[ruby-core:122336] [Ruby Bug#21383] Prism leaks memory with invalid yield

29 May 2025

      Issue #21383 has been reported by peterzhu2118 (Peter Zhu).

----------------------------------------
Bug #21383: Prism leaks memory with invalid yield
https://bugs.ruby-lang.org/issues/21383

* Author: peterzhu2118 (Peter Zhu)
* Status: Open
* Backport: 3.2: DONTNEED, 3.3: DONTNEED, 3.4: REQUIRED
----------------------------------------
Fix: https://github.com/ruby/ruby/pull/13464

The following script leaks memory:

```ruby
10.times do
  20_000.times do
    eval("class C; yield; end")
  rescue SyntaxError
  end

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

Before:

```
16464
25536
29424
35904
39552
44576
46736
51600
56096
59824
```

After:

```
13488
16160
18240
20528
19760
21808
21680
22272
22064
22336
```

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