Do not report duplicate for shim or annotations classes redefining th…

…e parent class

Signed-off-by: Alexandre Terrasa <alexandre.terrasa@shopify.com>

lib/tapioca/helpers/rbi_files_helper.rb

@@ -174,7 +174,21 @@ def shims_or_todos_have_duplicates?(nodes, shim_rbi_dir:, todo_rbi_file:)
       shims_or_todos = extract_shims_and_todos(nodes, shim_rbi_dir: shim_rbi_dir, todo_rbi_file: todo_rbi_file)
       return false if shims_or_todos.empty?
 
+      not_shims_or_todos = nodes - shims_or_todos
       shims_or_todos_empty_scopes = extract_empty_scopes(shims_or_todos)
+
+      # We need to discard classes that are redefining the parent of a class
+      shims_or_todos_empty_scopes.select! do |scope|
+        # Empty modules are always duplicates
+        next true unless scope.is_a?(RBI::Class)
+
+        # Empty classes without parents are also duplicates
+        parent_name = scope.superclass_name
+        next true unless parent_name
+
+        # Empty classes that are not redefining the parent are also duplicates
+        not_shims_or_todos.any? { |node| node.is_a?(RBI::Class) && node.superclass_name == parent_name }
+      end
       return true unless shims_or_todos_empty_scopes.empty?
 
       mixins = extract_mixins(shims_or_todos)

spec/tapioca/cli/check_shims_spec.rb

@@ -295,6 +295,58 @@ class Qux
         refute_success_status(result)
       end
 
+      it "ignores duplicates that have a parent class" do
+        @project.write!("sorbet/rbi/gems/foo@1.0.0.rbi", <<~RBI)
+          class Foo
+          end
+          class Bar < Foo
+          end
+        RBI
+
+        @project.write!("sorbet/rbi/shims/foo.rbi", <<~RBI)
+          class Foo < Baz
+          end
+          class Bar < Baz
+          end
+        RBI
+
+        result = @project.tapioca("check-shims --no-payload")
+        assert_success_status(result)
+      end
+
+      it "detects duplicates that have a parent class" do
+        @project.write!("sorbet/rbi/gems/foo@1.0.0.rbi", <<~RBI)
+          class Foo
+          end
+          class Bar < Foo
+          end
+        RBI
+
+        @project.write!("sorbet/rbi/shims/foo.rbi", <<~RBI)
+          class Foo
+          end
+          class Bar < Foo
+          end
+        RBI
+
+        result = @project.tapioca("check-shims --no-payload")
+
+        assert_stderr_equals(<<~ERR, result)
+
+          Duplicated RBI for ::Foo:
+           * sorbet/rbi/shims/foo.rbi:1:0-2:3
+           * sorbet/rbi/gems/foo@1.0.0.rbi:1:0-2:3
+
+          Duplicated RBI for ::Bar:
+           * sorbet/rbi/shims/foo.rbi:3:0-4:3
+           * sorbet/rbi/gems/foo@1.0.0.rbi:3:0-4:3
+
+          Please remove the duplicated definitions from sorbet/rbi/shims and sorbet/rbi/todo.rbi
+        ERR
+
+        refute_success_status(result)
+      end
+
       it "detects duplicates from same shim file" do
         @project.write!("sorbet/rbi/gems/foo@1.0.0.rbi", <<~RBI)
           class Foo