[ruby-core:109879] [Ruby master Bug#19004] Complex can be nested by Complex.polar

[ruby-core:109879] [Ruby master Bug#19004] Complex can be nested by Complex.polar

[msnm (Masahiro Nomoto)]

Issue #19004 has been reported by msnm (Masahiro Nomoto).

----------------------------------------
Bug #19004: Complex can be nested by Complex.polar
https://bugs.ruby-lang.org/issues/19004

* Author: msnm (Masahiro Nomoto)
* Status: Open
* Priority: Normal
* ruby -v: 3.1.2
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
`Complex.polar` with one argument can return a "nested" Complex instance, whose real part is also a Complex one.

```ruby
puts RUBY_DESCRIPTION
# ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]

p Complex.polar(1+0i)
# ((1+0i)+0i)

p 5.times.inject(1) { |num, _| Complex.polar(num) }
# (((((1+0i)+0i)+0i)+0i)+0i)
```

In Ruby < 2.7 , it simply raises an error when the argument is an instance of Complex (i.e. `obj.real? == false`).

```ruby
puts RUBY_DESCRIPTION
# ruby 2.6.10p210 (2022-04-12 revision 67958) [x86_64-linux]

p Complex.polar(1+0i)
# TypeError (not a real)
```




-- 
https://bugs.ruby-lang.org/

[ruby-core:110322] [Ruby master Bug#19004] Complex can be nested by Complex.polar

[stevegeek (Stephen Ierodiaconou)]

Issue #19004 has been updated by stevegeek (Stephen Ierodiaconou).


I thought to try fixing this issue as a first contribution to Ruby. I have a proposed fix here https://github.com/ruby/ruby/pull/6568 

Details are on the PR, but in summary, I believe that the ability to pass a Complex as the abs argument is the expected behaviour (given other methods on Complex also accept Complex value as long as they are real, in the sense they have a zero imaginary part). However Complex.polar with a single argument creates the new Complex without first extracting the real part of the argument, so `Complex.polar(1+0.0i).real` => (1+0i) 

The propose fix simply ensures that the single argument case is handled in the same way as the 2 argument case, so `Complex.polar(1+0.0i).real` => 1 

----------------------------------------
Bug #19004: Complex can be nested by Complex.polar
https://bugs.ruby-lang.org/issues/19004#change-99616

* Author: msnm (Masahiro Nomoto)
* Status: Open
* Priority: Normal
* ruby -v: 3.1.2
* Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
`Complex.polar` with one argument can return a "nested" Complex instance, whose real part is also a Complex one.

```ruby
puts RUBY_DESCRIPTION
# ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]

p Complex.polar(1+0i)
# ((1+0i)+0i)

p 5.times.inject(1) { |num, _| Complex.polar(num) }
# (((((1+0i)+0i)+0i)+0i)+0i)
```

In Ruby < 2.7 , it simply raises an error when the argument is an instance of Complex (i.e. `obj.real? == false`).

```ruby
puts RUBY_DESCRIPTION
# ruby 2.6.10p210 (2022-04-12 revision 67958) [x86_64-linux]

p Complex.polar(1+0i)
# TypeError (not a real)
```




-- 
https://bugs.ruby-lang.org/

[ruby-core:110614] [Ruby master Bug#19004] Complex can be nested by Complex.polar

[nagachika (Tomoyuki Chikanaga)]

Issue #19004 has been updated by nagachika (Tomoyuki Chikanaga).

Backport changed from 2.7: REQUIRED, 3.0: REQUIRED, 3.1: REQUIRED to 2.7: REQUIRED, 3.0: REQUIRED, 3.1: DONE

ruby_3_1 597ce7966c38e4f7fc7368a860ac2d056de794ba merged revision(s) 54cad3123a07583c90e85bcfc55ebd87124c1250.

----------------------------------------
Bug #19004: Complex can be nested by Complex.polar
https://bugs.ruby-lang.org/issues/19004#change-99946

* Author: msnm (Masahiro Nomoto)
* Status: Closed
* Priority: Normal
* ruby -v: 3.1.2
* Backport: 2.7: REQUIRED, 3.0: REQUIRED, 3.1: DONE
----------------------------------------
`Complex.polar` with one argument can return a "nested" Complex instance, whose real part is also a Complex one.

```ruby
puts RUBY_DESCRIPTION
# ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]

p Complex.polar(1+0i)
# ((1+0i)+0i)

p 5.times.inject(1) { |num, _| Complex.polar(num) }
# (((((1+0i)+0i)+0i)+0i)+0i)
```

In Ruby < 2.7 , it simply raises an error when the argument is an instance of Complex (i.e. `obj.real? == false`).

```ruby
puts RUBY_DESCRIPTION
# ruby 2.6.10p210 (2022-04-12 revision 67958) [x86_64-linux]

p Complex.polar(1+0i)
# TypeError (not a real)
```




-- 
https://bugs.ruby-lang.org/