Discard all when I have zero metadata raises an arror

[ElsaLogier]

How I did and reproduced it :

• New Pharo image (Official distribution Pharo 12.0)
• Create a new package with a class and methods
• Open iceberg and add a new repository
• Add the package
• Click on "Discard All"

[ElsaLogier]

IceNoCommit(Object)>>doesNotUnderstand: #shortId
IceTipDiscardAllChangesPreviewBrowser>>loadCommitShortId
IceTipDiscardAllChangesPreviewBrowser>>initializePresenters
IceTipDiscardAllChangesPreviewBrowser(SpPresenter)>>initializePrivateHooks
IceTipDiscardAllChangesPreviewBrowser(SpPresenter)>>initialize
IceTipDiscardAllChangesPreviewBrowser(IceTipBrowser)>>initialize
IceTipDiscardAllChangesPreviewBrowser class(SpPresenter class)>>newApplication:model:
IceTipDiscardAllChangesPreviewBrowser class(SpPresenter class)>>on:
IceTipDiscardAllChangesPreviewBrowser class>>onRepository:
IceTipDiscardChangesCommand>>execute
IceTipSpCommand(CmCommandDecorator)>>execute
[ aCommand execute ] in IceTipToolbarButtonStrategy(IceTipCommandToPresenterBuildingStrategy)>>resultOn: in Block: [ aCommand execute ]
FullBlockClosure(BlockClosure)>>cull:
SpMorphicToolbarButtonAdapter>>execute
SpToolbarButtonMorph(PluggableButtonMorph)>>performAction:
[:m |
(m containsPoint: evt cursorPoint) ifTrue: [m enabled ifTrue: [ m performAction: evt ]]] in SpToolbarButtonMorph(PluggableButtonMorph)>>mouseUp: in Block: [:m |...
Array(SequenceableCollection)>>do:
SpToolbarButtonMorph(PluggableButtonMorph)>>mouseUp:
SpToolbarButtonMorph(Morph)>>handleMouseUp:
MouseButtonEvent>>sentTo:
SpToolbarButtonMorph(Morph)>>handleEvent:
SpToolbarButtonMorph(Morph)>>handleFocusEvent:
[
result := focusHolder handleFocusEvent: transformedEvent.
] in HandMorph>>sendFocusEvent:to:clear: in Block: [...
FullBlockClosure(BlockClosure)>>on:do:
WorldMorph>>becomeActiveDuring:
HandMorph>>sendFocusEvent:to:clear:
HandMorph>>sendEvent:focus:clear:
HandMorph>>sendMouseEvent:
HandMorph>>handleEvent:
HandMorph>>processEvents
[:h |
self activeHand: h.
h processEvents.
self activeHand: nil.
] in WorldState>>doOneCycleFor: in Block: [:h |...
Array(SequenceableCollection)>>do:
WorldState>>handsDo:
WorldState>>doOneCycleFor:
WorldMorph>>doOneCycleNow
WorldMorph>>doOneCycle
[
| extraWorldsToDraw |
extraWorldsToDraw := ExtraWorldListMutex critical: [
self extraWorldList ].
extraWorldsToDraw do: [ :world | world doOneCycle ].

	(self currentWorld isNotNil and: [
		 (extraWorldsToDraw includes: self currentWorld) not ]) ifTrue: [
		self currentWorld doOneCycle ] ] in WorldMorph class>>doOneCycle in Block: [...

FullBlockClosure(BlockClosure)>>ensure:
WorldState class>>doDrawCycleWith:
WorldMorph class>>doOneCycle
MorphicRenderLoop>>doOneCycle
MorphicRenderLoop>>doOneCycleWhile:
[ MorphicRenderLoop new doOneCycleWhile: [ true ] ] in MorphicUIManager>>spawnNewProcess in Block: [ MorphicRenderLoop new doOneCycleWhile: [ tru[..]
[self value.
"IMPORTANT: Do not step over next line of code. See method comments for details"
Processor terminateRealActive] in FullBlockClosure(BlockClosure)>>newProcess in Block: [self value....

[Ducasse]

We can reproduce it Pharo 13 (Pharo-13.0.0+SNAPSHOT.build.297.sha.9d19b62922b7fc72f44387254700dafd12c8c4a3
)

[Ducasse]

We defined

IceNoCommit >> shortId

	^ 'nocommit id'

It does not raise an error anymore and the caller is the following one.

initializePresenters 

	super initializePresenters.
	
	diffPanel
		leftLabel: 'Working Copy (Image)';
		rightLabel: 'Commit to load: ', self loadCommitShortId

Now I do not know if adding shortId on IceNoCommit is a good idea.

[Ducasse]

@tesonep do you think that this is safe? I cannot simply run locally the tests