Bug #20094: Inline while loop behavior changed unexpectedly in 3.3.0

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: 3.3.0
• Backport: 3.0: UNKNOWN, 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONE

[sisyphus_cg (Sisyphus CG)]

The behavior of the inline while loop has changed in 3.3.0. This unexpectedly broke my code and I couldn't find anything in the changelog about it so reporting it as a bug.

In ruby <= 3.2:

(p 1) while false      # nothing
(p 1; p 2) while false # nothing

In ruby 3.3:

(p 1) while false      # 1
(p 1; p 2) while false # 1 2

Essentially, if the left hand side looks like a statement, now it is treated as a do-while loop. In ruby 3.2 and less this only happened with explicit use of begin and end.

[nobu (Nobuyoshi Nakada)]

https://github.com/ruby/ruby/pull/9373

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Closed

Fixed by bc002971b6ad483dbf69b8a275c44412bb6ab954

[jeremyevans0 (Jeremy Evans)]

• Backport changed from 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN to 3.0: UNKNOWN, 3.1: DONTNEED, 3.2: DONTNEED, 3.3: REQUIRED

[naruse (Yui NARUSE)]

• Backport changed from 3.0: UNKNOWN, 3.1: DONTNEED, 3.2: DONTNEED, 3.3: REQUIRED to 3.0: UNKNOWN, 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONE

ruby_3_3 119d447d42d4645ac919ee53f3ec294deaa7c59b merged revision(s) bc002971b6ad483dbf69b8a275c44412bb6ab954.

[rbjl (Jan Lelis)]

It seems like the bug is still present in Ruby 3.3.1:

(p 1) while false # 1

[Eregon (Benoit Daloze)]

Indeed:

$ ruby -ve '(p 1) while false'
ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux]
$ ruby -ve '(p 1) while false'
ruby 3.3.1 (2024-04-23 revision c56cd86388) [x86_64-linux]
1