From: markus.doits@... Date: 2016-01-07T14:36:35+00:00 Subject: [ruby-core:72764] [Ruby trunk - Bug #11967] Mixing kwargs with optional parameters changes way method parameters are parsed Issue #11967 has been updated by Markus Doits. Subject changed from Mixing kwargs with optional parameters change way method parameters are parsed to Mixing kwargs with optional parameters changes way method parameters are parsed ---------------------------------------- Bug #11967: Mixing kwargs with optional parameters changes way method parameters are parsed https://bugs.ruby-lang.org/issues/11967#change-56009 * Author: Markus Doits * Status: Open * Priority: Normal * Assignee: * ruby -v: ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-darwin15] * Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN, 2.3: UNKNOWN ---------------------------------------- I have the following method: def test(first_param = nil, keyword_arg: nil) puts "first_param: #{first_param}" puts "keyword_arg: #{keyword_arg}" end All the following calls do what I expect them to do: test(:something) #=> first_param: something # keyword_arg: test(nil, keyword_arg: :keyword_arg) #=> first_param: # keyword_arg: keyword_arg test({ first_param: :is_a_hash }, keyword_arg: :is_still_working) #=> first_param: {:first_param=>:is_a_hash} # keyword_arg: is_still_working But omitting the optional `keyword_arg` and passing a hash as first argument gives me an error: test(first_param: :is_a_hash) #=> test.rb:1:in `test': unknown keyword: first_param (ArgumentError) # from test.rb:12:in `
' I'd expect it to set `first_param` to `{ first_param: :is_hash }` and `keyword_arg` being `nil`. It seems it is interpreting every hash as keyword arg: test(keyword_arg: :should_be_first_param) #=> first_param: # keyword_arg: should_be_first_param This should have set `first_param` to `{ keyword_arg: :should_be_first_param }`, leaving `keyword_arg` `nil` in my opinion. Making the first parameter *mandatory* and everything works like I'd expect to: def test(first_param, keyword_arg: nil) puts "first_param: #{first_param}" puts "keyword_arg: #{keyword_arg}" end test(first_param: :is_a_hash) #=> first_param: {:first_param=>:is_a_hash} # keyword_arg: test(keyword_arg: :should_be_first_param) #=> first_param: {:keyword_arg=>:should_be_first_param} #=> keyword_arg: I'd expect making a parameter optional does not change the way parameters are parsed. Is this a parser oddity or expected behaviour? -- https://bugs.ruby-lang.org/ Unsubscribe: