Feature #16755: warning: `if' at the end of line without an expression

• Status: Open
• Assignee: -
• Target version: -

[mpapis (Michal Papis)]

I'm using this notation in a lot of scripts:

if
  true
then
  puts :a
else
  puts :b
end

Using ruby 2.6.5 I'm getting expected response:

(0) 2.6.5 mpapis@mpapis-linux:~/tmp>ruby -w test.rb 
a

Using ruby 2.7.1 I'm getting extra warning:

(0) 2.7.1 mpapis@mpapis-linux:~/tmp>ruby -w test.rb 
test.rb:1: warning: `if' at the end of line without an expression
a

I've tracked it to the following git commits:

• ba35c14325ebbf1da8f200df83c45ee9937ff8a1
• c303854e134043d905baff2385add44cc2c28756
• 26316cc350109ba71d42f944f3b976985627c042
• e91e3274bebc803b97971ad0a6f4ee3a8c646a60
• a087e027bf7cf0fbb825f1d55668f85ab1f3c9e6
• 30a74aaef00a99364f5423439ac44babf5066dc0

[jeremyevans0 (Jeremy Evans)]

• ruby -v deleted (ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-linux])
• Backport deleted (2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN)
• Tracker changed from Bug to Feature

As you can see from the commit message in ba35c14325ebbf1da8f200df83c45ee9937ff8a1, this is a new feature and expected behavior in Ruby 2.7, though it may still be considered experimental.

You can filter the warnings by overriding Warning.warn, or using the warning gem:

require 'warning'
Warning.ignore(/`(els)?if' at the end of line without an expression/)

As the current behavior is now expected, this isn't a bug, so I'm switching this to a feature request to remove the warning.

[shevegen (Robert A. Heiler)]

You can filter the warnings by overriding Warning.warn, or using the warning gem:

require 'warning'
Warning.ignore(/`(els)?if' at the end of line without an expression/)

That's pretty cool! I did not know that was possible in quite that way. Learned
something there. :D

[Removed stuff here.]

Edit: Aaah yikes ... I misread your comment; you referred to the warning gem. I
thought this was part of ruby as-is. Well, still cool that this exists at the
least.