Fix false positive in RSpec/LetSetup cop when let! variables are used in blocks declared in an outer context

Author: ydah

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Master (Unreleased)
 
+- Fix false positive in `RSpec/LetSetup` cop when `let!` variables are used in blocks declared in an outer context. ([@ydah])
+
 ## 3.8.0 (2025-11-12)
 
 - Add new cop `RSpec/LeakyLocalVariable`. ([@lovro-bikic])

lib/rubocop/cop/rspec/let_setup.rb

@@ -72,8 +72,9 @@ def on_block(node) # rubocop:disable InternalAffairs/NumblockHandler
         def unused_let_bang(node)
           child_let_bang(node) do |method_send, method_name|
             next if overrides_outer_let_bang?(node, method_name)
+            next if method_called_in_scope?(node, method_name.to_sym)
 
-            yield(method_send) unless method_called?(node, method_name.to_sym)
+            yield(method_send)
           end
         end
 
@@ -98,6 +99,24 @@ def outer_let_bang?(ancestor_node, method_name)
             end
           end
         end
+
+        def method_called_in_scope?(node, method_name)
+          method_called?(node, method_name) ||
+            method_called_in_parent_hooks?(node, method_name)
+        end
+
+        def method_called_in_parent_hooks?(node, method_name)
+          node.each_ancestor(:block).any? do |ancestor|
+            example_or_shared_group_or_including?(ancestor) &&
+              method_called_in_hooks?(ancestor, method_name)
+          end
+        end
+
+        def method_called_in_hooks?(node, method_name)
+          RuboCop::RSpec::ExampleGroup.new(node).hooks.any? do |hook|
+            method_called?(hook.to_node, method_name)
+          end
+        end
       end
     end
   end

spec/rubocop/cop/rspec/let_setup_spec.rb

@@ -257,4 +257,99 @@
       end
     RUBY
   end
+
+  it 'ignores let! used in parent after hook' do
+    expect_no_offenses(<<~RUBY)
+      describe 'Parent' do
+        after { variable.cleanup }
+
+        context 'Child' do
+          let!(:variable) { setup }
+          it { expect(true).to be true }
+        end
+      end
+    RUBY
+  end
+
+  it 'ignores let! used in parent before hook' do
+    expect_no_offenses(<<~RUBY)
+      describe 'Parent' do
+        before { variable.setup }
+
+        context 'Child' do
+          let!(:variable) { create }
+          it { expect(true).to be true }
+        end
+      end
+    RUBY
+  end
+
+  it 'ignores let! used in parent around hook' do
+    expect_no_offenses(<<~RUBY)
+      describe 'Parent' do
+        around { |example| variable.wrap { example.run } }
+
+        context 'Child' do
+          let!(:variable) { create }
+          it { expect(true).to be true }
+        end
+      end
+    RUBY
+  end
+
+  it 'complains when let! is not used anywhere' do
+    expect_offense(<<~RUBY)
+      describe 'Parent' do
+        context 'Child' do
+          let!(:variable) { setup }
+          ^^^^^^^^^^^^^^^ Do not use `let!` to setup objects not referenced in tests.
+          it { expect(true).to be true }
+        end
+      end
+    RUBY
+  end
+
+  it 'ignores let! used in nested example' do
+    expect_no_offenses(<<~RUBY)
+      describe 'Parent' do
+        context 'Child' do
+          let!(:variable) { setup }
+          it { expect(variable).to be_present }
+        end
+      end
+    RUBY
+  end
+
+  it 'ignores let! used in parent after hook with method call' do
+    expect_no_offenses(<<~RUBY)
+      describe 'Example' do
+        after do
+          authenticator.remove!
+        end
+
+        context 'nested' do
+          let!(:authenticator) { create_authenticator }
+
+          it 'does something' do
+            expect(true).to be true
+          end
+        end
+      end
+    RUBY
+  end
+
+  it 'ignores let! used in multiple parent levels' do
+    expect_no_offenses(<<~RUBY)
+      describe 'Level 0' do
+        after { variable.cleanup }
+
+        context 'Level 1' do
+          context 'Level 2' do
+            let!(:variable) { setup }
+            it { expect(true).to be true }
+          end
+        end
+      end
+    RUBY
+  end
 end