From: "eightbitraptor (Matthew Valentine-House)" <noreply@...>
Date: 2022-12-06T18:27:50+00:00
Subject: [ruby-core:111222] [Ruby master Bug#19167] Object#inspect does not correctly show NilClass TrueClass and FalseClass stored in instance variables

Issue #19167 has been updated by eightbitraptor (Matthew Valentine-House).

File 0001-Fix-Object-inspect-with-NilClass-as-an-ivar.patch added

tompng (tomoya ishida) wrote:
> ~~~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]>
> ~~~

This is exhibiting the same behaviour on the `master` branch.

This looks to be happening because `inspect_i` from `object.c` gets called for each instance variable, and that is using the `PRIsVALUE` macro to print out the values, whereas when we inspect the array in `@e` we use `rb_ary_inspect` which prints each element using `rb_inspect`, and the behaviour of these two differs when being used on `NilClass` and `TrueClass`

I agree that this seems like unintended behaviour, and I've attached a possible patch. I haven't yet investigated fully how `PRIsVALUE` works - so my solution may not be the correct one, nor have I investigated whether there is any performance overhead to using `rb_inspect` in the `inspect_i` case.



----------------------------------------
Bug #19167: Object#inspect does not correctly show NilClass TrueClass and FalseClass stored in instance variables
https://bugs.ruby-lang.org/issues/19167#change-100512

* 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)


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