Editor: lines instance variable is nil, do: sent to nil

[JurajKubelka]

System info

• DEV v0.8.374
• macOS Big Sur 11.1

  Steps to reproduce:

  Step 1: Open document

  In the World home tab, click on the Glamorous Toolkit document:

  

  Which results in the following view:

  

  Step 2: Open another document in the second pane

  Click on the moldable development link inside of the document. Maybe it is also necessary to click inside of the new document to change focus. I am not sure if the focus is important. It looks like the focus is not important.

  

  Step 3: Click inside of the first document

  Click in the area without the text. It looks like clicking inside of the text does not produce any issue.

  

  Issue

  Debugger

  

Debugger stack

UndefinedObject(Object)>>doesNotUnderstand: #distanceTo:
UndefinedObject>>doesNotUnderstand: #distanceTo:
BrEditorTextFlowLayout>>findClosestLineTo:
BrEditorTextFlowLayout>>findClosestChildOf:to:
BrTextEditorLineSegmentHolder>>explicitScreenToCursor:
BrTextEditorExplicitScreenToCursorTransformation>>evaluateOn:
BrTextEditorLineSegmentHolder>>screenToCursor:
BrTextEditorScreenToCursorHolderCommand>>executeOn:
BrTextEditorScreenToCursorHolderCommand(BrTextEditorHolderCommand)>>sendTo:
BlInfiniteElementDataSourceObserver>>onItemsEvent:
BlInfiniteDataSourceItemRangeEvent>>sendTo:
BlInfiniteElementDataSourceObserver(BlInfiniteDataSourceObserver)>>handleEvent:
BlHandlerAnnouncementSubscription>>deliver:
[ "Ensure delivery to remaining announcements" subscription deliver: anAnnouncement ] in SubscriptionRegistry>>deliver:to:startingAt: in Block: [ "Ensure delivery to remaining announcements" sub...etc...
BlockClosure>>ifCurtailed:
SubscriptionRegistry>>deliver:to:startingAt:
SubscriptionRegistry>>deliver:to:
SubscriptionRegistry>>deliver:
Announcer>>announce:
BlHandlerAnnouncerRegistry>>dispatchEvent:
BlDirectEventDispatcher>>dispatchEvent:next:
BlDirectEventDispatcher(BlEventDispatcher)>>dispatchEvent:
BrTextEditor(BlInfiniteDataSource)>>dispatchEvent:
BrTextEditor(BlInfiniteDataSource)>>notifyWithEvent:
BrTextEditor(BlInfiniteDataSource)>>notifyItems:event:
BrTextEditor>>enqueueHolderCommand:interval:
BrTextEditorScreenToCursorCommand>>explicitScreenToCursor:for:
BrTextEditorExplicitScreenToCursorTransformation>>evaluateOn:for:
BrTextEditorScreenToCursorCommand>>executeOn:
BrTextEditor>>enqueueCommand:

[JurajKubelka]

Another observation: It looks like after the error, the text editor behaves like selecting a text, despite the fact that I am just moving a cursor. The tab is anyway necessary to close, because it continue opening debuggers with the same issue in a loop.

[onierstrasz]

I am getting this issue frequently when I click in a Playground.