ruby​​とjrubyでbegin-next-endの動作が異なるのはなぜですか？

Question

は（彼らは同じですが、結果は異なります）次のシナリオの比較：

まず、私はルビーでそれをやるのJRuby上（cruby）

~> irb 
irb(main):001:0> begin 
irb(main):002:1* begin 
irb(main):003:2* puts 1 
irb(main):004:2> next 
irb(main):005:2> end 
irb(main):006:1> puts 2 
irb(main):007:1> end 
SyntaxError: (irb):4: Can't escape from eval with next 

今同じこと：

~> jirb 
irb(main):001:0> begin 
irb(main):002:1* begin 
irb(main):003:2* puts 1 
irb(main):004:2> next 
irb(main):005:2> end 
irb(main):006:1> puts 2 
irb(main):007:1> end 
1 
=> nil 

これはcrubyのようにjrubyで失敗しないのはなぜですか？これは厄介なバグですか？

Answer 1

私はこれをBug #13064として提出しました。

私はYARVのバージョンの様々なだけでなく、JRubyの、MRuby、およびRubiniusの最新バージョンでは、あなたのコードをテストした：

• YARV 2.2.0（MacOSので出荷ビルド）

  を

  # ruby -v -W -e 'begin; begin puts 1; next end; puts 2 end' 
  ruby 2.0.0p648 (2015-12-16 revision 53162) [universal.x86_64-darwin16] 
  -e:1: warning: statement not reached 
  -e:1: Invalid next 
  -e: compile error (SyntaxError) 
  
  # irb -f -d -w -W 
  irb(main):001:0> p RUBY_VERSION 
  "2.0.0" 
  => "2.0.0" 
  irb(main):002:0> p RUBY_ENGINE 
  "ruby" 
  => "ruby" 
  irb(main):003:0> 
  irb(main):004:0* begin 
  irb(main):005:1* begin 
  irb(main):006:2*  puts 1 
  irb(main):007:2>  next 
  irb(main):008:2> end 
  irb(main):009:1> puts 2 
  irb(main):010:1> end 
  (irb):9: warning: statement not reached 
  Exception `SyntaxError' at /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/workspace.rb:86 - (irb):7: Can't escape from eval with next 
  Exception `SyntaxError' at /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/irb/workspace.rb:86 - (irb):7: Can't escape from eval with next 
  SyntaxError: (irb):7: Can't escape from eval with next 
      from (irb) 
  irb(main):011:0> 
  irb(main):012:0* exit 
  

• YARV 2.3.1（現時点でのJRubyと互換性があると主張バージョン）

  # ruby -v -W -e 'begin; begin puts 1; next end; puts 2 end' 
  ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin16] 
  -e:1: warning: statement not reached 
  -e: -e:1: Invalid next (SyntaxError) 
  
  # irb -f -d -w -W 
  irb(main):001:0> p RUBY_VERSION 
  "2.3.1" 
  => "2.3.1" 
  irb(main):002:0> p RUBY_ENGINE 
  "ruby" 
  => "ruby" 
  irb(main):003:0> 
  irb(main):004:0* begin 
  irb(main):005:1* begin 
  irb(main):006:2*  puts 1 
  irb(main):007:2>  next 
  irb(main):008:2> end 
  irb(main):009:1> puts 2 
  irb(main):010:1> end 
  (irb):9: warning: statement not reached 
  Exception `SyntaxError' at /Users/joerg/.rbenv/versions/2.3.1/lib/ruby/2.3.0/irb/workspace.rb:87 - (irb):7: Can't escape from eval with next 
  Exception `SyntaxError' at /Users/joerg/.rbenv/versions/2.3.1/lib/ruby/2.3.0/irb/workspace.rb:87 - (irb):7: Can't escape from eval with next 
  Exception `SyntaxError' at /Users/joerg/.rbenv/versions/2.3.1/lib/ruby/2.3.0/irb/workspace.rb:87 - (irb):7: Can't escape from eval with next 
  SyntaxError: (irb):7: Can't escape from eval with next 
      from (irb) 
  irb(main):011:0> 
  irb(main):012:0* exit 
  

• YARV 2.3.3

  # ruby -v -W -e 'begin; begin puts 1; next end; puts 2 end' 
  ruby 2.3.3p222 (2016-11-21 revision 56859) [x86_64-darwin16] 
  -e:1: warning: statement not reached 
  -e: -e:1: Invalid next (SyntaxError) 
  
  # irb -f -d -w -W 
  irb(main):001:0> p RUBY_VERSION 
  "2.3.3" 
  => "2.3.3" 
  irb(main):002:0> p RUBY_ENGINE 
  "ruby" 
  => "ruby" 
  irb(main):003:0> 
  irb(main):004:0* begin 
  irb(main):005:1* begin 
  irb(main):006:2*  puts 1 
  irb(main):007:2>  next 
  irb(main):008:2> end 
  irb(main):009:1> puts 2 
  irb(main):010:1> end 
  (irb):9: warning: statement not reached 
  Exception `SyntaxError' at /Users/joerg/.rbenv/versions/2.3.3/lib/ruby/2.3.0/irb/workspace.rb:87 - (irb):7: Can't escape from eval with next 
  Exception `SyntaxError' at /Users/joerg/.rbenv/versions/2.3.3/lib/ruby/2.3.0/irb/workspace.rb:87 - (irb):7: Can't escape from eval with next 
  Exception `SyntaxError' at /Users/joerg/.rbenv/versions/2.3.3/lib/ruby/2.3.0/irb/workspace.rb:87 - (irb):7: Can't escape from eval with next 
  SyntaxError: (irb):7: Can't escape from eval with next 
      from (irb) 
  irb(main):011:0> 
  irb(main):012:0* exit 
  

• YARV 2.4.0-preview3：

  # ruby -v -W -e 'begin; begin puts 1; next end; puts 2 end' 
  ruby 2.4.0preview3 (2016-11-07 trunk 56661) [x86_64-darwin16] 
  -e:1: warning: statement not reached 
  -e: -e:1: Invalid next (SyntaxError) 
  
  # irb -f -d -w -W 
  irb(main):001:0> p RUBY_VERSION 
  "2.4.0" 
  => "2.4.0" 
  irb(main):002:0> p RUBY_ENGINE 
  "ruby" 
  => "ruby" 
  irb(main):003:0> 
  irb(main):004:0* begin 
  irb(main):005:1* begin 
  irb(main):006:2*  puts 1 
  irb(main):007:2>  next 
  irb(main):008:2> end 
  irb(main):009:1> puts 2 
  irb(main):010:1> end 
  (irb):9: warning: statement not reached 
  Exception `SyntaxError' at /Users/joerg/.rbenv/versions/2.4.0-preview3/lib/ruby/2.4.0/irb/workspace.rb:87 - (irb):7: Can't escape from eval with next 
  SyntaxError: (irb):7: Can't escape from eval with next 
      from (irb) 
  irb(main):011:0> 
  irb(main):012:0* exit 
  

• YARV 2.4.0-DEV（昨日のような現在のSVNトランク）：

  # ruby -v -W -e 'begin; begin puts 1; next end; puts 2 end' 
  ruby 2.4.0dev (2016-12-22 trunk 57151) [x86_64-darwin16] 
  -e:1: warning: statement not reached 
  -e: -e:1: Invalid next (SyntaxError) 
  
  # irb -f -d -w -W 
  irb(main):001:0> p RUBY_VERSION 
  "2.4.0" 
  => "2.4.0" 
  irb(main):002:0> p RUBY_ENGINE 
  "ruby" 
  => "ruby" 
  irb(main):003:0> 
  irb(main):004:0* begin 
  irb(main):005:1* begin 
  irb(main):006:2*  puts 1 
  irb(main):007:2>  next 
  irb(main):008:2> end 
  irb(main):009:1> puts 2 
  irb(main):010:1> end 
  (irb):9: warning: statement not reached 
  Exception `SyntaxError' at /Users/joerg/.rbenv/versions/2.4.0-dev/lib/ruby/2.4.0/irb/workspace.rb:87 - (irb):7: Can't escape from eval with next 
  SyntaxError: (irb):7: Can't escape from eval with next 
      from (irb) 
  irb(main):011:0> 
  irb(main):012:0* exit 
  

• ルビニウス3.69

  # rbx -v -W -e 'begin; begin puts 1; next end; puts 2 end' 
  rubinius 3.69 (2.3.1 a57071c6 2016-11-17 3.8.1) [x86_64-darwin15.6.0] 
  1 
         main # Rubinius::Loader at core/loader.rb:860 
         evals # Rubinius::Loader at core/loader.rb:646 
         eval # Kernel(Rubinius::Loader) at core/kernel.rb:1130 
      call_on_instance # Rubinius::BlockEnvironment at core/block_environment.rb:147 
      { } in __script__ # Object at -e:1 
        jump_error . Rubinius at core/rubinius.rb:279 
  
  invalid context for 'next' (LocalJumpError) 
  
  An exception occurred evaluating command line code 
  
  # irb 
  irb(main):001:0> p RUBY_VERSION 
  "2.3.1" 
  => "2.3.1" 
  irb(main):002:0> p RUBY_ENGINE 
  "rbx" 
  => "rbx" 
  irb(main):003:0> 
  irb(main):004:0* begin 
  irb(main):005:1* begin 
  irb(main):006:2*  puts 1 
  irb(main):007:2>  next 
  irb(main):008:2> end 
  irb(main):009:1> puts 2 
  irb(main):010:1> end 
  1 
  LocalJumpError: invalid context for 'next' 
      from core/rubinius.rb:279:in `jump_error' 
      from (irb):7 
      from core/block_environment.rb:147:in `call_on_instance' 
      from core/kernel.rb:1130:in `eval' 
      from core/kernel.rb:585:in `loop' 
      from core/proc.rb:20:in `call' 
      from core/kernel.rb:1067:in `catch' 
      from core/throw_catch.rb:8:in `register' 
      from core/kernel.rb:1066:in `catch' 
      from core/proc.rb:20:in `call' 
      from core/kernel.rb:1067:in `catch' 
      from core/throw_catch.rb:8:in `register' 
      from core/kernel.rb:1066:in `catch' 
      from core/code_loader.rb:505:in `load_script' 
      from core/code_loader.rb:590:in `load_script' 
      from core/loader.rb:679:in `script' 
      from core/loader.rb:861:in `main'irb(main):011:0> 
  irb(main):012:0* exit 
  

• JRubyの9.1.6.0（最新版）

  # jruby -v -W -e 'begin; begin puts 1; next end; puts 2 end' 
  jruby 9.1.6.0 (2.3.1) 2016-11-09 0150a76 Java HotSpot(TM) 64-Bit Server VM 25.102-b14 on 1.8.0_102-b14 +jit [darwin-x86_64] 
  1 
  LocalJumpError: unexpected next 
      <main> at -e:1 
  
  # irb -f -d -w -W 
  irb(main):001:0> p RUBY_VERSION 
  "2.3.1" 
  => "2.3.1" 
  irb(main):002:0> p RUBY_ENGINE 
  "jruby" 
  => "jruby" 
  irb(main):003:0> 
  irb(main):004:0* begin 
  irb(main):005:1* begin 
  irb(main):006:2*  puts 1 
  irb(main):007:2>  next 
  irb(main):008:2> end 
  irb(main):009:1> puts 2 
  irb(main):010:1> end 
  1 
  => nil 
  irb(main):011:0> 
  irb(main):012:0* exit 
  

• MRuby 1.2.0（自分自身をマッツによって書かれた最低限のISO準拠したRubyの実装）ほとんどは何

  # mruby -v -e 'begin; begin puts 1; next end; puts 2 end' 
  mruby 1.2.0 (2015-11-17) 
  00001 NODE_SCOPE: 
  00001 NODE_BEGIN: 
  00001  NODE_BEGIN: 
  00001  NODE_BEGIN: 
  00001   NODE_CALL: 
  00001   NODE_SELF 
  00001   method='puts' (383) 
  00001   args: 
  00001    NODE_INT 1 base 10 
  00001   NODE_NEXT: 
  00001  NODE_CALL: 
  00001   NODE_SELF 
  00001   method='puts' (383) 
  00001   args: 
  00001   NODE_INT 2 base 10 
  irep 0x7fe0e3c1b630 nregs=4 nlocals=1 pools=1 syms=1 reps=0 
  file: -e 
      1 000 OP_LOADSELF R1  
      1 001 OP_LOADI R2 1 
      1 002 OP_SEND R1 :puts 1 
      1 003 OP_ERR "unexpected next" 
      1 004 OP_LOADSELF R1  
      1 005 OP_LOADI R2 2 
      1 006 OP_SEND R1 :puts 1 
      1 007 OP_STOP 
  
  1 
  trace: 
      [0] -e:1 
  LocalJumpError: unexpected next 
  
  # irb -v 
  mruby 1.2.0 (2015-11-17) 
  mirb - Embeddable Interactive Ruby Shell 
  
  > p RUBY_VERSION 
  00001 NODE_SCOPE: 
  00001 NODE_BEGIN: 
  00001  NODE_CALL: 
  00001  NODE_SELF 
  00001  method='p' (384) 
  00001  args: 
  00001   NODE_CONST RUBY_VERSION 
  irep 0x7fceeac05220 nregs=4 nlocals=1 pools=0 syms=2 reps=0 
  file: (mirb) 
      1 000 OP_LOADSELF R1  
      1 001 OP_GETCONST R2 :RUBY_VERSION 
      1 002 OP_SEND R1 :p 1 
      1 003 OP_STOP 
  
  "1.9" 
  => "1.9" 
  > p RUBY_ENGINE 
  00002 NODE_SCOPE: 
  00002 NODE_BEGIN: 
  00002  NODE_CALL: 
  00002  NODE_SELF 
  00002  method='p' (384) 
  00002  args: 
  00002   NODE_CONST RUBY_ENGINE 
  irep 0x7fceeae05cf0 nregs=4 nlocals=1 pools=0 syms=2 reps=0 
  file: (mirb) 
      2 000 OP_LOADSELF R1  
      2 001 OP_GETCONST R2 :RUBY_ENGINE 
      2 002 OP_SEND R1 :p 1 
      2 003 OP_STOP 
  
  "mruby" 
  => "mruby" 
  > 
  00004 NODE_SCOPE: 
  00004 NODE_BEGIN: 
  irep 0x7fceeac06a50 nregs=2 nlocals=1 pools=0 syms=0 reps=0 
  file: (mirb) 
      4 000 OP_LOADNIL R1  
      4 001 OP_STOP 
  
  => nil 
  > begin 
  00005 NODE_NIL 
  * begin 
  00007 NODE_NIL 
  *  puts 1 
  00009 NODE_NIL 
  *  next 
  00011 NODE_NIL 
  * end 
  00013 NODE_NIL 
  * puts 2 
  00015 NODE_NIL 
  * end 
  00012 NODE_SCOPE: 
  00012 NODE_BEGIN: 
  00012  NODE_BEGIN: 
  00012  NODE_BEGIN: 
  00012   NODE_CALL: 
  00012   NODE_SELF 
  00012   method='puts' (383) 
  00012   args: 
  00012    NODE_INT 1 base 10 
  00013   NODE_NEXT: 
  00015  NODE_CALL: 
  00015   NODE_SELF 
  00015   method='puts' (383) 
  00015   args: 
  00015   NODE_INT 2 base 10 
  irep 0x7fceeae01130 nregs=4 nlocals=1 pools=1 syms=1 reps=0 
  file: (mirb) 
      12 000 OP_LOADSELF R1  
      12 001 OP_LOADI R2 1 
      12 002 OP_SEND R1 :puts 1 
      13 003 OP_ERR "unexpected next" 
      15 004 OP_LOADSELF R1  
      15 005 OP_LOADI R2 2 
      15 006 OP_SEND R1 :puts 1 
      15 007 OP_STOP 
  
  1 
  LocalJumpError: unexpected next 
  > 
  00012 NODE_SCOPE: 
  00012 NODE_BEGIN: 
  irep 0x7fceeae078f0 nregs=2 nlocals=1 pools=0 syms=0 reps=0 
  file: (mirb) 
      12 000 OP_LOADNIL R1  
      12 001 OP_STOP 
  
  => nil 
  > exit 
  

興味深いことに、MRuby、JRuby、Rubiniusは実際に行動に同意しますが、YARVとは異なります。 YARVか他のすべてが間違っています。しかし、私はどちらかと言うことはできません。

Answer 2

MRIは、Ruby 1.9の時間枠の周りで、LocalJumpErrorを発生させるのではなく、解析時にこれらの不正なジャンプケースの一部を検出し始めました。 JRuby、MRuby、Rubiniusは、ジャンプをそのままにしておき、すぐに構文エラーを出すのではなく、後で失敗する可能性が高いです。

JRubyでバグを報告する価値があるかもしれません。パーザは基本的にMRIのポートですので、同じエラーを発生させることができます。それを除けば、私たちはこの分析をコンパイル時に実行してエラーを発生させることができます。