[ruby-core:118297] [Ruby master Bug#20521] Memory leak in Ripper parsing

11 Jun 2024

      Issue #20521 has been updated by k0kubun (Takashi Kokubun).

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

ruby_3_3 commit:23f4b78ad8844ec81cb02fad25a6247a2d498582 merged revision(s) 27321290.

----------------------------------------
Bug #20521: Memory leak in Ripper parsing
https://bugs.ruby-lang.org/issues/20521#change-108802

* Author: kddnewton (Kevin Newton)
* Status: Closed
* Backport: 3.1: DONTNEED, 3.2: DONTNEED, 3.3: DONE
----------------------------------------
Currently, this code is leaking:

```ruby
require "ripper"

source = <<~'RUBY'
<<-A; %w[j\
i
A
j]
RUBY

10.times do
  100_000.times do
    Ripper.sexp_raw(source)
  end

  puts `ps -o rss= -p #{$$}`
end
```

This results in:

```
 31584
 36304
 41504
 47008
 51712
 56384
 61088
 65792
 70480
 75200
```

I haven't managed to track it down, but I can see that 3.2.2 does not leak but 3.3.0 does leak.

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