Bug #15758: Object.const_defined?(name) falsely returns true on classes that are not defined - Ruby master - Ruby Issue Tracking System

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Bug #15758

closed

Object.const_defined?(name) falsely returns true on classes that are not defined

Added by dux (Dino Reic) over 5 years ago. Updated almost 5 years ago.

Status:

Closed

Assignee:

Target version:

ruby -v:

2.6.2, 2.7.0-dev

Backport:

2.4: DONTNEED, 2.5: DONTNEED, 2.6: DONE

[ruby-core:92202]

Description

in short https://i.imgur.com/qvIIBuu.png

Object.const_defined?('Baz::Bar') -> true

yet Baz::Bar -> class not found!

test to run, all ok on ruby 2.6.0, bug in 2.6.2

class Foo
end

class Bar
end

class Baz
  class Foo
  end
end

###

def report klass
  name     = "Object.const_defined?('%s')" % klass
  exists   = Object.const_defined?(klass)
  instance = eval klass rescue nil
  check    = (exists && instance) || (!exists && !instance)? 'ok' : 'ERROR!'

  puts [
    name.ljust(35),
    exists.to_s.ljust(5),
    (instance ? instance.to_s : 'nil').ljust(8),
    check
  ].join(' -> ')
end

report 'Foo'
report 'Bar'
report 'Baz'
report 'Naat'
report 'Baz::Foo'
report 'Baz::Bar'
report 'Baz::Naat'
puts   '---'
report 'Baz::Foo::Bar::Baz::Foo' # true in 2.6.2 :)

running produces output

Object.const_defined?('Foo')        -> true  -> Foo      -> ok
Object.const_defined?('Bar')        -> true  -> Bar      -> ok
Object.const_defined?('Baz')        -> true  -> Baz      -> ok
Object.const_defined?('Naat')       -> false -> nil      -> ok
Object.const_defined?('Baz::Foo')   -> true  -> Baz::Foo -> ok
Object.const_defined?('Baz::Bar')   -> true  -> nil      -> ERROR!
Object.const_defined?('Baz::Naat')  -> false -> nil      -> ok
---
Object.const_defined?('Baz::Foo::Bar::Baz::Foo') -> true  -> nil      -> ERROR!

Files

bug.rb (581 Bytes) bug.rb

dux (Dino Reic), 04/08/2019 11:27 AM

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