Bug #16086: OpenStruct method access with a block does not raise

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 2.5: UNKNOWN, 2.6: UNKNOWN

[kke (Kimmo Lehto)]

This can cause confusion.

  > OpenStruct.new(hello: 'world').each { |k, v| puts k.upcase } # there's no "each" method
  => nil
  > OpenStruct.new(hello: 'world').eahc_pair { |k, v| puts k.upcase } # each_pair typo
  => nil

An undefined key with a block should maybe raise NoMethodError or ArgumentError?

A defined key with a block seems to yield the value, I don't see this being documented:

  > OpenStruct.new(hello: 'world').hello { |k| puts k.upcase } 
  HELLO

Maybe it should raise ArgumentError too?

Related: https://bugs.ruby-lang.org/issues/15515

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Feedback

kke (Kimmo Lehto) wrote:

This can cause confusion.

  > OpenStruct.new(hello: 'world').each { |k, v| puts k.upcase } # there's no "each" method
  => nil
  > OpenStruct.new(hello: 'world').eahc_pair { |k, v| puts k.upcase } # each_pair typo
  => nil

An undefined key with a block should maybe raise NoMethodError or ArgumentError?

That is OpenStruct, an undefined key does not raise an exception.
And an unused block is silently ignored in common.

A defined key with a block seems to yield the value, I don't see this being documented:

  > OpenStruct.new(hello: 'world').hello { |k| puts k.upcase } 
  HELLO

Maybe it should raise ArgumentError too?

I haven't seen such behavior.

$ ruby -rostruct -e 'p OpenStruct.new(hello: "world").hello { |k| puts k.upcase }'
"world"

[kke (Kimmo Lehto)]

That is OpenStruct, an undefined key does not raise an exception.
And an unused block is silently ignored in common.

Right, this behavior seems to be universal:

> { foo: :bar }[:foo] { 'hello' }
=> :bar
> 1.abs { 'hello' }
=> 1

I haven't seen such behavior.

$ ruby -rostruct -e 'p OpenStruct.new(hello: "world").hello { |k| puts k.upcase }'
"world"

Hmm, I can't replicate it anymore either. I must have been experimenting with each_pair.

I guess nothing in this issue is actually an issue and it can be closed. This came from frustration when I assumed there was an each method and all I got was nil and couldn't figure out why.

[kke (Kimmo Lehto)]

• Status changed from Feedback to Closed