From: "Eregon (Benoit Daloze)" <noreply@...>
Date: 2022-01-28T13:29:54+00:00
Subject: [ruby-core:107322] [Ruby master Bug#18518] NoMemoryError + [FATAL] failed to allocate memory for twice 1 << large

Issue #18518 has been updated by Eregon (Benoit Daloze).


Actually I'm not sure this is properly fixed on 3.1.0, it looks brittle, for instance it fails in GitHub Actions on macOS:
https://github.com/ruby/spec/runs/4981061444?check_suite_focus=true

NoMemoryError might also be a bit weird for this.
How about raising RangeError or TypeError for any exponent which does not fit in an `int`?
Such cases don't make much sense anyway.

----------------------------------------
Bug #18518: NoMemoryError + [FATAL] failed to allocate memory for twice 1 << large
https://bugs.ruby-lang.org/issues/18518#change-96220

* Author: Eregon (Benoit Daloze)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [x86_64-linux]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
Repro:
```ruby
exp = 2**40 # also fails with bignum e.g. 2**64

def exc
  begin
    yield
  rescue NoMemoryError => e
    p :NoMemoryError
  end
end

p exp
exc { (1 << exp) }
exc { (-1 << exp) }
exc { (bignum_value << exp) }
exc { (-bignum_value << exp) }
```

Output:
```
$ ruby -v mri_oom.rb
ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [x86_64-linux]
mri_oom.rb:7: warning: assigned but unused variable - e
1099511627776
:NoMemoryError
[FATAL] failed to allocate memory
```

3.1.0 seems fine:
```
$ ruby -v mri_oom.rb
ruby 3.1.0p0 (2021-12-25 revision fb4df44d16) [x86_64-linux]
mri_oom.rb:7: warning: assigned but unused variable - e
1099511627776
:NoMemoryError
:NoMemoryError
:NoMemoryError
:NoMemoryError
```



-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>