Exclude checks in specific namespaces

[AlessandroMinoccheri]

Feature Request

Add the possibility to exclude namespaces from expressions

Q	A
New Feature	yes
RFC	yes
BC Break	it depends

Summary

After further discussion in this issue: #480, it became clear that there's currently no standard or intuitive way to exclude specific namespaces in expressions like NotDependsOnTheseNamespaces.

This expression uses a variadic parameter in its constructor, which makes it difficult to introduce additional arguments—such as an "exclude" array to define namespaces that should be ignored during the check.

We currently see two potential paths forward:

1. Introduce a breaking change: Replace the variadic parameter with a standard array, allowing us to introduce a second parameter (e.g., for excluded namespaces). To maintain consistency, this change would need to be applied across all similar expressions, which could break existing implementations.
2. Introduce a new rule, such as ExcludeTheseNamespacesFromChecks, which would accept an array (or variadic arguments) of namespaces to be excluded. This would avoid breaking changes and keep existing rules intact.

Example:

$rules[] = Rule::allClasses()
    ->that(new ResideInOneOfTheseNamespaces('')) // yes, some classes are not namespaced
    ->andThat(new NotResideInTheseNamespaces('App\Shop'))
    ->should(new NotDependsOnTheseNamespaces('App\Shop'))
    ->exclude(new ExcludeTheseNamespacesFromChecks('App\Shop\ShopFacade'))
    ->because('Other modules should only access Shop through ShopFacade');

Or

$rules[] = Rule::allClasses()
    ->that(new ResideInOneOfTheseNamespaces('')) // yes, some classes are not namespaced
    ->andThat(new NotResideInTheseNamespaces('App\Shop'))
    ->should(new NotDependsOnTheseNamespaces('App\Shop'))
    ->excludeTheseNamespacesFromChecks('App\Shop\ShopFacade')
    ->because('Other modules should only access Shop through ShopFacade');

What do you think @fain182 @micheleorselli @pfazzi ?

[micheleorselli]

Introduce a breaking change: Replace the variadic parameter with a standard array, allowing us to introduce a second parameter (e.g., for excluded namespaces). To maintain consistency, this change would need to be applied across all similar expressions, which could break existing implementations.

The pros of this approach imo are:

• we do already have array rather than spread operator in other rule like MatchOneOfTheseNames and NotHaveDependencyOutsideNamespace, so the is no problem in consistency
• the fact we are specifying exclusion for this specific check is more explicit rather than having it for the whole rule
• the implementation is simpler because it affects only the internal implementation of the class NotDependsOnTheseNamespaces

The cons:

• potential bc break, but considering we can document it and it is unlikely for a project to have hundreds of rules, the impact of it should be small

I think for now it could be a good enough and unblock the possibility to write rule in the format

all classes outside namespace X should not access namespace X except for X/Facade

cc @AlessandroMinoccheri @fain182 @pfazzi