https://github.com/ruby/stringio/commit/cf58a203eb

same bug as: https://github.com/jruby/jruby/issues/9035

https://github.com/ruby/stringio/commit/65b144b175

(https://github.com/ruby/stringio/pull/139)

https://github.com/ruby/stringio/commit/0edc8e22da

https://github.com/ruby/stringio/commit/29b9133332

https://github.com/ruby/stringio/commit/113dd5a55e

on null device
(https://github.com/ruby/stringio/pull/137)

Fixes segmentation fault when calling `seek` with `SEEK_END` on null
device StringIO created by
  `StringIO.new(nil)`.

```bash
ruby -e "require 'stringio'; StringIO.new(nil).seek(0, IO::SEEK_END)"
```

I tested with below versions.

```bash
[koh@Kohs-MacBook-Pro] ~
% ruby -v;gem info stringio;sw_vers
ruby 3.4.5 (2025-07-16 revision https://github.com/ruby/stringio/commit/20cda200d3) +PRISM [arm64-darwin24]

*** LOCAL GEMS ***

stringio (3.1.2)
    Authors: Nobu Nakada, Charles Oliver Nutter
    Homepage: https://github.com/ruby/stringio
    Licenses: Ruby, BSD-2-Clause
    Installed at (default): /Users/koh/.local/share/mise/installs/ruby/3.4.5/lib/ruby/gems/3.4.0

    Pseudo IO on String
ProductName:            macOS
ProductVersion:         15.5
BuildVersion:           24F74
[koh@Kohs-MacBook-Pro] ~
%
```

https://github.com/ruby/stringio/commit/9399747bf9

(https://github.com/ruby/stringio/pull/134)

from https://bugs.ruby-lang.org/issues/21262

We need to alias `Ractor#value` to `Ractor#take` for old versions of
Ruby.

---------

https://github.com/ruby/stringio/commit/9954dabd80

Co-authored-by: Koichi Sasada <ko1@atdot.net>
Co-authored-by: Sutou Kouhei <kou@clear-code.com>

* Added `Ractor::Port`
  * `Ractor::Port#receive` (support multi-threads)
  * `Rcator::Port#close`
  * `Ractor::Port#closed?`
* Added some methods
  * `Ractor#join`
  * `Ractor#value`
  * `Ractor#monitor`
  * `Ractor#unmonitor`
* Removed some methods
  * `Ractor#take`
  * `Ractor.yield`
* Change the spec
  * `Racotr.select`

You can wait for multiple sequences of messages with `Ractor::Port`.

```ruby
ports = 3.times.map{ Ractor::Port.new }
ports.map.with_index do |port, ri|
  Ractor.new port,ri do |port, ri|
    3.times{|i| port << "r#{ri}-#{i}"}
  end
end

p ports.each{|port| pp 3.times.map{port.receive}}

```

In this example, we use 3 ports, and 3 Ractors send messages to them respectively.
We can receive a series of messages from each port.

You can use `Ractor#value` to get the last value of a Ractor's block:

```ruby
result = Ractor.new do
  heavy_task()
end.value
```

You can wait for the termination of a Ractor with `Ractor#join` like this:

```ruby
Ractor.new do
  some_task()
end.join
```

`#value` and `#join` are similar to `Thread#value` and `Thread#join`.

To implement `#join`, `Ractor#monitor` (and `Ractor#unmonitor`) is introduced.

This commit changes `Ractor.select()` method.
It now only accepts ports or Ractors, and returns when a port receives a message or a Ractor terminates.

We removes `Ractor.yield` and `Ractor#take` because:
* `Ractor::Port` supports most of similar use cases in a simpler manner.
* Removing them significantly simplifies the code.

We also change the internal thread scheduler code (thread_pthread.c):
* During barrier synchronization, we keep the `ractor_sched` lock to avoid deadlocks.
  This lock is released by `rb_ractor_sched_barrier_end()`
  which is called at the end of operations that require the barrier.
* fix potential deadlock issues by checking interrupts just before setting UBF.

https://bugs.ruby-lang.org/issues/21262

StringIO does not warn for unchilled unfrozen string or for frozen
string, so it should not warn for chilled string.

https://github.com/ruby/stringio/commit/4ac33b8c70

https://github.com/ruby/stringio/commit/eb4ee49218