Not only my eyes are old, my brain too: here is the original intention of Monty:So it avoids file existence test in pre-condition, not in post-condition...
https://github.com/OpenSmalltalk/opensmalltalk- vm/pull/140/commits/ c1db1eb40b73373b4e4fe6541cda74 c8c742edc7
I swear I had seen other changes about passing failure status back to image for avoiding post-condition tests, but maybe it was not in this batch of changes.
Maybe check what happens in case someone did not update the VM properly before applying the image changes...Forget about all I wrote before, the changes definitely deserve a proper review.2017-08-29 1:36 GMT+02:00 tim Rowledge <tim@rowledge.org>:
> On 28-08-2017, at 11:47 AM, Nicolas Cellier <nicolas.cellier.aka.nice@gmail.com > wrote:
> Main request was to avoid case of race condition that can happen when separating the action (like opening a file) from the query in case of failure (like was file unwritable?), because another concurrent program might have changed the file system status in between (think of concurrent squeak images creating concurrent /tmp/foobar.baz for example).
Oh, *that* problem. I hate that. It’s such a stupid bit of (mis)design. I think I’ve been complaining about that for around 30 years…
>
> I have already integrated the necessary VM changes, but it remains to integrate image side changes.
> Last time I checked there were unecessary changes mixed that I'd preferred to see discussed here, and the fallback code might not work in older VM, then I came short of spare time...
> But in any cases, there are too many .mcz roting in inbox, so I'm glad another pair of eyes analyze the changes.
It’s all very well Torvalds declaring that all bugs are shallow with enough pairs of eyes, *if* you have enough pairs of eyes. We need more.
tim
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tim Rowledge; tim@rowledge.org; http://www.rowledge.org/tim
Strange OpCodes: RSC: Rewind System Clock