Ruby 2.5.0为什么在Alpine Linux中提高SystemStackError，即使堆栈级别的深度不太高

Question

这是复制问题的示例代码。

# test.rb
n = 100000
res = {}
1.upto(n).to_a.inject(res) do |r, i|
  r[i] = {}
end
def f(x)
  x.each_value { |v| f(v) }
end
f(res)

使用Docker Hub提供的Docker图像运行此代码。

• Alpine Linux中的Ruby 2.5.0是意外（不太深）
• Alpine Linux中的Ruby 2.4.3是预期
• ruby 2.5.0在debian是预期

是什么有所作为？

补充说明

（对不起，我的英语不好。）

这是一个补充解释。

我知道示例代码原因SystemStackError。我编写了示例代码来导致SystemStackError。

我想知道"级别"差异的原因。

• Alpine Linux中的Ruby 2.5.0->" ... 137级..."
• Alpine Linux中的Ruby 2.4.3 ->" ... 10067级..."
• ruby 2.5.0在debian->" ... 9866级别..."

Ruby 2.5.0 Alpine Linux（Ruby：2.5.0-Alpine3.7）

在这种情况下，堆栈级别为137。

% docker container run -v (pwd):/mnt/my --rm -it ruby:2.5.0-alpine3.7 ruby -v /mnt/my/test.rb
ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-linux-musl]
Traceback (most recent call last):
        149: from /mnt/my/test.rb:11:in `<main>'
        148: from /mnt/my/test.rb:8:in `f'
        147: from /mnt/my/test.rb:8:in `each_value'
        146: from /mnt/my/test.rb:8:in `block in f'
        145: from /mnt/my/test.rb:8:in `f'
        144: from /mnt/my/test.rb:8:in `each_value'
        143: from /mnt/my/test.rb:8:in `block in f'
        142: from /mnt/my/test.rb:8:in `f'
         ... 137 levels...
          4: from /mnt/my/test.rb:8:in `f'
          3: from /mnt/my/test.rb:8:in `each_value'
          2: from /mnt/my/test.rb:8:in `block in f'
          1: from /mnt/my/test.rb:8:in `f'
/mnt/my/test.rb:8:in `each_value': stack level too deep (SystemStackError)

但简单的情况，堆栈级别为13092。

% docker container run --rm -it ruby:2.5.0-alpine3.7 ruby -v -e 'def f; f; end; f'
ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-linux-musl]
Traceback (most recent call last):
        13104: from -e:1:in `<main>'
        13103: from -e:1:in `f'
        13102: from -e:1:in `f'
        13101: from -e:1:in `f'
        13100: from -e:1:in `f'
        13099: from -e:1:in `f'
        13098: from -e:1:in `f'
        13097: from -e:1:in `f'
         ... 13092 levels...
            4: from -e:1:in `f'
            3: from -e:1:in `f'
            2: from -e:1:in `f'
            1: from -e:1:in `f'
-e:1:in `f': stack level too deep (SystemStackError)

Ruby 2.4.3 Alpine Linux（Ruby：2.4.3-Alpine3.7）

在这种情况下，堆栈级别为10067。与上述情况有很大的区别。

% docker container run -v (pwd):/mnt/my --rm -it ruby:2.4.3-alpine3.7 ruby -v /mnt/my/test.rb
ruby 2.4.3p205 (2017-12-14 revision 61247) [x86_64-linux-musl]
/mnt/my/test.rb:8:in `each_value': stack level too deep (SystemStackError)
        from /mnt/my/test.rb:8:in `f'
        from /mnt/my/test.rb:8:in `block in f'
        from /mnt/my/test.rb:8:in `each_value'
        from /mnt/my/test.rb:8:in `f'
        from /mnt/my/test.rb:8:in `block in f'
        from /mnt/my/test.rb:8:in `each_value'
        from /mnt/my/test.rb:8:in `f'
        from /mnt/my/test.rb:8:in `block in f'
         ... 10067 levels...
        from /mnt/my/test.rb:8:in `block in f'
        from /mnt/my/test.rb:8:in `each_value'
        from /mnt/my/test.rb:8:in `f'
        from /mnt/my/test.rb:11:in `<main>'

i显示 diff dockerfile的输出。

--- 2.4/alpine3.7/Dockerfile    2017-12-28 20:34:43.000000000 +0900
+++ 2.5/alpine3.7/Dockerfile    2017-12-28 20:34:43.000000000 +0900
@@ -7,9 +7,9 @@
                echo 'update: --no-document'; 
        } >> /usr/local/etc/gemrc
-ENV RUBY_MAJOR 2.4
-ENV RUBY_VERSION 2.4.3
-ENV RUBY_DOWNLOAD_SHA256 23677d40bf3b7621ba64593c978df40b1e026d8653c74a0599f0ead78ed92b51
+ENV RUBY_MAJOR 2.5
+ENV RUBY_VERSION 2.5.0
+ENV RUBY_DOWNLOAD_SHA256 1da0afed833a0dab94075221a615c14487b05d0c407f991c8080d576d985b49b
 ENV RUBYGEMS_VERSION 2.7.4
 ENV BUNDLER_VERSION 1.16.1

这意味着使用相同的高山Linux。只是红宝石是不同的。

Ruby 2.5.0 Debian（Ruby：2.5.0-stretch）

在这种情况下，堆栈级别为9866。这种情况使用Ruby 2.5.0，但在Debian（不是Alpine）运行。

% docker container run -v (pwd):/mnt/my --rm -it ruby:2.5.0-stretch ruby -v /mnt/my/test.rb
ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-linux]
Traceback (most recent call last):
        9878: from /mnt/my/test.rb:11:in `<main>'
        9877: from /mnt/my/test.rb:8:in `f'
        9876: from /mnt/my/test.rb:8:in `each_value'
        9875: from /mnt/my/test.rb:8:in `block in f'
        9874: from /mnt/my/test.rb:8:in `f'
        9873: from /mnt/my/test.rb:8:in `each_value'
        9872: from /mnt/my/test.rb:8:in `block in f'
        9871: from /mnt/my/test.rb:8:in `f'
         ... 9866 levels...
           4: from /mnt/my/test.rb:8:in `f'
           3: from /mnt/my/test.rb:8:in `each_value'
           2: from /mnt/my/test.rb:8:in `block in f'
           1: from /mnt/my/test.rb:8:in `f'
/mnt/my/test.rb:8:in `each_value': stack level too deep (SystemStackError)

Answer 1

我们在某些边缘情况下也看到了这一点。我们已经确认在所有情况下，OS和Ruby堆栈尺寸都是相同的。（Alpine 2.4.3，Alpine 2.5.0，并在MacOS上本地运行2.5.0）

我们唯一能找到的差异化因素是Alpine 2.5.0图像是用Alpine 3.7构建的，Alpine 3.7用Libressl构建Ruby。2.4.3图像是由Alpine 3.4构建的，该图像仍在使用OpenSSL。我们的本地2.5.0反对OpenSSL构建，并未显示此"短"堆栈长度。