On 04 Nov 2013, at 00:01, Stéphane Ducasse <[email protected]> wrote:

> But marcus we are doing update all the time because this is the way we push 
> new updates daily.
> So I do not understand why this would be different?
> 

It happens due to strange things: updates that access the web and URLs change, 
for example.
Or in the past one problem was that it could overload squeak-source to load for 
hours and hours packages…

And it takes quite some care to keep it going: when *really* bad things happen, 
we now (once or twice in a year)
upload a fixed image that is than taken as the base. If you want to support 
“take pharo2 and update it to pharo3”,
(or even, take Pharo3 half a year ago…), then we need to put *a huge* (very 
huge) effort into making sure that
we never ever upload a hand-fixed image. 
This is a lot of work. 

And in addition, even that does not guarantee anything: you would need to 
actually test it… 



>> 
>>> no you dont do anything wrong, unfortunately from what I have been told the 
>>> update process is broken. Right now the best choices is to download 
>>> directly from pharo website 
>>> 
>> The problem is that how images are used is shifting: People used to use an 
>> image for a long time, updating the base from time to time while their code
>> was in the image.
>> 
>> These days, what people do is to have an automatic (and well defined) 
>> process that build a fresh image on
>>      -> base system is updated
>>      -> Own code commit
>> 
>> So e.g. I never retain images after I finish something. I commit, wait for 
>> the build system to tell me everything is green, and I throw the image
>> away. Images are transient things. 
>> 
>> This in turn means nobody uses updating, and this means that it is not 
>> tested. and everything not tested brakes after a while….
>> (In turn, everything we want to be sure works needs to be tested after every 
>> commit, but testing “updating every old version to the newest”
>> is not really testable, anayway…)
>> 
>> When we move to an image-bootstrap for the development of Pharo itself (I 
>> guess in Pharo4), we should really check what and how (and if) we
>> support updating existing images, or if we declare the image to be something 
>> that *always* be the result of a deterministic build process…
>> 
>>      Marcus
>> 
>> 
> 
> 


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