depguard: add current module name to allow list

[mirecl]

AS-IS: depguard/v2 automatic add current module name (from go.mod) in deny list.
TO-BE: depguard/v2 automatic add current module name (from go.mod) in allow list.

[boring-cyborg]

Hey, thank you for opening your first Pull Request !

[CLAassistant]

All committers have signed the CLA.

[mirecl]

@alexandear @ldez , i'm sure this will be a useful addition, what do you think?

[ldez]

Hello,

I think it will create confusion: it's better to let the user create it's own configuration.
Also, the way to get the go.mod is too naive and it will not work in some context.

I will decline this PR.

[mirecl]

@ldez, your logic is strange, all will continue to do this setting, add current module to allow list!

[ldez]

An example of a real configuration:

  depguard:
    rules:
      main:
        deny:
          - pkg: "github.com/instana/testify"
            desc: not allowed
          - pkg: "github.com/pkg/errors"
            desc: Should be replaced by standard lib errors package

As you can see the current module doesn't need to be added.

[mirecl]

But if you add at least 1 rule to the allowed list, then the current module becomes prohibited.

[ldez]

Yes because it's the way that depguard v2 works.