Write a byte escape in upper case hex, as CRuby does - #7145

String#inspect and String#dump write a byte that spells no character as \xNN, and mruby spells the two digits in lower case where CRuby spells them in upper case:

171.chr.inspect  #=> "\"\\xAB\"" in CRuby, "\"\\xab\"" in mruby
"る".dump        #=> "\"\\xE3\\x82\\x8B\"" in CRuby, lower case in mruby

str_escape() takes the two digits from mrb_digitmap, the table Integer#to_s reads a number through. Lower case is right for that table, since CRuby spells a number in lower case as well, so the escape gets a table of its own rather than the shared one moving under both readers.

What moves with it

Everything that prints through str_escape(): String#inspect, String#dump, Symbol#inspect of a name that has to be quoted, and the %! conversions of mrb_vformat(), which is what the debugger's p prints through.

What stays

mrb_ptr_to_str() keeps mrb_digitmap, since CRuby writes the address in #<Object:0x...> in lower case too. %X in mruby-sprintf upper cases its own output through toupper() and never reads the table.

Tests

The first commit moves every expectation that pinned the lower case spelling, and gives String#inspect a case of a single byte above ASCII, which it had none of. It fails without the second.

Five places held such an expectation: core String#inspect and mrb_vformat, mruby-string-ext's String#dump and its inspect of a byte-read string, mruby-encoding's Integer#chr above ASCII, and mruby-bin-debugger's bintest for p.

Verification

At the tip, the full suite is green on ci/gcc-clang in full, which is full-debug, bintest, cxx_abi and the default gembox build, and on the plain host build. 0 failures, 0 crashes. The bintest run is included, since the debugger's p prints through this escape.

Summary by CodeRabbit

• Bug Fixes
  • Updated string inspection, dumping, and formatting to use uppercase hexadecimal escapes, such as \xAB, for non-printable and binary characters.
  • Standardized escape output across regular, formatted, UTF-8, and non-UTF-8 strings.