Object>>doesNotUnderstand:

Hello,

I found method doesNotUnderstand have very strange implementation

Object>>doesNotUnderstand: aMessage
      | exception resumeValue |
    (exception := MessageNotUnderstood new)
        message: aMessage;
        receiver: self.
    resumeValue := exception signal.
    ^exception reachedDefaultHandler
        ifTrue: [aMessage sentTo: self]
        ifFalse: [resumeValue]

When Error has no handlers #defaultAction is executed. For MessageNotUnderstood #defaultAction is UnhandledError signal. And for UnhandledError #defaultAction is opening debugger.
If you change it to do nothing (^self) you get infinite loop on any MessageNotUnderstood signal.
It is because "ifTrue" branch executed in doesNotUnderstood method and message resend to receiver.

Why method implemented such way? Why it is differ from ProtoObject implementation. I think It's bug implementation.

I found this problem when I try implement stuff to turn off openning debugger on unhandled error (and write it to log)

UnhandledError>>defaultAction
    "The current computation is terminated. The cause of the error should be logged or reported to the user. If the program is operating in an interactive debugging environment the computation should be suspended and the debugger activated."
    ^ToolSet debugError: exception.

ToolSet class>>debugError: anError

    "Handle an otherwise unhandled error"
    self default ifNil:[ | ctx |
        Smalltalk
            logError: anError description
            inContext: (ctx := anError signalerContext)
            to: 'PharoDebug.log'.
        self inform: (anError description, String cr, ctx shortStack).
        ^anError return].
    ^self default debugError: anError

I just implement subclass of StandartToolSet with empty method #debugError:. Then I do "ToolSet default: MyToolSet". And now unhandled errors raise infinit loop and never return.

I fix that by:

MyToolSet>>debugError: anError
   anError class = MessageNotUnderstand ifTrue: [anError reachedDefaultHandler: true].

I think this is hack. But it is work. No errors show to user.And all work good.

What do you think?

Best regards,
Denis



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Pharo-project mailing list
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2010/7/27 Denis Kudriashov <[hidden email]>

Hello,

I found method doesNotUnderstand have very strange implementation

Object>>doesNotUnderstand: aMessage
      | exception resumeValue |
    (exception := MessageNotUnderstood new)
        message: aMessage;
        receiver: self.
    resumeValue := exception signal.
    ^exception reachedDefaultHandler
        ifTrue: [aMessage sentTo: self]
        ifFalse: [resumeValue]

When Error has no handlers #defaultAction is executed. For MessageNotUnderstood #defaultAction is UnhandledError signal. And for UnhandledError #defaultAction is opening debugger.
If you change it to do nothing (^self) you get infinite loop on any MessageNotUnderstood signal.
It is because "ifTrue" branch executed in doesNotUnderstood method and message resend to receiver.

Why method implemented such way? Why it is differ from ProtoObject implementation. I think It's bug implementation.

This is intentional.  Martin's reply is one half of the issue, that you want to be able to proceed after defining a method in  the debugger.  The otehr half is that you want to be able to catch doesNotUnderstand: in an exception handler and proceed with a result, e.g.

[nil zork]

on: MessageNotUnderstood

do: [:ex|

ex message selector == #zork ifTrue:

[ex resume: #ok].

ex pass]

evaluates to #ok.

 

I found this problem when I try implement stuff to turn off openning debugger on unhandled error (and write it to log)

UnhandledError>>defaultAction
    "The current computation is terminated. The cause of the error should be logged or reported to the user. If the program is operating in an interactive debugging environment the computation should be suspended and the debugger activated."
    ^ToolSet debugError: exception.

ToolSet class>>debugError: anError

    "Handle an otherwise unhandled error"
    self default ifNil:[ | ctx |
        Smalltalk
            logError: anError description
            inContext: (ctx := anError signalerContext)
            to: 'PharoDebug.log'.
        self inform: (anError description, String cr, ctx shortStack).
        ^anError return].
    ^self default debugError: anError

I just implement subclass of StandartToolSet with empty method #debugError:. Then I do "ToolSet default: MyToolSet". And now unhandled errors raise infinit loop and never return.

I fix that by:

MyToolSet>>debugError: anError
   anError class = MessageNotUnderstand ifTrue: [anError reachedDefaultHandler: true].

I think this is hack. But it is work. No errors show to user.And all work good.

What do you think?

I think that the bug is that you haven't modified the system to quit on an UnhandledException.  i.e. in a headless context control should never get back to the doesNotUnderstand: method if the MessageNotUnderstood exception is not caught.  How should one continue after an unhandled error?

HTH

Eliot

Best regards,
Denis



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Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

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I think that the bug is that you haven't modified the system to quit on an UnhandledException.  i.e. in a headless context control should never get back to the doesNotUnderstand: method if the MessageNotUnderstood exception is not caught.  How should one continue after an unhandled error?

With my approach I have "null object message eating" behavior. And when any unhandled errors raised in system user will see nothing. Only log file will contain it.

2010/7/28 Eliot Miranda <[hidden email]>

2010/7/27 Denis Kudriashov <[hidden email]>

Hello,

I found method doesNotUnderstand have very strange implementation

Object>>doesNotUnderstand: aMessage
      | exception resumeValue |
    (exception := MessageNotUnderstood new)
        message: aMessage;
        receiver: self.
    resumeValue := exception signal.
    ^exception reachedDefaultHandler
        ifTrue: [aMessage sentTo: self]
        ifFalse: [resumeValue]

When Error has no handlers #defaultAction is executed. For MessageNotUnderstood #defaultAction is UnhandledError signal. And for UnhandledError #defaultAction is opening debugger.
If you change it to do nothing (^self) you get infinite loop on any MessageNotUnderstood signal.
It is because "ifTrue" branch executed in doesNotUnderstood method and message resend to receiver.

Why method implemented such way? Why it is differ from ProtoObject implementation. I think It's bug implementation.

This is intentional.  Martin's reply is one half of the issue, that you want to be able to proceed after defining a method in  the debugger.  The otehr half is that you want to be able to catch doesNotUnderstand: in an exception handler and proceed with a result, e.g.

[nil zork]

on: MessageNotUnderstood

do: [:ex|

ex message selector == #zork ifTrue:

[ex resume: #ok].

ex pass]

evaluates to #ok.

 

I found this problem when I try implement stuff to turn off openning debugger on unhandled error (and write it to log)

UnhandledError>>defaultAction
    "The current computation is terminated. The cause of the error should be logged or reported to the user. If the program is operating in an interactive debugging environment the computation should be suspended and the debugger activated."
    ^ToolSet debugError: exception.

ToolSet class>>debugError: anError

    "Handle an otherwise unhandled error"
    self default ifNil:[ | ctx |
        Smalltalk
            logError: anError description
            inContext: (ctx := anError signalerContext)
            to: 'PharoDebug.log'.
        self inform: (anError description, String cr, ctx shortStack).
        ^anError return].
    ^self default debugError: anError

I just implement subclass of StandartToolSet with empty method #debugError:. Then I do "ToolSet default: MyToolSet". And now unhandled errors raise infinit loop and never return.

I fix that by:

MyToolSet>>debugError: anError
   anError class = MessageNotUnderstand ifTrue: [anError reachedDefaultHandler: true].

I think this is hack. But it is work. No errors show to user.And all work good.

What do you think?

I think that the bug is that you haven't modified the system to quit on an UnhandledException.  i.e. in a headless context control should never get back to the doesNotUnderstand: method if the MessageNotUnderstood exception is not caught.  How should one continue after an unhandled error?

HTH

Eliot

Best regards,
Denis



_______________________________________________
Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

_______________________________________________
Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

_______________________________________________
Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

I think that the bug is that you haven't modified the system to quit on an UnhandledException.  i.e. in a headless context control should never get back to the doesNotUnderstand: method if the MessageNotUnderstood exception is not caught.  How should one continue after an unhandled error?

With my approach I have "null object message eating" behavior. And when any unhandled errors raised in system user will see nothing. Only log file will contain it.

2010/7/28 Eliot Miranda <[hidden email]>

2010/7/27 Denis Kudriashov <[hidden email]>

Hello,

I found method doesNotUnderstand have very strange implementation

Object>>doesNotUnderstand: aMessage
      | exception resumeValue |
    (exception := MessageNotUnderstood new)
        message: aMessage;
        receiver: self.
    resumeValue := exception signal.
    ^exception reachedDefaultHandler
        ifTrue: [aMessage sentTo: self]
        ifFalse: [resumeValue]

When Error has no handlers #defaultAction is executed. For MessageNotUnderstood #defaultAction is UnhandledError signal. And for UnhandledError #defaultAction is opening debugger.
If you change it to do nothing (^self) you get infinite loop on any MessageNotUnderstood signal.
It is because "ifTrue" branch executed in doesNotUnderstood method and message resend to receiver.

Why method implemented such way? Why it is differ from ProtoObject implementation. I think It's bug implementation.

This is intentional.  Martin's reply is one half of the issue, that you want to be able to proceed after defining a method in  the debugger.  The otehr half is that you want to be able to catch doesNotUnderstand: in an exception handler and proceed with a result, e.g.

[nil zork]

on: MessageNotUnderstood

do: [:ex|

ex message selector == #zork ifTrue:

[ex resume: #ok].

ex pass]

evaluates to #ok.

 

I found this problem when I try implement stuff to turn off openning debugger on unhandled error (and write it to log)

UnhandledError>>defaultAction
    "The current computation is terminated. The cause of the error should be logged or reported to the user. If the program is operating in an interactive debugging environment the computation should be suspended and the debugger activated."
    ^ToolSet debugError: exception.

ToolSet class>>debugError: anError

    "Handle an otherwise unhandled error"
    self default ifNil:[ | ctx |
        Smalltalk
            logError: anError description
            inContext: (ctx := anError signalerContext)
            to: 'PharoDebug.log'.
        self inform: (anError description, String cr, ctx shortStack).
        ^anError return].
    ^self default debugError: anError

I just implement subclass of StandartToolSet with empty method #debugError:. Then I do "ToolSet default: MyToolSet". And now unhandled errors raise infinit loop and never return.

I fix that by:

MyToolSet>>debugError: anError
   anError class = MessageNotUnderstand ifTrue: [anError reachedDefaultHandler: true].

I think this is hack. But it is work. No errors show to user.And all work good.

What do you think?

I think that the bug is that you haven't modified the system to quit on an UnhandledException.  i.e. in a headless context control should never get back to the doesNotUnderstand: method if the MessageNotUnderstood exception is not caught.  How should one continue after an unhandled error?

HTH

Eliot

Best regards,
Denis



_______________________________________________
Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

_______________________________________________
Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

This is intentional.  Martin's reply is one half of the issue, that you want to be able to proceed after defining a method in  the debugger.  The otehr half is that you want to be able to catch doesNotUnderstand: in an exception handler and proceed with a result, e.g.

[nil zork]

on: MessageNotUnderstood

do: [:ex|

ex message selector == #zork ifTrue:

[ex resume: #ok].

ex pass]

evaluates to #ok.

This all work correct with ProtoObject implementation

ProtoObject>>doesNotUnderstand: aMessage

    ^ MessageNotUnderstood new
        message: aMessage;
        receiver: self;
        signal

28 июля 2010 г. 0:48:18 UTC+4 пользователь dionisiydk <[hidden email]> написал:

I think that the bug is that you haven't modified the system to quit on an UnhandledException.  i.e. in a headless context control should never get back to the doesNotUnderstand: method if the MessageNotUnderstood exception is not caught.  How should one continue after an unhandled error?

With my approach I have "null object message eating" behavior. And when any unhandled errors raised in system user will see nothing. Only log file will contain it.

2010/7/28 Eliot Miranda <[hidden email]>

2010/7/27 Denis Kudriashov <[hidden email]>

Hello,

I found method doesNotUnderstand have very strange implementation

Object>>doesNotUnderstand: aMessage
      | exception resumeValue |
    (exception := MessageNotUnderstood new)
        message: aMessage;
        receiver: self.
    resumeValue := exception signal.
    ^exception reachedDefaultHandler
        ifTrue: [aMessage sentTo: self]
        ifFalse: [resumeValue]

When Error has no handlers #defaultAction is executed. For MessageNotUnderstood #defaultAction is UnhandledError signal. And for UnhandledError #defaultAction is opening debugger.
If you change it to do nothing (^self) you get infinite loop on any MessageNotUnderstood signal.
It is because "ifTrue" branch executed in doesNotUnderstood method and message resend to receiver.

Why method implemented such way? Why it is differ from ProtoObject implementation. I think It's bug implementation.

This is intentional.  Martin's reply is one half of the issue, that you want to be able to proceed after defining a method in  the debugger.  The otehr half is that you want to be able to catch doesNotUnderstand: in an exception handler and proceed with a result, e.g.

[nil zork]

on: MessageNotUnderstood

do: [:ex|

ex message selector == #zork ifTrue:

[ex resume: #ok].

ex pass]

evaluates to #ok.

 

I found this problem when I try implement stuff to turn off openning debugger on unhandled error (and write it to log)

UnhandledError>>defaultAction
    "The current computation is terminated. The cause of the error should be logged or reported to the user. If the program is operating in an interactive debugging environment the computation should be suspended and the debugger activated."
    ^ToolSet debugError: exception.

ToolSet class>>debugError: anError

    "Handle an otherwise unhandled error"
    self default ifNil:[ | ctx |
        Smalltalk
            logError: anError description
            inContext: (ctx := anError signalerContext)
            to: 'PharoDebug.log'.
        self inform: (anError description, String cr, ctx shortStack).
        ^anError return].
    ^self default debugError: anError

I just implement subclass of StandartToolSet with empty method #debugError:. Then I do "ToolSet default: MyToolSet". And now unhandled errors raise infinit loop and never return.

I fix that by:

MyToolSet>>debugError: anError
   anError class = MessageNotUnderstand ifTrue: [anError reachedDefaultHandler: true].

I think this is hack. But it is work. No errors show to user.And all work good.

What do you think?

I think that the bug is that you haven't modified the system to quit on an UnhandledException.  i.e. in a headless context control should never get back to the doesNotUnderstand: method if the MessageNotUnderstood exception is not caught.  How should one continue after an unhandled error?

HTH

Eliot

Best regards,
Denis



_______________________________________________
Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

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Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

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[hidden email]
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2010/7/27 Denis Kudriashov <[hidden email]>

This is intentional.  Martin's reply is one half of the issue, that you want to be able to proceed after defining a method in  the debugger.  The otehr half is that you want to be able to catch doesNotUnderstand: in an exception handler and proceed with a result, e.g.

[nil zork]

on: MessageNotUnderstood

do: [:ex|

ex message selector == #zork ifTrue:

[ex resume: #ok].

ex pass]

evaluates to #ok.

This all work correct with ProtoObject implementation

ProtoObject>>doesNotUnderstand: aMessage

    ^ MessageNotUnderstood new
        message: aMessage;
        receiver: self;
        signal

Right, but you can't redefine and continue.  The Object implementation does both.  It used to only allow redefinition, not catching.

28 июля 2010 г. 0:48:18 UTC+4 пользователь dionisiydk <[hidden email]> написал:

I think that the bug is that you haven't modified the system to quit on an UnhandledException.  i.e. in a headless context control should never get back to the doesNotUnderstand: method if the MessageNotUnderstood exception is not caught.  How should one continue after an unhandled error?

With my approach I have "null object message eating" behavior. And when any unhandled errors raised in system user will see nothing. Only log file will contain it.

2010/7/28 Eliot Miranda <[hidden email]>

2010/7/27 Denis Kudriashov <[hidden email]>

Hello,

I found method doesNotUnderstand have very strange implementation

Object>>doesNotUnderstand: aMessage
      | exception resumeValue |
    (exception := MessageNotUnderstood new)
        message: aMessage;
        receiver: self.
    resumeValue := exception signal.
    ^exception reachedDefaultHandler
        ifTrue: [aMessage sentTo: self]
        ifFalse: [resumeValue]

When Error has no handlers #defaultAction is executed. For MessageNotUnderstood #defaultAction is UnhandledError signal. And for UnhandledError #defaultAction is opening debugger.
If you change it to do nothing (^self) you get infinite loop on any MessageNotUnderstood signal.
It is because "ifTrue" branch executed in doesNotUnderstood method and message resend to receiver.

Why method implemented such way? Why it is differ from ProtoObject implementation. I think It's bug implementation.

This is intentional.  Martin's reply is one half of the issue, that you want to be able to proceed after defining a method in  the debugger.  The otehr half is that you want to be able to catch doesNotUnderstand: in an exception handler and proceed with a result, e.g.

[nil zork]

on: MessageNotUnderstood

do: [:ex|

ex message selector == #zork ifTrue:

[ex resume: #ok].

ex pass]

evaluates to #ok.

 

I found this problem when I try implement stuff to turn off openning debugger on unhandled error (and write it to log)

UnhandledError>>defaultAction
    "The current computation is terminated. The cause of the error should be logged or reported to the user. If the program is operating in an interactive debugging environment the computation should be suspended and the debugger activated."
    ^ToolSet debugError: exception.

ToolSet class>>debugError: anError

    "Handle an otherwise unhandled error"
    self default ifNil:[ | ctx |
        Smalltalk
            logError: anError description
            inContext: (ctx := anError signalerContext)
            to: 'PharoDebug.log'.
        self inform: (anError description, String cr, ctx shortStack).
        ^anError return].
    ^self default debugError: anError

I just implement subclass of StandartToolSet with empty method #debugError:. Then I do "ToolSet default: MyToolSet". And now unhandled errors raise infinit loop and never return.

I fix that by:

MyToolSet>>debugError: anError
   anError class = MessageNotUnderstand ifTrue: [anError reachedDefaultHandler: true].

I think this is hack. But it is work. No errors show to user.And all work good.

What do you think?

I think that the bug is that you haven't modified the system to quit on an UnhandledException.  i.e. in a headless context control should never get back to the doesNotUnderstand: method if the MessageNotUnderstood exception is not caught.  How should one continue after an unhandled error?

HTH

Eliot

Best regards,
Denis



_______________________________________________
Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

_______________________________________________
Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project

_______________________________________________
Pharo-project mailing list
[hidden email]
http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project