Hi Dave,

I think the best would be if SystemTracer used the mirror primitives (See 
Context's mirror primitives method category), primitive 110 (#object:eqeq:) 
in this case, so that proxies like MCPackageInEnvironment can't affect it.

Levente

On Sun, 13 May 2018, David T. Lewis wrote:

> This update feels a bit hacky to me with its test for a specific selector, so
> better or clearer solutions are welcome. Meanwhile, the prior behavior was
> corrupting identity dictionaries, which seems like a Bad Thing, so I put
> this fix (along with a new unit test) directly into trunk.
>
> The problem showed up as I was trying to get SystemTracer64 working again on
> V3 images, so it was not an easy thing to debug :-/
>
> Dave
>
> On Sun, May 13, 2018 at 11:14:39PM +0000, commits at source.squeak.org wrote:
>> David T. Lewis uploaded a new version of Monticello to project The Trunk:
>> http://source.squeak.org/trunk/Monticello-dtl.682.mcz
>> 
>> ==================== Summary ====================
>> 
>> Name: Monticello-dtl.682
>> Author: dtl
>> Time: 13 May 2018, 7:14:27.068827 pm
>> UUID: 76fc84e6-7e2b-4a6a-af6b-2d02d11c38eb
>> Ancestors: Monticello-nice.681
>> 
>> Sending perform: #== with: anObject to an instance of MCPackageInEnvironment should test identity of the actual instance, not the MCPackage to which it refers. If this is not so, a PluggableDictionary will fail when doing identity checks on its keys, as is the case for a SystemTracer adding all objects to its oop dictionary.
>> 
>> Implement MCPackageInEnvironment>>perform:with: such that performing #== will call primitivePerform, and all other selectors are delegated to the MCPackage as before.
>> 
>> =============== Diff against Monticello-nice.681 ===============
>> 
>> Item was added:
>> + ----- Method: MCPackageInEnvironment>>perform:with: (in category 'delegating') -----
>> + perform: aSymbol with: anObject
>> + 	"If aSymbol is #== then the sender is trying to perform an identity comparison.
>> + 	This cannot be delegated, because the delegate will be a different object.
>> + 	Implement perform:with: here to protect for this case. An important example
>> + 	is the case of PluggableDictionary, which relies on perform:with: to implement
>> + 	comparisons for an identity dictionary."
>> + 
>> + 	aSymbol == #==
>> + 		ifTrue: [ ^self privatePerform: aSymbol with: anObject ]
>> + 		ifFalse: [ ^package perform: aSymbol with: anObject "as per doesNotUnderStand:" ]
>> + !
>> 
>> Item was added:
>> + ----- Method: MCPackageInEnvironment>>privatePerform:with: (in category 'delegating') -----
>> + privatePerform: aSymbol with: anObject
>> + 	"aSymbol is #== and the sender is trying to perform an identity comparison.
>> + 	Invoke primitivePerform."
>> + 
>> + 	<primitive: 83>
>> + 	^ self primitiveFailed!
>> 
>>