[Enh]: Start if Needed on uniqueInstance Access

[seandenigris]

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[akgrant43]

Hi @seandenigris ,

I there's a few points to consider:

• There's existing code that uses #uniqueInstance returning nil to test whether a new application instance should be created with specific configuration.
• #start will raise an exception if called with the application started (with an inappropriate error message).
• We can't be sure that this won't negatively affect other users.

Instead of modifying #uniqueInstance, I'd add another method, e.g. #runningInstance, that always returns a started instance.

What do you think?

[seandenigris]

• There's existing code that uses #uniqueInstance returning nil to test whether a new application instance should be created with specific configuration.

Ah interesting. It sounds like the model is a bit more complex than I thought. That doesn't sound like the Singleton pattern as I understand it. I wonder if #uniqueInstance is even the right name. It may be misleading because it classically is sure to return something useful i.e. the singleton instance.

• #start will raise an exception if called with the application started (with an inappropriate error message).

Wouldn't the application be sure not be started if #uniqueInstance is nil?

• We can't be sure that this won't negatively affect other users.

Are there other users? Should I propose upstream and see if anyone objects?

Instead of modifying #uniqueInstance, I'd add another method, e.g. #runningInstance, that always returns a started instance.

I don't care too much, but lazy-initialized #uniqueInstance seems to be a common pattern and the "least surprising".

[akgrant43]

Hi Sean,

Wouldn't the application be sure not be started if #uniqueInstance is nil?

Doh! You're correct, of course.

I think that PBApplication started out as a singleton, however we want to be able to run multiple instances, but the class hasn't gone through the proper refactoring. So I've merged this in.

Thanks!