From: "byroot (Jean Boussier) via ruby-dev" <ruby-dev@...>
Date: 2024-03-01T07:23:05+00:00
Subject: [ruby-dev:52079]  [Ruby master Bug#20311] Struct.new("A") memory leak?

Issue #20311 has been updated by byroot (Jean Boussier).


> Is there any chance for the same module to be added twice?

Yes, aliasing isn't uncommon.

> Seems fine, but I'm afraid what can happen when an extension library stores rb_path2class("Struct::A") result then remove that constant?
Probably this is same for any Ruby-level defined classes/modules.

Yes, my reasoning is that it's not reasonable to expect classes created in Ruby to be immortal and immovable like the ones created in C.

----------------------------------------
Bug #20311: Struct.new("A") memory leak?
https://bugs.ruby-lang.org/issues/20311#change-107090

* Author: MaxLap (Maxime Lapointe)
* Status: Open
* ruby -v: 3.3.0
* Backport: 3.0: WONTFIX, 3.1: REQUIRED, 3.2: REQUIRED, 3.3: REQUIRED
----------------------------------------
The following code gives the impression of a memory leak.

```ruby
10.times do
  5000.times do
    Struct.new("A")
    Struct.send(:remove_const, :A)
  end

  GC.start
  puts `ps -o rss= -p #{$$}`.to_i
end
```

```
27868
35324
43400
51472
58676
66144
73764
81196
88512
95752
```

Is there another location where the struct gets set that I need to clear up for the GC free the memory?

Happens in 3.2.2, 3.2.3, 3.3.0, 3.3-head, ruby-head.



-- 
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