Fuel FLMethodChanged error

I'm trying to serialize and materialize some domain objects. If I run this:


FLSerializer serialize: users toFileNamed: 'users.fuel'.


The file users.fuel is created.

If in the same workspace in the same Pharo 1.3 image on Cog 2550 / Linux 64 bit I subsequently run:

FLMaterializer materialzeFromFileNamed: 'users.fuel'

I get an FLMethodChanged error.

If I just serialize and materialize strings, numbers, and DateAndTime objects to files everything works fine and all 248 Fuel tests pass no problem.
 

The incoming method it has a problem with is an #initialize method.

The serializeHash is 15407 and the result of 'method bytecodesHash' is 30998.

What should I check to diagnose/fix this problem?

Thanks

The problem was that in one of the inst vars of my class that had the error I was in some instances storing a Dictionary and other instances storing a SortedCollection with a custom sortBlock.  They should have all been dictionaries but some instances had not been migrated to dictionaries. Once I fixed that the problem went away.

This bit in a workspace also raises an error. I'm not sure why it does and I don't know why you'd ever do it in practice:

|coll|
coll:=OrderedCollection new.
(Interval from: 1 to: 100) do: [:each|
       coll add:( each \\ 2 = 0
               ifTrue: [SortedCollection sortBlock:[:a :c | a name < c name] ]
               ifFalse:[Dictionary new] ) ].

FLSerializer serialize: coll toFileNamed: 'collection.fuel'.

FLMaterializer materializeFromFileNamed: 'collection.fuel'

On 06/07/2012 01:18 PM, Mariano Martinez Peck wrote:

On Thu, Jun 7, 2012 at 10:12 PM, Paul DeBruicker <[hidden email]

<mailto:[hidden email]>> wrote:

   I'm trying to serialize and materialize some domain objects. If I
   run this:


   FLSerializer serialize: users toFileNamed: 'users.fuel'.


   The file users.fuel is created.

   If in the same workspace in the same Pharo 1.3 image on Cog 2550 /
   Linux 64 bit I subsequently run:

   FLMaterializer materialzeFromFileNamed: 'users.fuel'

   I get an FLMethodChanged error.


that looks weird, because you are materializng in the SAME image ...


   If I just serialize and materialize strings, numbers, and
   DateAndTime objects to files everything works fine and all 248 Fuel
   tests pass no problem.

   The incoming method it has a problem with is an #initialize method.


which class is the one that contains that #initialize?
do you have an #initialize in your image that uses pragmas?

   The serializeHash is 15407 and the result of 'method bytecodesHash'
   is 30998.


can you try closing all opened ssytem browsers (nautilus windows or
wharever)?


   What should I check to diagnose/fix this problem?


is your data private or you can provide an image with "users" so that we
can test?

   Thanks




--
Mariano
http://marianopeck.wordpress.com

On 06/07/2012 02:25 PM, Mariano Martinez Peck wrote:

| serializer |
serializer := FLSerializer newFull.
serializer serialize: xxx on: aStream.

and tell me if that also work?

After loading FuelMetaLevel as Martin suggested the above code works to serialize and materialize the problematic domain objects just fine.

After loading FuelMetaLevel as Martin suggested the above code works to serialize and materialize the problematic domain objects just fine.

Ok, just to clarify: when you install the package Fuel only, and in your graph you have entities like classes or methods, they will be considered "global", that is, we just store the class name and selector and during materialization we search it in the Smalltalk globals. If the class/method is not present, we throw an error. Now...closures are more complicated because you can even EVALUATE them. If the method surrounding the closure has changed in the image you are materializing, evaluating the closure (depending on the change in the method) can even crash your VM. Because of that, when serializing methods "as globals" we also store a chemsum and we compare during materialization to see that it hasn't change it. If changed, we throw the FLMethodChanged.
With the package FuelMetalevel, and by using #newFull the serializer will consider the method as "full" so it will be fully serialized, and therefore you don't have the problem of the checksum.

Anyway, you found a bug because you should not be needing FuelMetalevel since you are serializing and materializing in the same image.

 FLSerializer newFull serialize: anObject toFileNamed: 'example'.

We will investigate it.

Thanks

 

--
Mariano
http://marianopeck.wordpress.com