From: "nagachika (Tomoyuki Chikanaga) via ruby-core" <ruby-core@...>
Date: 2024-01-19T08:14:42+00:00
Subject: [ruby-core:116316] [Ruby master Bug#20150] Memory leak in grapheme clusters

Issue #20150 has been updated by nagachika (Tomoyuki Chikanaga).


Hello, Martin-sensei.

In my understandings, there's no explicit rule regarding the order of backporting to each stable branch.
In this case, I backported the changeset to the 3.2 branch ahead of the 3.3 branch because I hoped to include some obvious bug-fixes in ruby-3.2.3 released yesterday. I also think these fixes should be backported to 3.3 branch before release of ruby-3.3.1, but it's up to naruse-san, the current 3.3 branch maintainer.

Best Regards,

----------------------------------------
Bug #20150: Memory leak in grapheme clusters
https://bugs.ruby-lang.org/issues/20150#change-106342

* Author: peterzhu2118 (Peter Zhu)
* Status: Closed
* Priority: Normal
* Backport: 3.0: UNKNOWN, 3.1: REQUIRED, 3.2: DONE, 3.3: REQUIRED
----------------------------------------
GitHub PR: https://github.com/ruby/ruby/pull/9414

String#grapheme_cluters and String#each_grapheme_cluster leaks memory because if the string is not UTF-8, then the created regex will not be freed.

For example:

```ruby
str = "hello world".encode(Encoding::UTF_32LE)

10.times do
  1_000.times do
    str.grapheme_clusters
  end

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

Before:

```
26000
42256
59008
75792
92528
109232
125936
142672
159392
176160
```

After:

```
9264
9504
9808
10000
10128
10224
10352
10544
10704
10896
```



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