yeah, something fishy is happening there. I will take a look.
On 25 Jan 2017, at 18:31, phil@highoctane.be wrote:
pharo-win-i386-201701151442-c50dec0.zip
On Wed, Jan 25, 2017 at 3:57 PM, Esteban Lorenzano <estebanlm@gmail.com <mailto:estebanlm@gmail.com>> wrote: nevertheless it should be there in latests vms. which version are you using?
Esteban
On 25 Jan 2017, at 15:04, phil@highoctane.be <mailto:phil@highoctane.be> wrote:
Tried it and it returns false for this Windows VM.
Phil
On Wed, Jan 25, 2017 at 2:14 PM, Clément Bera <bera.clement@gmail.com <mailto:bera.clement@gmail.com>> wrote: I introduced the method #supportsWriteBarrier in Pharo 6.
You can backport it if you want:
VirtualMachine>>#supportsWriteBarrier "Answer whether the VM observes the per-object read-only flag and consequently aborts writes to inst vars of, and fails primitives that attempt to write, to read-only objects."
^(self parameterAt: 65) ifNil: [false] ifNotNil: [:param| "In older VMs this is a boolean reflecting MULTIPLE_BYTECODE_SETS" param isInteger "In newer VMs it is a set of integer flags, bit 1 of which is IMMUTABILITY" ifTrue: [param anyMask: 2] ifFalse: [false]]
On Wed, Jan 25, 2017 at 2:06 PM, phil@highoctane.be <mailto:phil@highoctane.be> <phil@highoctane.be <mailto:phil@highoctane.be>> wrote: The "latest" Windows VM I do use has no such method.
Virtual Machine --------------- C:\Users\Philippe\Dropbox\Sibelga\JiraAutomation\Pharo5.0\latestvm\pharo.exe CoInterpreter * VMMaker.oscog-eem.2090 uuid: 63a161b9-17e1-4911-a89a-1687d9ba9a1a Jan 15 2017 StackToRegisterMappingCogit * VMMaker.oscog-eem.2090 uuid: 63a161b9-17e1-4911-a89a-1687d9ba9a1a Jan 15 2017 VM: 201701151442 https://github.com/pharo-project/pharo-vm.git <https://github.com/pharo-project/pharo-vm.git> $ Date: Sun Jan 15 15:42:39 2017 +0100 $ Plugins: 201701151442 https://github.com/pharo-project/pharo-vm.git <https://github.com/pharo-project/pharo-vm.git> $
Win32 built on Jan 15 2017 15:59:52 CUT Compiler: 5.4.0 VMMaker versionString VM: 201701151442 https://github.com/pharo-project/pharo-vm.git <https://github.com/pharo-project/pharo-vm.git> $ Date: Sun Jan 15 15:42:39 2017 +0100 $ Plugins: 201701151442 https://github.com/pharo-project/pharo-vm.git <https://github.com/pharo-project/pharo-vm.git> $ CoInterpreter * VMMaker.oscog-eem.2090 uuid: 63a161b9-17e1-4911-a89a-1687d9ba9a1a Jan 15 2017 StackToRegisterMappingCogit * VMMaker.oscog-eem.2090 uuid: 63a161b9-17e1-4911-a89a-1687d9ba9a1a Jan 15 2017
<image.png>
On Wed, Jan 25, 2017 at 1:54 PM, Clément Bera <bera.clement@gmail.com <mailto:bera.clement@gmail.com>> wrote:
On Wed, Jan 25, 2017 at 11:35 AM, Norbert Hartl <norbert@hartl.name <mailto:norbert@hartl.name>> wrote: Does anyone know the state of immutability support in vm and image? The latest vm downloadable is compiled with
IMMUTABILITY=1
(Esteban said that). When I open a pharo6 image with this VM and do:
ASUser new setIsReadOnlyObject: true; name: 'foo'
with
ASUser>>#name: arg1 name := arg1
I don't get an exception. Is there something missing or am I not understanding?
Hi Norbert,
Thank you very much for looking read-only objects.
When mutating an instance variable, the VM triggers a call-back that by default does nothing. In your case, running your code does not raise an exception but the object should not be modified either. If you want an exception, you need to change the call-back code, i.e., the method Object>>#attemptToAssign: value withIndex: index. For example, you could write:
Object>>#attemptToAssign: value withIndex: index | process | self notify: 'object changed !'. process := Processor activeProcess. [ process suspendedContext: process suspendedContext sender ] forkAt: Processor activePriority + 1. Processor yield.
Then, your code should open a notification window with 'object changed', and proceeding keeps running the code without mutating the object.
One needs to build a ModificationTracker framework on top of the VM support I introduced. Multiple things are required, like default behavior in this call-back and in primitive failure code. I am willing to support and help anyone willing to build such a framework, but I won't build it myself.
If you have any other questions or if you find bug don't hesitate to ask further questions
Best,
PS: Make sure "Smalltalk vm supportsWriteBarrier" answers true in your system, if this is not the case it means the VM does not support read-only objects.
Clement
Norbert