David T. Lewis uploaded a new version of System to project The Trunk:
http://source.squeak.org/trunk/System-dtl.609.mcz

==================== Summary ====================

Name: System-dtl.609
Author: dtl
Time: 25 October 2013, 6:58:38.544 pm
UUID: fbe5d078-bc29-40f3-aed6-6e3fee445c27
Ancestors: System-cmm.608

As reported on the pharo list, there are no senders of DeepCopier>>isItTimeToCheckVariables. The method comment is from 1999. The value of NextVariableCheckTime was last updated in 2001. There are no senders in Squeak 3.2. This method is well past its expiration date, so get rid of it.

=============== Diff against System-cmm.608 ===============

Item was changed:
  Object subclass: #DeepCopier
  	instanceVariableNames: 'references uniClasses newUniClasses'
+ 	classVariableNames: ''
- 	classVariableNames: 'NextVariableCheckTime'
  	poolDictionaries: ''
  	category: 'System-Object Storage'!
  
  !DeepCopier commentStamp: 'tk 3/4/2003 19:39' prior: 0!
  DeepCopier does a veryDeepCopy.  
  
  It is a complete tree copy using a dictionary.  Any object that is in the tree twice is only copied once.  All references to the object in the copy of the tree will point to the new copy.  See Object|veryDeepCopy which calls (self veryDeepCopyWith: aDeepCopier).
  
  The dictionary of objects that have been seen, holds the correspondance (uniClass -> new uniClass).
  
  When a tree of morphs points at a morph outside of itself, that morph should not be copied.  Use our own kind of weak pointers for the 'potentially outside' morphs.   Default is that any new class will have all of its fields deeply copied.  If a field needs to be weakly copied, define veryDeepInner: and veryDeepFixupWith:.
       veryDeepInner: has the loop that actually copies the fields.  If a class defines its own copy of veryDeepInner: (to leave some fields out), then veryDeepFixupWith: will be called on that object at the end.  veryDeepInner: can compute an alternate object to put in a field.  (Object veryDeepCopyWith: discovers which superclasses did not define veryDeepInner:, and very deeply copies the variables defined in those classes).
  	To decide if a class needs veryDeepInner: and veryDeepFixupWith:, ask this about an instance:  If I duplicate this object, does that mean that I also want to make duplicates of the things it holds onto?  If yes, (i.e. a Paragraph does want a new copy of its Text) then do nothing.  If no, (i.e. an undo command does not want to copy the objects it acts upon), then define veryDeepInner: and veryDeepFixupWith:.
  	
  Here is an analysis for the specific case of a morph being held by another morph.  
  Does field X contain a morph (or a Player whose costume is a morph)?  If not, no action needed.
  Is the morph in field X already a submorph of the object?  Is it down lower in the submorph tree?
  	If so, no action needed.
  Could the morph in field X every appear on the screen (be a submorph of some other morph)?
  	If not, no action needed.
  	If it could, you must write the methods veryDeepFixupWith:   and   veryDeepInner:, and in them, refrain from sending veryDeepCopyWith: to the contents of field X.
  
  newUniClasses =   true in the normal case.  Every duplicated Player gets a new class.  When false, all duplicates will be siblings (sister instances) of existing players.
  
  
  ----- Things Ted is still considering -----
  Rule:  If a morph stores a uniClass class (Player 57) as an object in a field, the new uniClass will not be stored there.   Each uniClass instance does have a new class created for it.  (fix this by putting the old class in references and allow lookup?  Wrong if encounter it before seeing an instance?)
  
  Rule: If object A has object C in a field, and A says (^ C) for the copy, but object B has A in a normal field and it gets deepCopied, and A in encountered first, then there will be two copies of C.  (just be aware of it)
  
  Dependents are now fixed up.  Suppose a model has a dependent view.  In the DependentFields dictionary, model -> (view ...).  
  	If only the model is copied, no dependents are created (no one knows about the new model).  
  	If only the view is copied, it is inserted into DependentFields on the right side.  model -> (view  copiedView ...).  
  	If both are copied, the new model has the new view as its dependent.
  	If additional things depend on a model that is copied, the caller must add them to its dependents.
  !

Item was removed:
- ----- Method: DeepCopier>>intervalForChecks (in category 'like fullCopy') -----
- intervalForChecks
- 	"set delay interval for checking for new instance variables to 10 minutes. hg 11/23/1999"
- 
- 	^600
- !

Item was removed:
- ----- Method: DeepCopier>>isItTimeToCheckVariables (in category 'like fullCopy') -----
- isItTimeToCheckVariables
- 
- 	| now isIt |
- 	NextVariableCheckTime ifNil: [
- 		NextVariableCheckTime := Time totalSeconds.
- 		^ true].
- 	now := Time totalSeconds.
- 	isIt := NextVariableCheckTime < now.
- 	isIt ifTrue: ["update time for next check"
- 		NextVariableCheckTime := now + self intervalForChecks].
- 	^isIt
- !