Bug #15872: CSV.parse omits close call when block is given – intended or bug?

• Status: Rejected
• Assignee: kou (Kouhei Sutou)
• Target version: -
• Backport: 2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN

[sos4nt (Stefan Schüßler)]

The current implementation of CSV.parse doesn't call close when a block is given:

def self.parse(*args, &block)
  csv = new(*args)

  return csv.each(&block) if block_given?

  begin
    csv.read
  ensure
    csv.close  # <- never gets here if block is given
  end
end

A possible fix would be:

def self.parse(*args, &block)
  csv = new(*args)
  if block_given?
    csv.each(&block) 
  else
    csv.read
  end
ensure
  csv.close
end

But I'm not sure if this behavior might be intended, given that Ruby's CSV library is quite mature.

Am I missing a use case or is this actually a bug?

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Rejected

When a block is given and the argument is an IO-like object, it may not reach its end after exiting the each method.

[kou (Kouhei Sutou)]

• Assignee set to kou (Kouhei Sutou)

CSV.parse expects a String as the input. So close isn't necessary.

If you have a problem case, could you report this with the problem case to https://github.com/ruby/csv/issues ?

[marcandre (Marc-Andre Lafortune)]

FWIW, I believe this is a bug.

When a block is given and the argument is an IO-like object, it may not reach its end after exiting the each method

You mean if the block interrupts the processing with break, return or raise? Maybe it should close it in those cases (I think it still should), but for the normal case it should definitely close the IO when exiting normally.

CSV.parse expects a String as the input

This is incorrect. CSV methods expect a String or an IO.

If you have a problem case, could you report this with the problem case to https://github.com/ruby/csv/issues ?

Is there information anywhere about where to file issues? I find it quite inconvenient for users to have to move issues here and there... An issue filed on github recently had a comment to file it here, now here is the contrary...