Bug #14062: Top-level return allows an argument

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.5.0dev (2017-10-26 trunk 60450) [x86_64-linux]
• Backport: 2.3: UNKNOWN, 2.4: UNKNOWN

[Eregon (Benoit Daloze)]

puts "Here"
return 42 # or :foo, or any value

ruby test.rb
Here

Should it be a SyntaxError, as mentioned in https://bugs.ruby-lang.org/issues/4840#note-24 ?
It seems confusing to accept it silently, as one could expect the exit code to be affected by it (that should not be the case imho).

Discovered in https://github.com/ruby/spec/pull/530

[duerst (Martin Dürst)]

Wouldn't this be equivalent to C's return statement in main()?

It is used to tell the outer process (usually a shell) about the success (0) or failure (anything else than 0) of the program.

In the average shell, you should be able to test it with e.g.

ruby test.rb && echo "Previous process was successful."

which would not print the "Previous process was successful." text because the return value was something else than 0.

[Eregon (Benoit Daloze)]

Currently the argument is ignored.
And I think it would make little sense in a file loaded by #require to affect the global exit status if it does a "return 1".
"exit 1" can be used for that, top-level return is to avoid loading anything further in the file when it's not needed in my understanding.

[matz (Yukihiro Matsumoto)]

• Related to Feature #4840: Allow returning from require added

[matz (Yukihiro Matsumoto)]

I am against making it a syntax error. Adding warnings is OK (but maybe we can rely on Rubocop etc. to detect them).

Matz.

[jeremyevans0 (Jeremy Evans)]

• File top-level-return-warn-argument.patch top-level-return-warn-argument.patch added

Attached is a patch that adds a warning when using a top-level return with an argument.

[Eregon (Benoit Daloze)]

• Description updated (diff)

[Eregon (Benoit Daloze)]

jeremyevans0 (Jeremy Evans) wrote:

Attached is a patch that adds a warning when using a top-level return with an argument.

Thank you, it looks good to me.
Although, I would suggest to change the warning message to one of these:

argument of top-level return is ignored
argument of return at top-level is ignored

Could you commit it?

• Status changed from Open to Closed

Applied in changeset git|aa97410b0a85cb4ceb956ab943b5eee92a128411.

---

Warn if using return at top-level with an argument

Fixes [Bug #14062]