The problem is that the script you evaluate will update the Compiler...
New updates will remove unused variables before the script is finished...
I tried to solve the problem by introducing an intermediate step:
- 1) publish the modified methods in an update.mcm (I reintroduced the
missing vars)
- 2) only then remove the inst. var.
(See the recent serie of Compiler versions 270->274

This did not solve anything because there are always cases when you launch
the script from an older image (typically from Squeak 4.4, 4.3 or even
older)
The same old Compiler instance is used during all the process and it must
be unmodified during the process, otherwise, undefined behavior (SEGV
included)...

I see one way to workaround this:
1) clone the Compiler class
2) instantiate the clone
3) let the clone evaluate

In fact, to be safer we should clone the whole hierarchy, but you could 1st
try simply with Compiler...


2013/9/25 Bob Arning <arning315 at comcast.net>

>  Just type
>
> PositionableStream>>#fileInAnnouncing:
>
> and explore it. Look for the literal pointing to the compiler (literal8
> here). Toggle that open and toggle open the value. Look at the
> instanceVariables - does it still have sourceStream?
>
> As to the explorer, did you open one? Is it still open? (The PointerFinder
> says it is) Could it have been open when the image was last saved?
>
>
> Also, you could do
>
> Behavior allSubInstances select: [ :e | (e asString findString:
> 'Compiler') > 0]
>
> Do you get: an OrderedCollection(ClosureCompilerTest CompilerTest
> CompilerExceptionsTest CompilerNotifyingTest
> CompilerSyntaxErrorNotifyingTest Compiler ClosureCompilerTest class
> CompilerTest class CompilerExceptionsTest class CompilerNotifyingTest class
> CompilerSyntaxErrorNotifyingTest class Compiler class)
>
>
> Cheers,
> Bob
>
>  On 9/25/13 7:31 AM, Frank Shearar wrote:
>
> I don't know how I would do that. The bytecode just says pushLit: Compiler.
>
> But if I say Compiler allInstances collect: [:c | c instVarNamed:
> 'cue'] I see {nil . a CompilationCue . a CompilationCue}. That first
> one's a problem! Further, my image has an ObjectExplorer (!) hanging
> onto that Compiler, coming from I don't know where.
>
> frank
>
> On 25 September 2013 11:53, Bob Arning <arning315 at comcast.net> <arning315 at comcast.net> wrote:
>
>  If you inspect
>
> PositionableStream>>#fileInAnnouncing:
>
> and look at the literal for Compiler, does it look to be pointing to the new
> or old Compiler?
>
> Cheers,
> Bob
>
> On 9/25/13 6:12 AM, Frank Shearar wrote:
>
> I'm running with Compiler-nice.274.
>
> What's weirder is in that top stack frame (Compiler >>
> #evaluate:in:to:notifying:ifFailed:logged: the following all show up
> as red, because they're references to instvars that don't exist:
> class, sourceStream, context, requestor.
>
> That's because the CompiledMethod that's running is not actually the
> right CompiledMethod! It's from some ancient pre-CompilationCue
> Compiler instance. Or at least so I suspect because that Compiler
> instance has a nil 'cue' instvar.
>
> If it helps, the PointerFinder says this of the offending context:
>
> globals: Environment
> declarations: IdentityDictionary
> #World -> PasteUpMorph
> submorphs: Array
> 1: SystemWindow
> model: ObjectExplorer
> currentSelection: ObjectExplorerWrapper
> item: CompiledMethod
>
> In contrast, PointerFinder on: (Compiler >>
> #evaluate:in:to:notifying:ifFail:logged:) says:
>
> CLASS: SmalltalkImage class
> superclass: Object class
> subclasses: Array
> 445: Compiler class
> methodDict: MethodDictionary
> array: Array
> 39: CompiledMethod.
>
>
>
>
>
>
>
>
>
>
>
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