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Bug 358564

Summary:	[Xtend][Memory Leak] Create Extensions - Possibility to clear caches.
Product:	[Modeling] TMF	Reporter:	Christian Dietrich <christian.dietrich.opensource>
Component:	Xtext	Assignee:	Project Inbox <tmf.xtext-inbox>
Status:	CLOSED FIXED	QA Contact:
Severity:	normal
Priority:	P3	CC:	mail, sebastian.zarnekow, sven.efftinge
Version:	unspecified	Flags:	sven.efftinge: indigo+
Target Milestone:	SR2
Hardware:	PC
OS:	Windows XP
Whiteboard:

Description Christian Dietrich

2011-09-22 08:17:14 EDT

Build Identifier: 2.0.0 2.0.1 nightly from 2011-09-21

In Xtend create extensions are cached
if i want to use them at 2 different locations i have to inject the same instance e.g. by declaring the Xtend Class singleton.

Thus i will get (if i use the same injector e.g. from an running editor)
always the same instance of the Xtend Class.

This may lead to unexpected results/memory leaks during several generator runs. (e.g. call of the "generate" action)

i'd like to be able to explicitely clear this caches e.g. by getting a clearCaches method or something like that

We currently workaround this problem by clearing the caches using reflection.

btw the builderparticipant / igenerator suffer from this "leak" too.

Reproducible: Always

Comment 1 Sven Efftinge

2011-09-22 08:28:58 EDT

If you use the create extensions in a long running environment (i.e. in the IDE) you should obtain and discard a fresh instance using a Provider in order to control the lifecycle of the state.

However the ongoing refactoring will make the field visible and accessible.

Comment 2 Christian Dietrich

2011-09-22 08:30:42 EDT

Good to hear,
what will be the solution for the builderparticipant/igenerator: will i have to many call the clears there too?

~Christian

Comment 3 Sven Efftinge

2011-09-22 10:17:22 EDT

You should obtain a fresh instance for each transformation.

Comment 4 Christian Dietrich

2011-09-22 10:26:11 EDT

since builderparticipant and its use of igenerator are infrastructure provided by xtext it is hard to do it yourself besides cleaning up manually at the end of the dogenerate method.

Comment 5 Sven Efftinge

2011-09-22 10:34:35 EDT

Maybe I wasn't clear (or I misunderstood you ;-)):

I meant something like this:

class MyGenerator implements IGenerator {

  @Inject Provider<MyTransformationCode> transformerProvider

  def generate(Resoure res, IFileSystemAccess fsa) {
     transformerProvider.get().doTransformation(res, fsa)
  }

}

The lifecycle of the cache state is directly associated to the lifecycle of instances of the Xtend class containing create functions. That is how it is meant to be used.

Comment 6 Christian Dietrich

2011-09-22 10:48:18 EDT

Hi,

yes this will work but i still don't know how to then solve the singleton problem:

you have Xtend class A that has a createExtension createA
and you have XtendClasses B and C that use A.createA
how to make shure that B and C get the same instance
without declaring A as Singleton.
and if a is a singleton using a provider
won't help

Comment 7 Sven Efftinge

2011-09-22 10:55:54 EDT

You could
a) pass the instance around
b) marking it a singleton and explicitly clear the cache, when you think it's a good idea to do so.

Comment 8 Christian Dietrich

2011-09-22 10:58:01 EDT

Thats ok for me so far - never the less it still feels like a workarround

Comment 9 Sebastian Zarnekow

2011-10-12 07:28:32 EDT

The cache variable is now visible from within the Xtend class which allows to create a function that clears the cache explicitly.

Comment 10 Karsten Thoms

2017-09-19 17:39:47 EDT

Closing all bugs that were set to RESOLVED before Neon.0

Comment 11 Karsten Thoms

2017-09-19 17:51:03 EDT

Closing all bugs that were set to RESOLVED before Neon.0