Only generate mixin RBIs for foreign constants

lib/tapioca/gem/events.rb

@@ -102,6 +102,8 @@ def initialize(symbol, constant, node)
       end
     end
 
+    class ForeignScopeNodeAdded < ScopeNodeAdded; end
+
     class MethodNodeAdded < NodeAdded
       extend T::Sig
 

lib/tapioca/gem/listeners/base.rb

@@ -17,6 +17,8 @@ def initialize(pipeline)
 
         sig { params(event: NodeAdded).void }
         def dispatch(event)
+          return if should_skip?(event)
+
           case event
           when ConstNodeAdded
             on_const(event)
@@ -42,6 +44,15 @@ def on_scope(event)
         sig { params(event: MethodNodeAdded).void }
         def on_method(event)
         end
+
+        sig { params(event: NodeAdded).returns(T::Boolean) }
+        def should_skip?(event)
+          # Some listeners do not have to take any action on certain events. For example,
+          # almost every listener should skip ForeignScopeNodeAdded events in order not to generate
+          # unnecessary RBIs for foreign constants. This method should be overridden by listener
+          # subclasses to skip events that are not relevant to them.
+          event.is_a?(Tapioca::Gem::ForeignScopeNodeAdded)
+        end
       end
     end
   end

lib/tapioca/gem/listeners/mixins.rb

@@ -95,6 +95,11 @@ def interesting_ancestors_of(constant)
             inherited_ancestors_ids.include?(object_id_of(mod))
           end
         end
+
+        sig { params(event: NodeAdded).returns(T::Boolean) }
+        def should_skip?(event)
+          false
+        end
       end
     end
   end

lib/tapioca/gem/pipeline.rb

@@ -71,11 +71,20 @@ def push_const(symbol, constant, node)
         @events << Gem::ConstNodeAdded.new(symbol, constant, node)
       end
 
-      sig { params(symbol: String, constant: Module, node: RBI::Scope).void.checked(:never) }
+      sig do
+        params(symbol: String, constant: Module, node: RBI::Scope).void.checked(:never)
+      end
       def push_scope(symbol, constant, node)
         @events << Gem::ScopeNodeAdded.new(symbol, constant, node)
       end
 
+      sig do
+        params(symbol: String, constant: Module, node: RBI::Scope).void.checked(:never)
+      end
+      def push_foreign_scope(symbol, constant, node)
+        @events << Gem::ForeignScopeNodeAdded.new(symbol, constant, node)
+      end
+
       sig do
         params(
           symbol: String,
@@ -256,7 +265,12 @@ def compile_module(name, constant, foreign_constant: false)
             RBI::Module.new(name)
           end
 
-        push_scope(name, constant, scope)
+        if foreign_constant
+          push_foreign_scope(name, constant, scope)
+        else
+          push_scope(name, constant, scope)
+        end
+
         @root << scope
       end
 

spec/tapioca/cli/gem_spec.rb

@@ -1074,10 +1074,55 @@ def foo(a, b, c, d, e, f, g, h); end
           assert_success_status(result)
         end
 
+        it "must do mixin attribution properly" do
+          # This is pattern is taken from the private `typed_parameters` gem.
+          typed_parameters = mock_gem("typed_parameters", "0.3.0") do
+            write("lib/typed_parameters.rb", <<~RUBY)
+              require "action_controller"
+              module TypedParameters
+              end
+              # This dynamic mixin should be generated in the gem RBI
+              ActionController::Parameters.include(TypedParameters)
+            RUBY
+          end
+
+          @project.require_real_gem("actionpack", "6.1.4.4")
+          @project.require_mock_gem(typed_parameters)
+
+          @project.bundle_install
+
+          response = @project.tapioca("gem actionpack typed_parameters")
+
+          assert_includes(response.out, "Compiled actionpack")
+          assert_includes(response.out, "Compiled typed_parameters")
+
+          # TODO: Uncomment when addressing part 2 of tapioca#890
+          # actionpack_rbi = @project.read("sorbet/rbi/gems/actionpack@6.1.4.4.rbi")
+          # actionpack RBI should have nothing in it about `TypedParameters`
+          # refute_includes(actionpack_rbi, "TypedParameters")
+
+          assert_project_file_equal("sorbet/rbi/gems/typed_parameters@0.3.0.rbi", <<~RBI)
+            # typed: true
+
+            # DO NOT EDIT MANUALLY
+            # This is an autogenerated file for types exported from the `typed_parameters` gem.
+            # Please instead update this file by running `bin/tapioca gem typed_parameters`.
+
+            class ActionController::Parameters
+              include ::TypedParameters
+            end
+
+            module TypedParameters; end
+          RBI
+        end
+
         it "must generate RBIs for constants defined in a different gem but with mixins in this gem" do
           foo = mock_gem("foo", "0.0.1") do
             write("lib/foo.rb", <<~RBI)
-              class Foo; end
+              class Foo
+                def baz; end
+                def buzz; end
+              end
             RBI
           end
 

spec/tapioca/gem/pipeline_spec.rb

@@ -542,9 +542,6 @@ class String
           include ::Foo::Bar
           extend ::JSON::Ext::Generator::GeneratorMethods::String::Extend
         end
-
-        String::BLANK_RE = T.let(T.unsafe(nil), Regexp)
-        String::ENCODED_BLANKS = T.let(T.unsafe(nil), Concurrent::Map)
       RBI
 
       assert_equal(output, compile)
@@ -597,9 +594,6 @@ class String
           include ::Foo::Bar
           extend ::JSON::Ext::Generator::GeneratorMethods::String::Extend
         end
-
-        String::BLANK_RE = T.let(T.unsafe(nil), Regexp)
-        String::ENCODED_BLANKS = T.let(T.unsafe(nil), Concurrent::Map)
       RBI
 
       assert_equal(output, compile)