On Thu, 3 Jan 2019 at 20:01, Konrad Hinsen via Pharo-users < pharo-users@lists.pharo.org> wrote:
> Dear Pharo experts, > > I am wondering if there is a good way to deal with singleton objects > whose value needs to be updated following changes in the code that > initializes it. > > Following the model of many examples in Pharo itself, I have defined a > singleton class with a uniqueInstance method for accessing (and creating > if necessary) the single instance, and a method "reset" marked as a > script to set the uniqueInstance back to nil when required, i.e. after > source code changes make the prior value inappropriate. > > This works very well, as long as I don't forget to do the reset, which > has already caused me a few hours of debugging time. Worse, suppose > someone else is using my project in progress, pulling changes from my > GitHub repo once per week. That person cannot know if the latest changes > require a singleton reset. More importantly, users shouldn't have to > know about such internal details at all. > > So is there a way to do the reset automatically whenever a new version > of my package is loaded into an image? > > Thanks in advance, > Konrad. > You might use a Baseline #postLoadDoIt: https://github.com/pharo-open-documentation/pharo-wiki/blob/master/General/Baselines.md Consider that a person pulling your changes cannot know if you have upgraded the library versions of any dependencies, so always updating via a Baseline might be a reasonable expectation. But that doesn't help you while developing within the one image. cheers -ben
