[ruby-dev:52072] [Ruby master Bug#20311] Struct.new("A") memory leak?

["byroot (Jean Boussier) via ruby-dev" <ruby-dev@ml.ruby-lang.org>]

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


> rb_const_remove needs to take care of it when the removed constant is a class or module?

The problem is that it's a set:

```c
st_insert(vm->defined_module_hash, (st_data_t)module, (st_data_t)module);
```

So if a module is added twice, you need to remove it from the set if it's removed twice... I'll see if I can do that.

But I also wonder why we have this root in the first place, I'd think these get marked from being constants in `::Object`.

----------------------------------------
Bug #20311: Struct.new("A") memory leak?
https://bugs.ruby-lang.org/issues/20311#change-107073

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

```
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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