Added GitVersion.Abstractions module

[arturcic]

Moving most of the interfaces from Core to Abstractions, made modules depend on Abstractions instead of Core

[mergify]

Thank you @arturcic for your contribution!

[asbjornu]

Sorry, but I don’t agree with this change. We don’t need to move interfaces out of Core, that makes it not be the core anymore.

[arturcic]

Core will change to Calculation, it will contain only the version calculation logic, eventually

[arturcic]

Sorry, but I don’t agree with this change. We don’t need to move interfaces out of Core, that makes it not be the core anymore.

The Abstractions module has the contracts defined, that means the modules we have (output and agents for now) will depend on the contracts. Now the implementations of those interfaces are defined in the specific module.

[arturcic]

@asbjornu please have a look here #3407 (comment)

[asbjornu]

Core will change to Calculation, it will contain only the version calculation logic, eventually

Don't you consider version calculation to be "core" to what GitVersion does?

The Abstractions module has the contracts defined, that means the modules we have (output and agents for now) will depend on the contracts. Now the implementations of those interfaces are defined in the specific module.

Sounds like the separation we already had with Core?

[arturcic]

Don't you consider version calculation to be "core" to what GitVersion does?

Yes, and only version calculation should be in core, all the other modules - like output, agents, maybe configuration, should not belong to core in my opinion. The version calculation code should know about the Options and the EffectiveConfiguration as inputs, and those should be provided/computed by the 'external modules', same for the output - GitVersionVariables, that is used by 'external modules'

Basically the Core takes input and gives back the output. It should not be aware how the input/output is prepared/used.

Now if we keep those interfaces and implementations in the Core then it has too many responsibilities. That's why I was saying that Core will eventually become Calculation. That's why I introduced the Abstractions (can be renamed to Contracts).

[arturcic]

I can revert this PR if you want to have a broader discussion on this refactoring.

[asbjornu]

Hm, I think I agree with almost everything you just wrote, so I have to take a more thorough look at this to understand exactly what it is you're writing compared to what this PR is actually doing.

[arturcic]

The PR is moving to that direction, not yet there