I wasn't sure if this should go into the release at this stage so I submitted to the inbox instead. It seems pretty safe to me, and fixes a major annoyance while debugging, so if others try and find it safe we might apply it now. Otherwise I'll push it early after the 4.4 release.

- Bert -

On 2012-11-16, at 19:47, commits at source.squeak.org wrote:

> Bert Freudenberg uploaded a new version of Tools to project The Inbox:
> http://source.squeak.org/inbox/Tools-bf.429.mcz
> 
> ==================== Summary ====================
> 
> Name: Tools-bf.429
> Author: bf
> Time: 16 November 2012, 8:47:08.199 pm
> UUID: cabe1021-05b4-45f3-9141-989bcb580add
> Ancestors: Tools-eem.428
> 
> Fix changes in debugger getting lost when reverting to method from an inner block. As reported by Aran Lunzer:
> 
> Set up the following method on some class:
> 
> bugger
>  | a1 |
>  a1 := 0.
>  [ 2 / a1 ] value
> 
> then send   <class> new bugger
> 
> In the walkback, try changing the last line to
> 
>  [ b1:=2.  2 / a1 ] value
> 
> (oops - said b1 instead of a1...)
> 
> Debugger asks if it's ok to revert to the method in which the block was defined.  Say ok.  Then it asks about adding b1 as a new variable (NB: at this stage, the code edits have already disappeared).  Then cancel, intending to fix the variable name.  But your edits are lost.
> 
> =============== Diff against Tools-eem.428 ===============
> 
> Item was changed:
>  ----- Method: Debugger>>contents:notifying: (in category 'accessing') -----
>  contents: aText notifying: aController
>  	"The retrieved information has changed and its source must now be updated.
>  	 In this case, the retrieved information is the method of the selected context."
>  	| result selector classOfMethod category h ctxt newMethod |
>  	contextStackIndex = 0 ifTrue:
>  		[^false].
>  	self selectedContext isExecutingBlock ifTrue:
>  		[h := self selectedContext activeHome.
>  		 h ifNil:
>  			[self inform: 'Method for block not found on stack, can''t edit and continue'.
>  			 ^false].
>  		 (self confirm: 'I will have to revert to the method from\which this block originated.  Is that OK?' withCRs) ifFalse:
>  			[^false].
> + 		self resetContext: h changeContents: false.
> - 		self resetContext: h.
>  		"N.B. Only reset the contents if the compilation succeeds.  If contents are reset
>  		 when compilation fails both compiler error message and modifications are lost."
>  		(result := self contents: aText notifying: aController) ifTrue:
>  			[self contentsChanged].
>  		^result].
> 
>  	classOfMethod := self selectedClass.
>  	category := self selectedMessageCategoryName.
>  	selector := self selectedClass newParser parseSelector: aText.
>  	(selector == self selectedMessageName
>  	 or: [(self selectedMessageName beginsWith: 'DoIt')
>  		and: [selector numArgs = self selectedMessageName numArgs]]) ifFalse:
>  		[self inform: 'can''t change selector'.
>  		 ^false].
>  	selector := classOfMethod
>  				compile: aText
>  				classified: category
>  				notifying: aController.
>  	selector ifNil: [^false]. "compile cancelled"
>  	contents := aText.
>  	newMethod := classOfMethod compiledMethodAt: selector.
>  	newMethod isQuick ifTrue:
>  		[self down.
>  		 self selectedContext jump: (self selectedContext previousPc - self selectedContext pc)].
>  	ctxt := interruptedProcess popTo: self selectedContext.
>  	ctxt == self selectedContext
>  		ifFalse:
>  			[self inform: 'Method saved, but current context unchanged\because of unwind error. Click OK to see error' withCRs]
>  		ifTrue:
>  			[newMethod isQuick ifFalse:
>  				[interruptedProcess
>  					restartTopWith: newMethod;
>  				 	stepToSendOrReturn].
>  			contextVariablesInspector object: nil].
>  	self resetContext: ctxt.
>  	Smalltalk isMorphic ifTrue:
>  		[World
>  			addAlarm: #changed:
>  			withArguments: #(contentsSelection)
>  			for: self
>  			at: (Time millisecondClockValue + 200)].
>  	^true!
> 
> Item was added:
> + ----- Method: Debugger>>resetContext:changeContents: (in category 'private') -----
> + resetContext: aContext changeContents: aBoolean
> + 	"Used when a new context becomes top-of-stack, for instance when the
> + 	method of the selected context is re-compiled, or the simulator steps or
> + 	returns to a new method. There is room for much optimization here, first
> + 	to save recomputing the whole stack list (and text), and secondly to avoid
> + 	recomposing all that text (by editing the paragraph instead of recreating it)."
> + 
> + 	| oldContext |
> + 	oldContext := self selectedContext.
> + 	self newStack: aContext contextStack.
> + 	self changed: #contextStackList.
> + 	self contextStackIndex: 1 oldContextWas: oldContext.
> + 	aBoolean ifTrue: [self contentsChanged].
> + !
> 
>