Issue 3262 in pharo: Don't cache the debugger's debuggerMap, it's not safe.

Status: Accepted
Owner: stephane.ducasse
Labels: Milestone-1.2

New issue 3262 by stephane.ducasse: Don't cache the debugger's debuggerMap,  
it's not safe.
http://code.google.com/p/pharo/issues/detail?id=3262

http://lists.squeakfoundation.org/pipermail/packages/2010-August/003602.html

Name: Tools-eem.258
Ancestors: Tools-eem.257

Don't cache the debugger's debuggerMap, its not safe.
Add preference for and support of opening a debugger for an error
in a background process when the UI process is busy.


====================================================



Eliot Miranda uploaded a new version of Tools to project The Trunk:
http://source.squeak.org/trunk/Tools-eem.258.mcz

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

Name: Tools-eem.258
Author: eem
Time: 14 August 2010, 6:45:20.412 pm
UUID: 261ba269-1565-45b1-9f7b-b6ce8cee312c
Ancestors: Tools-eem.257

Don't cache the debugger's debuggerMap, its not safe.
Add preference for and support of opening a debugger for an error
in a background process when the UI process is busy.

=============== Diff against Tools-eem.257 ===============

Item was added:
+ ----- Method: Debugger  
class>>interruptUIProcessIfBlockedOnErrorInBackgroundProcess: (in  
category 'preferences') -----
+ interruptUIProcessIfBlockedOnErrorInBackgroundProcess: aBoolean
+ InterruptUIProcessIfBlockedOnErrorInBackgroundProcess := aBoolean!

Item was changed:
   CodeHolder subclass: #Debugger
+ instanceVariableNames: 'interruptedProcess interruptedController  
contextStack contextStackTop contextStackIndex contextStackList  
receiverInspector contextVariablesInspector externalInterrupt proceedValue  
selectingPC savedCursor isolationHead failedProject errorWasInUIProcess  
labelString message'
+ classVariableNames: 'ContextStackKeystrokes ErrorRecursion  
InterruptUIProcessIfBlockedOnErrorInBackgroundProcess'
- instanceVariableNames: 'interruptedProcess interruptedController  
contextStack contextStackTop contextStackIndex contextStackList  
receiverInspector contextVariablesInspector externalInterrupt proceedValue  
selectingPC debuggerMap savedCursor errorWasInUIProcess labelString message'
- classVariableNames: 'ContextStackKeystrokes ErrorRecursion'
    poolDictionaries: ''
    category: 'Tools-Debugger'!

   !Debugger commentStamp: '<historical>' prior: 0!
   I represent the machine state at the time of an interrupted process. I  
also represent a query path into the state of the process. The debugger is  
typically viewed through a window that views the stack of suspended  
contexts, the code for, and execution point in, the currently selected  
message, and inspectors on both the receiver of the currently selected  
message, and the variables in the current context.

   Special note on recursive errors:
   Some errors affect Squeak's ability to present a debugger.  This is  
normally an unrecoverable situation.  However, if such an error occurs in  
an isolation layer, Squeak will attempt to exit from the isolation layer  
and then present a debugger.  Here is the chain of events in such a  
recovery.

    * A recursive error is detected.
    * The current project is queried for an isolationHead
    * Changes in the isolationHead are revoked
    * The parent project of isolated project is returned to
    * The debugger is opened there and execution resumes.

   If the user closes that debugger, execution continues in the outer  
project and layer.  If, after repairing some damage, the user proceeds from  
the debugger, then the isolationHead is re-invoked, the failed project is  
re-entered, and execution resumes in that world. !

Item was added:
+ ----- Method: Debugger class>>ifPreferredInterruptUIProcessIfBlocked: (in  
category 'private') -----
+ ifPreferredInterruptUIProcessIfBlocked: errorWasInUIProcess
+ | sema |
+ errorWasInUIProcess ifTrue:
+ [^self].
+ self interruptUIProcessIfBlockedOnErrorInBackgroundProcess ifFalse:
+ [^self].
+ "Only interrupt the UI if it is unresponsive (and so is doing something  
that needs
+ interrupting).  Test using addDeferredUIMessage: to see if it is  
running UI activities."
+ sema := Semaphore new.
+ Project current addDeferredUIMessage: [sema signal].
+ (sema waitTimeoutMSecs: 100) ifTrue:
+ [[Project current interruptName: 'Interrupt from Background Error']  
fork]
+
+ "| s |
+ s := Semaphore new.
+ [self assert: 0 > 1000. s signal] fork.
+ s wait"!

Item was changed:
   ----- Method: Debugger class>>openOn:context:label:contents:fullView: (in  
category 'opening') -----
   openOn: 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."

+ | controller errorWasInUIProcess block |
- | controller errorWasInUIProcess  |
    Smalltalk isMorphic
    ifTrue: [errorWasInUIProcess := Project spawnNewProcessIfThisIsUI:  
process]
    ifFalse: [controller := ScheduledControllers activeControllerProcess ==  
process
    ifTrue: [ScheduledControllers activeController]].
+ block := [
- WorldState addDeferredUIMessage: [
    [ | debugger |

    debugger := self new process: process controller: controller context:  
context.
    Smalltalk isMorphic
    ifTrue: ["schedule debugger in deferred UI message to address redraw
    problems after opening a debugger e.g. from the testrunner."
    "WorldState addDeferredUIMessage: ["bool
    ifTrue: [debugger openFullNoSuspendLabel: title]
    ifFalse: [debugger openNotifierContents: contentsStringOrNil label:  
title]]
    ifFalse: ["deferred UI message would require special controller in  
MVC"
    bool
    ifTrue: [debugger openFullNoSuspendLabel: title]
    ifFalse: [debugger openNotifierContents: contentsStringOrNil label:  
title]].
    debugger errorWasInUIProcess: errorWasInUIProcess.
    Preferences logDebuggerStackToFile ifTrue: [
    Smalltalk logError: title inContext: context to: 'SqueakDebug.log'].
    Smalltalk isMorphic
    ifFalse: [ScheduledControllers searchForActiveController "needed  
since openNoTerminate (see debugger #open...) does not set up  
activeControllerProcess if activeProcess (this fork) is not the current  
activeControllerProcess (see #scheduled:from:)"].
    ] on: Error do: [:ex |
    self primitiveError:
    'Orginal error: ',
    title asString, '.
    Debugger error: ',
    ([ex description] on: Error do: ['a ', ex class printString]), ':'
    ]
    ].
+ self ifPreferredInterruptUIProcessIfBlocked: errorWasInUIProcess.
+ Project current addDeferredUIMessage: block.
+ process suspend!
- process suspend.
- !

Item was changed:
   ----- Method: Debugger>>debuggerMap (in category 'accessing') -----
   debuggerMap
+ ^self selectedContext debuggerMap!
- ^debuggerMap ifNil:
- [debuggerMap := self selectedContext debuggerMap].!

Item was added:
+ ----- Method: Debugger  
class>>interruptUIProcessIfBlockedOnErrorInBackgroundProcess (in  
category 'preferences') -----
+ interruptUIProcessIfBlockedOnErrorInBackgroundProcess
+ <preference: 'Interrupt UI process on background error'
+ category: 'debug'
+ description: 'When enabled, the debugger will interrupt the UI process  
if an error occurs in a background process and the UI process is blocked.'
+ type: #Boolean>
+ ^InterruptUIProcessIfBlockedOnErrorInBackgroundProcess ifNil: [false]!

====================================================

Comment #1 on issue 3262 by stephane.ducasse: Don't cache the debugger's  
debuggerMap, it's not safe.
http://code.google.com/p/pharo/issues/detail?id=3262

related to Issue 2818