I can now reprocuce corrupt sessions. The trick is to debug 
DFSession>>numberOfMethodCalls:
1. start new session
2. debug "DFSession uniqueInstance printString"
3. step into #numberOfMehthodCalls
4. proceed
5. stop the session
5. right click on the new session in the session browser and click "Export 
session"
6. boom!

The reason is of course, that now the compiled method of #numberOfMethodCalls 
is referenced by the session and will be serialized by Fuel and when Fuel gets 
to the corrupt BlockClosure, serialization fails.

So the real question still is: how did that BlockClosure obtain a wrong start 
PC? What I find particularly interesting, is that even changing the method does 
not fix the BlockClosure. I added the line "Transcript show: 'foo'." before the 
block (so the block should get a new start PC). Then running the procedure 
detailed above still produced an open debugger.
To illustrate that the block did indeed not get fixed I ran "BlockClosure 
allInstances select: [ :e | e startpc = 59 ]", with 59 being the new startPC 
("55 <8F 01 00 03> closureNumCopied: 0 numArgs: 1 bytes 59 to 61"). The result 
does not include the block.


Any ideas?

Max

On 24.05.2013, at 08:10, roberto.mine...@usi.ch wrote:

> Hi,
> 
> Thanks all of you for interest ;)
> 
> On May 24, 2013, at 7:15 AM, Max Leske <maxle...@gmail.com>
> wrote:
> 
>> I played around with reverting the method and serializing but that doesn't 
>> change anything (the existing BlockClosure is obviously not modified).
>> Then I thought that maybe the method was changed during a running DFSession 
>> but still couldn't reproduce.
> 
> Me neither!!
> 
>> 
>> @Roberto
>> Can you tell us anything about what you did befor / during / after running 
>> your session?
> 
> Nope. Unfortunately I've a couple of "broken sessions" I cannot serialize 
> because of that bug.. But all of them refers sooner or later to the 
> DFSession>>#numberOfMethodCalls method. Dunno why.
> 
>> @Roberto
>> Is it possible to reproduce the stack with a new session? Or did this only 
>> happen once?
> 
> I have no clue how to reproduce, but it did not happen only once. As I said, 
> there are 3/4 sessions I couldn't export due to this SubscriptOutOfBounds.
> 
> Cheers,
> Roby
> 
> 
>> 
>> 
>> On 24.05.2013, at 06:44, Max Leske <maxle...@gmail.com> wrote:
>> 
>>> 
>>> On 23.05.2013, at 22:58, Camille Teruel <camille.ter...@gmail.com> wrote:
>>> 
>>>> Hi,
>>>> 
>>>> This is indeed strange, the BlockClosure has an incorrect startpc (31 
>>>> instead of 43). You can fix it with: 
>>>> theBlock instVar: 2 put: 43. 
>>>> The wrong startpc corresponds to the beginning of the block in the 
>>>> previous version of the method (DFSession>>#numberOfMethodCalls), but I 
>>>> don't know why.
>>> 
>>> Would it help to recompile the method?
>>> 
>>>> I don't know fuel enough but could it be because the method of the block 
>>>> changed between serialization and materialization?
>>> 
>>> No, there was never a materialization of that session.
>>> 
>>>> 
>>>> Camille 
>>>> 
>>>> On 23 mai 2013, at 21:02, Max Leske wrote:
>>>> 
>>>>> Hi Marcus
>>>>> 
>>>>> Roberto sent this mail to the Fuel-dev list. When we looked at the 
>>>>> problem we noticed that serialization fails because of a corrupt 
>>>>> BlockClosure. Since that's not really our territorry Mariano suggested to 
>>>>> forward this to you.
>>>>> 
>>>>> The image with the corrupt BlockClosure is available here: 
>>>>> https://dl.dropboxusercontent.com/u/6281855/DFlow-SubscriptOutOfBounds.zip.
>>>>> To see the stack, right click on the only entry in the right window and 
>>>>> click "export session". You'll find the corrupt BlockClosure at 
>>>>> BlockClosure>>fuelAccept:
>>>>> 
>>>>> @Roberto
>>>>> Is it possible to reproduce the stack with a new session? Or did this 
>>>>> only happen once?
>>>>> 
>>>>> 
>>>>> Cheers,
>>>>> Max
>>>>> 
>>>>> 
>>>>> Begin forwarded message:
>>>>> 
>>>>>> From: Mariano Martinez Peck <marianop...@gmail.com>
>>>>>> Subject: Re: [Pharo-fuel] [Fuel] SubscriptOutOfBounds: 27
>>>>>> Date: 23. Mai 2013 14:23:45 MESZ
>>>>>> To: The Fuel Project <pharo-f...@lists.gforge.inria.fr>
>>>>>> Reply-To: The Fuel Project <pharo-f...@lists.gforge.inria.fr>
>>>>>> 
>>>>>> Indeed, it would be nice if you can known which CompiledMethod and 
>>>>>> blockclosure are having the problem. Not only the source code but the 
>>>>>> real bytecodes.
>>>>>> Also, can you isolate and just try to serialize them alone and reproduce 
>>>>>> the problem? In other words, a reproducible test case? :)
>>>>>> Thanks!
>>>>>> 
>>>>>> 
>>>>>> On Thu, May 23, 2013 at 8:41 AM, Max Leske <maxle...@gmail.com> wrote:
>>>>>> What's the compiled method? Is it a special one? Which selector in which 
>>>>>> class?
>>>>>> 
>>>>>> Max
>>>>>> 
>>>>>> On 23.05.2013, at 12:45, "roberto.mine...@usi.ch" 
>>>>>> <roberto.mine...@usi.ch> wrote:
>>>>>> 
>>>>>>> Hi,
>>>>>>> 
>>>>>>> While using Fuel in a 2.0 image to serialize some objects (including 
>>>>>>> CompiledMethods) I'm getting this error: SubscriptOutOfBounds: 27.
>>>>>>> 
>>>>>>> I spent hours in the debugger before writing this email, but I'm not 
>>>>>>> able to figure out why this is happening. I attach the full stack of 
>>>>>>> the error (STACK#1).
>>>>>>> 
>>>>>>> I understood that it has something to do with a particular 
>>>>>>> CompiledMethod in my image and/or a BlockClosure which for some reason 
>>>>>>> cannot be printed (i.e., the printString returns <error in printString: 
>>>>>>> evaluate "self printString" to debug>) and when I try to printString to 
>>>>>>> debug I got the STACK#2 which in turn does not bring me to any possible 
>>>>>>> solution.
>>>>>>> 
>>>>>>> Hope some of you will have an intuition on that or at least tell me 
>>>>>>> where to look or how to script a possible workaround.
>>>>>>> 
>>>>>>> Thanks in advance,
>>>>>>> Roby
>>>>>>> 
>>>>>>> ############################################################################################
>>>>>>> ######################################### STACK#1 
>>>>>>> ###########################################
>>>>>>> ###########################################################################################
>>>>>>> CompiledMethod(Object)>>errorSubscriptBounds:
>>>>>>> CompiledMethod(Object)>>at:
>>>>>>> InstructionStream>>interpretNextInstructionFor:
>>>>>>> CompiledMethod>>abstractBytecodeMessageAt: in Block: 
>>>>>>> [(InstructionStream new method: self pc: pc)...
>>>>>>> BlockClosure>>on:do:
>>>>>>> CompiledMethod>>abstractBytecodeMessageAt:
>>>>>>> BlockClosure>>blockCreationBytecodeMessage
>>>>>>> BlockClosure>>endPC
>>>>>>> BlockClosure>>abstractBytecodeMessagesDo:
>>>>>>> BlockClosure>>isClean
>>>>>>> BlockClosure>>shouldBeSubstitutedByCleanCopy
>>>>>>> BlockClosure>>fuelAccept:
>>>>>>> FLFullGeneralMapper(FLLightGeneralMapper)>>mapAndTrace:
>>>>>>> FLFullGlobalMapper>>mapAndTrace: in Block: [(anObject class == 
>>>>>>> CompiledMethod...
>>>>>>> FLLargeIdentityDictionary>>at:ifAbsent:
>>>>>>> FLFullGlobalMapper>>mapAndTrace:
>>>>>>> FLPluggableSubstitutionMapper>>mapAndTrace:
>>>>>>> FLPluggableSubstitutionMapper>>mapAndTrace:
>>>>>>> FLAnalysis>>mapAndTrace:
>>>>>>> FLAnalysis>>run
>>>>>>> FLAnalyzer>>setDefaultAnalysis in Block: [:anObject | (FLAnalysis...
>>>>>>> FLAnalyzer>>analysisFor:
>>>>>>> FLSerialization>>analysisStep
>>>>>>> FLSerialization>>run
>>>>>>> DFSerializer(FLSerializer)>>setDefaultSerialization in Block: 
>>>>>>> [:anObject :anEncoder | (FLSerialization...
>>>>>>> DFSerializer(FLSerializer)>>serialize:on: in Block: [:anEncoder | ...
>>>>>>> FLEncoder class>>on:globalEnvironment:do: in Block: [aBlock value: 
>>>>>>> anEncoder]
>>>>>>> BlockClosure>>ensure:
>>>>>>> FLEncoder class>>on:globalEnvironment:do:
>>>>>>> DFSerializer(FLSerializer)>>serialize:on:
>>>>>>> 
>>>>>>> 
>>>>>>> ############################################################################################
>>>>>>> ######################################### STACK#2 
>>>>>>> ###########################################
>>>>>>> ############################################################################################
>>>>>>> Decompiler(Object)>>error:
>>>>>>> Decompiler>>decompileBlock:
>>>>>>> BlockClosure>>decompile
>>>>>>> BlockClosure>>printOn:
>>>>>>> BlockClosure(Object)>>printStringLimitedTo: in Block: [:s | self 
>>>>>>> printOn: s]
>>>>>>> String class(SequenceableCollection class)>>streamContents:limitedTo:
>>>>>>> BlockClosure(Object)>>printStringLimitedTo:
>>>>>>> BlockClosure(Object)>>printString
>>>>>>> BlockClosure>>DoIt
>>>>>>> Compiler>>evaluate:in:to:notifying:ifFail:logged:
>>>>>>> SmalltalkEditor>>evaluateSelectionAndDo: in Block: [rcvr class 
>>>>>>> evaluatorClass new...
>>>>>>> BlockClosure>>on:do:
>>>>>>> SmalltalkEditor>>evaluateSelectionAndDo:
>>>>>>> SmalltalkEditor>>evaluateSelection
>>>>>>> PluggableTextMorph>>doIt in Block: [textMorph editor evaluateSelection]
>>>>>>> PluggableTextMorph>>handleEdit: in Block: [result := editBlock value]
>>>>>>> TextMorphForEditView(TextMorph)>>handleEdit:
>>>>>>> PluggableTextMorph>>handleEdit:
>>>>>>> PluggableTextMorph>>doIt
>>>>>>> SmalltalkEditor class>>buildSmalltalkEditorKeymappingsOn: in Block: 
>>>>>>> [:morph | morph doIt]
>>>>>>> BlockClosure>>cull:
>>>>>>> BlockClosure>>cull:cull:
>>>>>>> BlockClosure>>cull:cull:cull:
>>>>>>> KMCategoryTarget>>completeMatch:buffer:
>>>>>>> KMKeymap>>notifyCompleteMatchTo:buffer: in Block: [:l | l 
>>>>>>> completeMatch: self buffer: aBuffer]
>>>>>>> Array(SequenceableCollection)>>do:
>>>>>>> KMKeymap>>notifyCompleteMatchTo:buffer:
>>>>>>> KMKeymap>>onMatchWith:notify:andDo:
>>>>>>> KMCategory>>onMatchWith:notify:andDo: in Block: [:entry | entry...
>>>>>>> Set>>do:
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> _______________________________________________
>>>>>>> Pharo-fuel mailing list
>>>>>>> pharo-f...@lists.gforge.inria.fr
>>>>>>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-fuel
>>>>>> 
>>>>>> _______________________________________________
>>>>>> Pharo-fuel mailing list
>>>>>> pharo-f...@lists.gforge.inria.fr
>>>>>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-fuel
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> -- 
>>>>>> Mariano
>>>>>> http://marianopeck.wordpress.com
>>>>>> _______________________________________________
>>>>>> Pharo-fuel mailing list
>>>>>> pharo-f...@lists.gforge.inria.fr
>>>>>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-fuel
>>>>> 
>>>> 
>>> 
>> 
>> _______________________________________________
>> Pharo-fuel mailing list
>> pharo-f...@lists.gforge.inria.fr
>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-fuel
> 
> 
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