Forum: JRuby JRuby org.yecht.Emitter.scanScalar(Emitter.java:446) error and how to prevent jruby from completely

Hi,

I'm looking for workaround for an interesting problem I have. Or some
explanation why this can happen so I can think about workaround.

For certain data (I'm still unable to figure out what is offending 
part),
calling *YAML.dump* in jruby is crashing jruby process with
the following stack which start with "*
org.yecht.Emitter.scanScalar(Emitter.java:446)*" (full stack is 
attached).
The offending data is just a simple json object - relatively big.

The problem is that I this error crashes the entire process :( - even
putting begin/rescue does not help.

So I have two questions:

   1. Is there some way to protect my jruby process
   from completely crashing?

   2. What could be causing the error like this in *YAML.dump*?
   (Unfortunately, the data which causes this problem is client's data 
so I
   cannot share with it - I'm still trying to figure out what is 
offending
   part).

Thanks,
KB


P.S. Here is the stack trace:



ERROR: 209
----------------
org.yecht.Emitter.scanScalar(Emitter.java:446)
org.yecht.Emitter.emitScalar(Emitter.java:503)
org.yecht.ruby.RubyEmitterHandler.handle(RubyEmitterHandler.java:42)
org.yecht.Emitter.emit(Emitter.java:280)
org.yecht.Emitter.emitItem(Emitter.java:949)
org.yecht.ruby.RubyEmitterHandler.handle(RubyEmitterHandler.java:28)
org.yecht.Emitter.emit(Emitter.java:280)
org.yecht.Emitter.emitItem(Emitter.java:949)
org.yecht.ruby.RubyEmitterHandler.handle(RubyEmitterHandler.java:36)
org.yecht.Emitter.emit(Emitter.java:280)
org.yecht.Emitter.emitItem(Emitter.java:949)
org.yecht.ruby.RubyEmitterHandler.handle(RubyEmitterHandler.java:28)
org.yecht.Emitter.emit(Emitter.java:280)
org.yecht.Emitter.emitItem(Emitter.java:949)
org.yecht.ruby.RubyEmitterHandler.handle(RubyEmitterHandler.java:28)
org.yecht.Emitter.emit(Emitter.java:280)
org.yecht.ruby.YEmitter.emit(YEmitter.java:115)
org.yecht.ruby.YEmitter$s$0$1$emit_DBG.call(YEmitter$s$0$1$emit_DBG.gen:65535)
org.jruby.internal.runtime.methods.DynamicMethod.call(DynamicMethod.java:211)
org.jruby.runtime.callsite.CachingCallSite.callBlock(CachingCallSite.java:176)
org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:182)
org.jruby.ast.CallOneArgBlockPassNode.interpret(CallOneArgBlockPassNode.java:60)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:255)
org.jruby.runtime.callsite.CachingCallSite.callBlock(CachingCallSite.java:210)
org.jruby.runtime.callsite.CachingCallSite.callIter(CachingCallSite.java:221)
org.jruby.ast.CallTwoArgBlockNode.interpret(CallTwoArgBlockNode.java:62)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:190)
org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:167)
org.jruby.ast.CallOneArgNode.interpret(CallOneArgNode.java:57)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:190)
org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:167)
org.jruby.ast.CallOneArgNode.interpret(CallOneArgNode.java:57)
org.jruby.ast.CallTwoArgNode.interpret(CallTwoArgNode.java:59)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.evaluator.ASTInterpreter.INTERPRET_BLOCK(ASTInterpreter.java:111)
org.jruby.runtime.InterpretedBlock.evalBlockBody(InterpretedBlock.java:374)
org.jruby.runtime.InterpretedBlock.yield(InterpretedBlock.java:295)
org.jruby.runtime.InterpretedBlock.yieldSpecific(InterpretedBlock.java:229)
org.jruby.runtime.Block.yieldSpecific(Block.java:99)
org.jruby.ast.ZYieldNode.interpret(ZYieldNode.java:25)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:169)
org.jruby.runtime.callsite.CachingCallSite.callBlock(CachingCallSite.java:142)
org.jruby.runtime.callsite.CachingCallSite.callIter(CachingCallSite.java:153)
org.jruby.ast.FCallNoArgBlockNode.interpret(FCallNoArgBlockNode.java:32)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:233)
org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:201)
org.jruby.ast.CallTwoArgNode.interpret(CallTwoArgNode.java:59)
org.jruby.ast.RescueNode.executeBody(RescueNode.java:216)
org.jruby.ast.RescueNode.interpretWithJavaExceptions(RescueNode.java:120)
org.jruby.ast.RescueNode.interpret(RescueNode.java:110)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.ast.IfNode.interpret(IfNode.java:117)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.ast.IfNode.interpret(IfNode.java:117)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.ast.RescueNode.executeBody(RescueNode.java:216)
org.jruby.ast.RescueNode.interpretWithJavaExceptions(RescueNode.java:120)
org.jruby.ast.RescueNode.interpret(RescueNode.java:110)
org.jruby.ast.BeginNode.interpret(BeginNode.java:83)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:190)
org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:167)
org.jruby.ast.FCallOneArgNode.interpret(FCallOneArgNode.java:36)
org.jruby.ast.LocalAsgnNode.interpret(LocalAsgnNode.java:123)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:120)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:134)
org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:69)
org.jruby.ast.FCallManyArgsNode.interpret(FCallManyArgsNode.java:60)
org.jruby.ast.CallOneArgNode.interpret(CallOneArgNode.java:57)
org.jruby.ast.LocalAsgnNode.interpret(LocalAsgnNode.java:123)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.ast.IfNode.interpret(IfNode.java:117)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.ast.RescueNode.executeBody(RescueNode.java:216)
org.jruby.ast.RescueNode.interpretWithJavaExceptions(RescueNode.java:120)
org.jruby.ast.RescueNode.interpret(RescueNode.java:110)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:233)
org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:201)
org.jruby.ast.FCallTwoArgNode.interpret(FCallTwoArgNode.java:38)
org.jruby.ast.LocalAsgnNode.interpret(LocalAsgnNode.java:123)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.IfNode.interpret(IfNode.java:117)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:233)
org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:332)
org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:203)
org.jruby.ast.CallTwoArgNode.interpret(CallTwoArgNode.java:59)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.evaluator.ASTInterpreter.INTERPRET_BLOCK(ASTInterpreter.java:111)
org.jruby.runtime.InterpretedBlock.evalBlockBody(InterpretedBlock.java:374)
org.jruby.runtime.InterpretedBlock.yield(InterpretedBlock.java:295)
org.jruby.runtime.InterpretedBlock.yieldSpecific(InterpretedBlock.java:229)
org.jruby.runtime.Block.yieldSpecific(Block.java:99)
org.jruby.ast.ZYieldNode.interpret(ZYieldNode.java:25)
org.jruby.ast.LocalAsgnNode.interpret(LocalAsgnNode.java:123)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:212)
org.jruby.runtime.callsite.CachingCallSite.callBlock(CachingCallSite.java:176)
org.jruby.runtime.callsite.CachingCallSite.callIter(CachingCallSite.java:187)
org.jruby.ast.FCallOneArgBlockNode.interpret(FCallOneArgBlockNode.java:34)
org.jruby.ast.LocalAsgnNode.interpret(LocalAsgnNode.java:123)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.ast.IfNode.interpret(IfNode.java:119)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.evaluator.ASTInterpreter.INTERPRET_METHOD(ASTInterpreter.java:74)
org.jruby.internal.runtime.methods.InterpretedMethod.call(InterpretedMethod.java:233)
org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:201)
org.jruby.ast.FCallTwoArgNode.interpret(FCallTwoArgNode.java:38)
org.jruby.ast.DAsgnNode.interpret(DAsgnNode.java:110)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.evaluator.ASTInterpreter.INTERPRET_BLOCK(ASTInterpreter.java:111)
org.jruby.runtime.InterpretedBlock.evalBlockBody(InterpretedBlock.java:374)
org.jruby.runtime.InterpretedBlock.yield(InterpretedBlock.java:295)
org.jruby.runtime.InterpretedBlock.yieldSpecific(InterpretedBlock.java:229)
org.jruby.runtime.Block.yieldSpecific(Block.java:99)
org.jruby.ast.ZYieldNode.interpret(ZYieldNode.java:25)
org.jruby.ast.DAsgnNode.interpret(DAsgnNode.java:110)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.ast.BlockNode.interpret(BlockNode.java:71)
org.jruby.ast.RescueNode.executeBody(RescueNode.java:216)
org.jruby.ast.RescueNode.interpretWithJavaExceptions(RescueNode.java:120)
org.jruby.ast.RescueNode.interpret(RescueNode.java:110)
org.jruby.ast.EnsureNode.interpret(EnsureNode.java:96)
org.jruby.ast.BeginNode.interpret(BeginNode.java:83)
org.jruby.ast.NewlineNode.interpret(NewlineNode.java:104)
org.jruby.evaluator.ASTInterpreter.INTERPRET_BLOCK(ASTInterpreter.java:111)
org.jruby.runtime.InterpretedBlock.evalBlockBody(InterpretedBlock.java:374)
org.jruby.runtime.InterpretedBlock.yield(InterpretedBlock.java:328)
org.jruby.runtime.BlockBody.call(BlockBody.java:73)
org.jruby.runtime.Block.call(Block.java:89)
org.jruby.RubyProc.call(RubyProc.java:270)
org.jruby.RubyProc.call(RubyProc.java:224)
org.jruby.internal.runtime.RubyRunnable.run(RubyRunnable.java:95)
java.lang.Thread.run(Thread.java:722)

Hmm. Yecht. That might be a problem #1. Is it possible to move to Psych 
as the YAML parser instead? I do not believe Yecht[1] is maintained any 
longer.

While it is almost impossible to diagnose this problem remotely, I 
suspect that there is an array element violation on the line indicated. 
If you are not using JRuby 1.7.0[2], I believe you can rescue Java 
exception. You might want to try that.

[1] https://github.com/olabini/yecht
[2] This will be fixed in 1.7.1 
http://jira.codehaus.org/browse/JRUBY-6978

Thanks!

How can I force to use Psych YAML parser for this case? I'm using jruby
1.6.8 and it is somehow calling Yecht when I do "bla".to_yaml
There might some gem which needs Yecht but for particular case it should 
be
ok to use Psych parser.

Any suggestion?

t_7$ jruby -v
jruby 1.6.8 (ruby-1.8.7-p357) (2012-09-18 1772b40) (Java HotSpot(TM) 
64-Bit
Server VM 1.7.0_09) [linux-amd64-java]

Thanks,
KB

Hmm. I might have to take that back. In order to use Psych, your 
application needs to run in the 1.9 mode:

$ jruby -v --1.9 -ryaml -e 'p YAML.parser'
jruby 1.6.8 (ruby-1.9.2-p312) (2012-09-18 1772b40) (Java HotSpot(TM) 
64-Bit Server VM 1.7.0_09) [darwin-x86_64-java]
#<Psych::Parser:0x54f21f54 @handler=#<Psych::TreeBuilder:0x4286ae77 
@root=nil, @last=nil, @stack=[]>>

That looks like a long stack trace.  Hiro, do you think it might be 
something as simple as running out of stack space, and increasing the 
stack size might help?

- Keith

---
Keith R. Bennett
http://about.me/keithrbennett

I tend to think not. If we run out of stack, then we should get an 
Exception indicating that instead.

My guess is that AIOOBE is thrown here: 
https://github.com/olabini/yecht/blob/master/src/m...

This is dependent on input data, and even if we did have data to verify 
it, there is little reason to fix Yecht.