *** precision ***
   check(SV(R"("hell)"), SV("{:.5?}"), SV("hellö"));
   check(SV(R"("hellö)"), SV("{:.6?}"), SV("hellö"));
   check(SV(R"("hellö")"), SV("{:.7?}"), SV("hellö"));
 
   check(SV(R"("hello )"), SV("{:.7?}"), SV("hello 🤷🏻‍♂️"));
   check(SV(R"("hello )"), SV("{:.8?}"), SV("hello 🤷🏻‍♂️")); // shrug is two columns

libcxx/test/std/utilities/format/format.functions/format_tests.h

void format_test_string(const W& world, const U& universe, TestFunction check, ExceptionTest check_exception) {
   // Unused argument is ignored. TODO FMT what does the Standard mandate?
   check(SV("hello world"), SV("hello {}"), world, universe);
   check(SV("hello world and universe"), SV("hello {} and {}"), world, universe);
   check(SV("hello world"), SV("hello {0}"), world, universe);
   check(SV("hello universe"), SV("hello {1}"), world, universe);
   check(SV("hello universe and world"), SV("hello {1} and {0}"), world, universe);
 
   check(SV("hello world"), SV("hello {:_>}"), world);
+  check(SV("hello world   "), SV("hello {:8}"), world);
   check(SV("hello    world"), SV("hello {:>8}"), world);
   check(SV("hello ___world"), SV("hello {:_>8}"), world);
   check(SV("hello _world__"), SV("hello {:_^8}"), world);
   check(SV("hello world___"), SV("hello {:_<8}"), world);
 
   check(SV("hello >>>world"), SV("hello {:>>8}"), world);
   check(SV("hello <<<world"), SV("hello {:<>8}"), world);
   check(SV("hello ^^^world"), SV("hello {:^>8}"), world);

 }
 
 template <class CharT, class TestFunction, class ExceptionTest>
 void format_test_char(TestFunction check, ExceptionTest check_exception) {
 
   // ***** Char type *****
   // *** align-fill & width ***
   check(SV("answer is '*     '"), SV("answer is '{:6}'"), CharT('*'));
-
   check(SV("answer is '     *'"), SV("answer is '{:>6}'"), CharT('*'));
   check(SV("answer is '*     '"), SV("answer is '{:<6}'"), CharT('*'));
   check(SV("answer is '  *   '"), SV("answer is '{:^6}'"), CharT('*'));
 
   check(SV("answer is '*     '"), SV("answer is '{:6c}'"), CharT('*'));
   check(SV("answer is '     *'"), SV("answer is '{:>6c}'"), CharT('*'));
   check(SV("answer is '*     '"), SV("answer is '{:<6c}'"), CharT('*'));
   check(SV("answer is '  *   '"), SV("answer is '{:^6c}'"), CharT('*'));