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Unable to define == for objects when using Array#delete #6262
Description
Defining == method on an object so that it's used for comparison when using Array#delete causes an exception. For some reason, the other becomes an Object, rather than Cell.
Sample code
class Cell
attr_accessor :id
def initialize
@id = rand(1_000_000)
end
def ==(other)
@id == other.id
end
def id
@id
end
end
cells = Array.new(1_000) { Cell.new }
1_000.times do |i|
cells.delete(cells.sample)
end
puts "There are #{cells.size} cells left."Expected
$ mruby test.rb
There are 0 cells left.
Actual
$ mruby test.rb
trace (most recent call last):
[2] mruby.rb:18
[1] mruby.rb:19
test.rb:9:in ==: undefined method 'id' (NoMethodError)
Activity
phi-luna commentedon May 9, 2024
this error seems to not occur at current master (19d9f48)
it seems to have been fixed by 14bd875
pusewicz commentedon May 9, 2024
@leviongit I played around, and in fact it's an issue with the
Array#index:Expected
Actual
mruby-enum-ext: use NONE.equal?() for NONE comparison; ref #6262
mruby-enumerator: use NONE.equal?() for NONE comparison; ref #6262
mruby-hash-ext: use NONE.equal?() for NONE comparison; ref #6262
matz commentedon May 10, 2024
As general advice, the
==method should accept any object as an argument. But we fixed the issue anyway.mruby-array-ext: use NONE.equal?() for NONE comparison; fix mruby#6262
pusewicz commentedon May 12, 2024
@matz That's correct, but in my case I knew exactly that there would be only one type of object in the array.
matz commentedon May 13, 2024
Despite of your expectation
==method may be called from the library. In fact, the bug was in thefindmethod calling==.