Hi Paul,

You can set the object to be "read only" (aka "immutable") and handle the exception.

E.g.

| u |

u := User named: 'Paul'.

u beReadOnlyObject.

[ "your code modifying u's state" ]

on: ModificationForbidden��

do: [ :ex |��

ex halt.

��"inspect state"��

u beWritableObject.

ex resume

Probably there is a better way to do this with slots, using default ones or subclassing `InstanceVariableSlot` for that instance only and halting on the `write:to:` method of it.

Regards,

Esteban A. Maringolo

El mi��., 2 ene. 2019 a las 15:45, PAUL DEBRUICKER via Pharo-users (<pharo-users@lists.pharo.org>) escribi��:

Hi -

Is there a way to haltOnChange or some such for an object?��

I have an instance that gets into a state I don't understand and would like to watch it or several of its inst vars for when they change.��

I could set a lot of #haltIf: statements and step through but hope someone has a better strategy

thanks & happy new year.

Paul