Bug #14566: `raise` in `Exception#message` causes infinite loop

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.6.0dev (2018-03-01 trunk 62592) [x86_64-linux]
• Backport: 2.3: DONTNEED, 2.4: DONTNEED, 2.5: DONE

[pocke (Masataka Kuwabara)]

This code does not stop.

class A < StandardError
  def message
    raise
  end
end

raise A

The following code also does not stop.

class A < StandardError
  def message
    1/0
  end
end

raise A

And they ignore CTRL-C, so I should do CTRL-Z (suspend) and kill -9 to stop them.

I confirmed the problem in Ruby 2.5 and trunk.

$ ruby -v
ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-linux]

$ ruby -v
ruby 2.6.0dev (2018-03-01 trunk 62592) [x86_64-linux]

But Ruby 2.4 and 2.3 do not stop (I does not have Ruby 2.2 because I cannot build it in my environment.).
I can get same outputs between raise and 1/0 in the message method body.

$ ruby -v test.rb
ruby 2.4.3p205 (2017-12-14 revision 61247) [x86_64-linux]
test.rb:7:in `<main>': A

$ ruby -v test.rb
ruby 2.3.6p384 (2017-12-14 revision 61254) [x86_64-linux]
test.rb:7:in `<main>': A

[ujihisa (Tatsuhiro Ujihisa)]

• File fix-bug-14566.patch fix-bug-14566.patch added

I tried making a patch fixing this issue. See attached.
This patch makes the behaviour similar to the old Ruby, rescuing any exceptions in the "message" method, but also warns that an exception was automatically caught.

I'm not 100% sure if this is the solution that everyone wants. Also the test in the patch needs an update; I wasn't sure how to make sure if it's not causing infinite loop. I just left a draft as a comment there.

[nobu (Nobuyoshi Nakada)]

Thank you, I've missed the report mail.
I think it fatal.

[nobu (Nobuyoshi Nakada)]

• Backport changed from 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN to 2.3: DONTNEED, 2.4: DONTNEED, 2.5: REQUIRED

It should work as well as 2.4, not fatal.

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset trunk|r63133.

---

eval_error.c: fix loop on exception in message

• error.c (rb_get_message): accessor to the message.

• eval_error.c (rb_ec_error_print): handle exceptions on fetching
  the message. [Bug #14566]

[ujihisa (Tatsuhiro Ujihisa)]

Thx!

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.3: DONTNEED, 2.4: DONTNEED, 2.5: REQUIRED to 2.3: DONTNEED, 2.4: DONTNEED, 2.5: DONE

ruby_2_5 r64319 merged revision(s) 63133.