Hi Marcel, it goes to Emergency Evaluator even when it doesn't lock up
too, but I think this is worth it if it saves the lock up cases; EE is
certainly better.  How should this interplay with the big red X
approach that Morphic uses?

On Sun, Apr 17, 2016 at 10:44 AM,  <commits at source.squeak.org> wrote:
> Marcel Taeumel uploaded a new version of Morphic to project The Trunk:
> http://source.squeak.org/trunk/Morphic-mt.1113.mcz
>
> ==================== Summary ====================
>
> Name: Morphic-mt.1113
> Author: mt
> Time: 17 April 2016, 5:44:23.036117 pm
> UUID: 1b36a4fb-13d9-f04f-8552-4048b9ac0439
> Ancestors: Morphic-mt.1112
>
> Improves robustness when facing erroneous drawing code that affects the debugger GUI. In that case, show primitive REPL instead of freezing the image.
>
> Note that there will soon be more code to recover from such serious errors.
>
> =============== Diff against Morphic-mt.1112 ===============
>
> Item was changed:
>   ----- Method: Debugger class>>morphicOpenOn:context:label:contents:fullView: (in category '*Morphic-opening') -----
> + morphicOpenOn: process context: context label: title contents: contentsStringOrNil fullView: full
> - morphicOpenOn: process context: context label: title contents: contentsStringOrNil fullView: bool
>         "Open a notifier in response to an error, halt, or notify. A notifier view just shows a short view of the sender stack and provides a menu that lets the user open a full debugger."
>
>         | errorWasInUIProcess debugger |
> +       ErrorRecursion ifTrue: [
> +               "self assert: process == Project current uiProcess -- DOCUMENTATION ONLY"
> +               ErrorRecursion := false.
> +               ^ Project current handleFatalDrawingError: title].
> +
> +       [ErrorRecursion not & Preferences logDebuggerStackToFile
> -       errorWasInUIProcess := Project current spawnNewProcessIfThisIsUI: process.
> -       [Preferences logDebuggerStackToFile
>                 ifTrue: [Smalltalk logSqueakError: title inContext: context]] on: Error do: [:ex | ex return: nil].
> +
> +       ErrorRecursion := true.
> +
> +       errorWasInUIProcess := Project current spawnNewProcessIfThisIsUI: process.
> +
> +       "Schedule debugging in deferred UI message because
> +               1) If process is the current UI process, it is already broken.
> +               2) If process is some other process, it must not execute UI code"
> +       Project current addDeferredUIMessage: [
> +               debugger := self new process: process controller: nil context: context.
> +               full
> +                       ifTrue: [debugger openFullNoSuspendLabel: title]
> +                       ifFalse: [debugger openNotifierContents: contentsStringOrNil label: title].
> +               debugger errorWasInUIProcess: errorWasInUIProcess.
> +
> +               "Try drawing the debugger tool at least once to avoid freeze."
> +               ActiveWorld displayWorldSafely.
> +
> +               ErrorRecursion := false.
> -       WorldState addDeferredUIMessage: [
> -               "schedule debugger in deferred UI message to address redraw
> -               problems after opening a debugger e.g. from the testrunner."
> -               [
> -                       debugger := self new process: process controller: nil context: context.
> -                       bool
> -                               ifTrue: [debugger openFullNoSuspendLabel: title]
> -                               ifFalse: [debugger openNotifierContents: contentsStringOrNil label: title].
> -                       debugger errorWasInUIProcess: errorWasInUIProcess.
> -               ] on: Error do: [:ex |
> -                               self primitiveError:
> -                                       'Original error: ',
> -                                       title asString, '.
> -       Debugger error: ',
> -                               ([ex description] on: Error do: ['a ', ex class printString]), ':'
> -                       ]
>         ].
>         process suspend.
>   !
>
>