Address encapsulation challenges in abstract classes about language

[rrousselGit]

Concrete has to be in the same "library" as Abstract.

Either put them in the same file, or have both share a part/part of relationship

[eernstg]

I find it very unappealing that it is possible to call a method that is not implemented in a static language without a compile time error

That was my motivation for creating this issue: dart-lang/linter#2938. You can check out the reasons given there for preferring that programs break at run time. I'd still prefer to have at least a notification at compile time.

[rubenferreira97]

I know since I am declaring two libraries (each file is a library) I can't access private properties/methods. I was asking this question because declaring both as the same library don't seem to model well for a feature based project.

Look at this example:

abstract.dart
feature1/
  concrete1.dart
feature2/
  concrete2.dart

Why would concrete1 and concrete2 be part of the same library? I would prefer a feature to be a library instead.

[mateusfccp]

I don't know if I understood well what you mean. Doesn't @protected works for you?

[rubenferreira97]

@mateusfccp AFAIK, @protected is just an annotation and don't solve my problem if both classes are declared on different files/libraries.

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I have another issue with this example that the Dart team may explain. I find it very unappealing that it is possible to call a method that is not implemented in a static language without a compile time error (I understand why it happens, I just don't think that's good design). Given a class (e.g. Abstract) with a private abstract method (e.g. _aInt) shouldn't be a compile error to extend it from a different library? If is in the same library it should be mandatory to override it (which already happens).

[mateusfccp]

@mateusfccp AFAIK, @protected is just an annotation and don't solve my problem if both classes are declared on different files/libraries.

You have to use it in a public method/getter. Then you will be warned if you use it in an inappropriate place.