Issue #19167 has been updated by alanwu (Alan Wu). Currently it's using a format string with `"%+"PRIsVALUE`, which calls rb_inspect() for most values, but with special-case handling for a NilClass and friends. The special handling was introduced in commit:4191a6b90d3eeb63a31609dba29a1904efee3738: ```diff diff --git a/sprintf.c b/sprintf.c index 4549791d2029e..afe27c2d63ae3 100644 --- a/sprintf.c +++ b/sprintf.c @@ -1338,6 +1338,26 @@ ruby__sfvextra(rb_printf_buffer *fp, size_t valsize, void *valp, long *sz, int s rb_raise(rb_eRuntimeError, "rb_vsprintf reentered"); } if (sign == '+') { + if (RB_TYPE_P(value, T_CLASS)) { +# define LITERAL(str) (*sz = rb_strlen_lit(str), str) + + if (value == rb_cNilClass) { + return LITERAL("nil"); + } + else if (value == rb_cFixnum) { + return LITERAL("Fixnum"); + } + else if (value == rb_cSymbol) { + return LITERAL("Symbol"); + } + else if (value == rb_cTrueClass) { + return LITERAL("true"); + } + else if (value == rb_cFalseClass) { + return LITERAL("false"); + } +# undef LITERAL + } value = rb_inspect(value); ``` The commit is titled "preserve encodings in error messages", and none of the other changes use the `+` modifier. Maybe the special handling was added by accident? ---------------------------------------- Bug #19167: Object#inspect does not correctly show NilClass TrueClass and FalseClass stored in instance variables https://bugs.ruby-lang.org/issues/19167#change-100514 * Author: tompng (tomoya ishida) * Status: Open * Priority: Normal * ruby -v: ruby 3.1.0p0 (2021-12-25 revision fb4df44d16) [x86_64-darwin20] * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- ~~~ruby Object.new.instance_eval do @a = nil @b = NilClass @c = true @d = TrueClass @e = [nil, NilClass, true, TrueClass] puts self.inspect end # actual # => #<Object:0x2f15e3c8 @a=nil, @b=nil, @c=true, @d=true, @e=[nil, NilClass, true, TrueClass]> # expected # => #<Object:0x2f15e3c8 @a=nil, @b=NilClass, @c=true, @d=TrueClass, @e=[nil, NilClass, true, TrueClass]> ~~~ ---Files-------------------------------- 0001-Fix-Object-inspect-with-NilClass-as-an-ivar.patch (751 Bytes) -- https://bugs.ruby-lang.org/