Regression #open method for writing from Ruby 2.4.3 to 2.5.0 #17
Description
I have noticed a different behaviour between Ruby <= 2.4.3 and Ruby 2.5.0 for the #open method.
If you create an empty file for writing and you are not writing any line in that CSV file, Ruby <= 2.4.3 doesn't write anything (an empty file) but Ruby 2.5.0 writes the headers.
Ruby <= 2.4.3
$ ruby -v
ruby 2.4.3p205 (2017-12-14 revision 61247) [x86_64-darwin17]$ irb
irb(main):001:0> require "csv"
=> true
irb(main):002:0> CSV.open("ruby-2.4.3.csv", "wb", headers: ["name", "surname"], write_headers: true) { }
=> nil
irb(main):003:0> `cat ruby-2.4.3.csv`
=> ""Ruby 2.5.0
$ ruby -v
ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-darwin17]$ irb
irb(main):001:0> require "csv"
=> true
irb(main):002:0> CSV.open("ruby-2.5.0.csv", "wb", headers: ["name", "surname"], write_headers: true) { }
=> nil
irb(main):003:0> `cat ruby-2.5.0.csv`
=> "name,surname\n"In the examples, I'm using an empty block but in a real application probably you will have an if statement, something like this:
CSV.open(...) do |csv|
csv << "hello" if condition
end