Bug #20731: warning: mismatched indentations at 'when' appears with prism enabled ruby

• Status: Closed
• Assignee: kddnewton (Kevin Newton)
• Target version: -
• ruby -v: ruby 3.4.0dev (2024-09-12T20:03:28Z master 0fc8422a05) +PRISM [x86_64-linux]
• Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN

[yahonda (Yasuo Honda)]

Steps to reproduce

1. Create a case_sample.rb file

foo = :bar
case foo
  when :bar
    p 'foo is :bar'
  when :baz
    # do something
  else
    # do something
end

2. Run this file against the latest Ruby 3.4.0dev with -w option to show warnings

$ ruby -w case_sample.rb

Expected behavior

It should show "foo is :bar" without any warnings as it runs against Ruby 3.3.5 or Ruby 3.4.0dev before prism is used by default

$ ruby -w case_sample.rb
"foo is :bar"
$ ruby -v
ruby 3.3.5 (2024-09-03 revision ef084cc8f4) [x86_64-linux]
$

$ ruby -w case_sample.rb
"foo is :bar"
$ ruby -v
ruby 3.4.0dev (2024-09-12T17:04:10Z master f2919bd11c) [x86_64-linux]
$

Actual behavior

It raises warning: mismatched indentations at 'when' with 'case' warnings as follows.

$ ruby -w case_sample.rb
case_sample.rb:3: warning: mismatched indentations at 'when' with 'case' at 2
case_sample.rb:5: warning: mismatched indentations at 'when' with 'case' at 2
"foo is :bar"
$ ruby -v
ruby 3.4.0dev (2024-09-12T20:03:28Z master 0fc8422a05) +PRISM [x86_64-linux]
$

Background

This repro is based on the tzinfo code below.

https://github.com/tzinfo/tzinfo/blob/d5893c99bbcd842af86023f02a84fac1659b3031/lib/tzinfo/timestamp.rb#L115-L127
https://github.com/tzinfo/tzinfo/blob/d5893c99bbcd842af86023f02a84fac1659b3031/lib/tzinfo/timestamp.rb#L147-L154

[hsbt (Hiroshi SHIBATA)]

I also have similar issues with rss.

/Users/hsbt/Documents/github.com/ruby/ruby/gems/src/rss/lib/rss/1.0.rb:81: warning: mismatched indentations at ‘else’ with ‘if’ at 79
(snip)

https://github.com/ruby/rss/blob/master/lib/rss/1.0.rb#L81 is seems correct for me.

[mame (Yusuke Endoh)]

The wrong warning with rss gem is a different issue. I have created a separate ticket #20732.

[hsbt (Hiroshi SHIBATA)]

@mame (Yusuke Endoh)

Thanks!

[hsbt (Hiroshi SHIBATA)]

• Status changed from Open to Assigned
• Assignee set to kddnewton (Kevin Newton)

[kddnewton (Kevin Newton)]

I have opened https://github.com/ruby/ruby/pull/11620 to fix this.

[kddnewton (Kevin Newton)]

• Status changed from Assigned to Closed