On Wed, Jan 25, 2017 at 4:42 PM, Denis Kudriashov <dionisiydk@gmail.com> wrote:
Another question Clement.
I found that current method doing something strange:
attemptToAssign: value withIndex: index process := Processor activeProcess. [ process suspendedContext: process suspendedContext sender ] forkAt: Processor activePriority + 1. Processor yield. "CAN'T REACH"
Could you comment why new process needed here? I just check simple version with error and it works:
attemptToAssign: value withIndex: index ^self error: 'modification failed'.
Also if I will modify #contents: as "*^*contents:=newValue" then following code is working well:
o := ValueHolder new. o beReadOnlyObject. [o contents: #test] on: Error do: [:err | err resumeUnchecked: #done]. "=> #done"
So I not understand the problem described in method comment.
Hi Denis, I will look into this case tomorrow, it looks like a bug. Thanks for reporting. For the Process hack, it's because the call-back was designed to return no value. It may look like it works when returning a value but you will have uncommon crashes.
2017-01-25 16:21 GMT+01:00 Denis Kudriashov <dionisiydk@gmail.com>:
2017-01-25 15:52 GMT+01:00 Clément Bera <bera.clement@gmail.com>:
Overall, you need to: - change the code of all numbered primitives mutating objects (such as at:put:) so that when they fail because of a read-only object they call the modification tracker framework.
I think it is for future.
But now behaviour is just inconsistent because making object readonly breaks any app using it *silently*. Also I see that instVarAt:put: will raise error instead of skipping it. So two ways to modify object lead to different behavior. It's not good.
My conclusion: it must be error by default. Something like this:
Object>>#attemptToAssign: value withIndex: index (ModificationForbidden for: self at: index with: value) signal
It is not fix completely inconsistence with #instVarAt:put: but at least they both will fail.
By the way I was supprized that failed #instVarAt:put: shows "bad receiver" in primitive *er* variable (<primitive: 174 error: *ec*>). Is "bad receiver" is always about mutability? And if not then how we will distinguish different cases?