Fix RSpec/DescribedClass to ignore *_eval and *_exec blocks

Author: sucicfilip

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - Fix a false positive for `RSpec/LeakyLocalVariable` when variables are used only in example metadata (e.g., skip messages). ([@ydah])
 - Fix a false positive for `RSpec/ScatteredSetup` when the hook is defined inside a class method. ([@d4rky-pl])
+- Fix a false positive for `RSpec/DescribedClass` inside dynamically evaluated blocks (`class_eval`, `module_eval`, `instance_eval`, `class_exec`, `module_exec`, `instance_exec`). ([@sucicfilip])
 
 ## 3.8.0 (2025-11-12)
 
@@ -1083,6 +1084,7 @@ Compatibility release so users can upgrade RuboCop to 0.51.0. No new features.
 [@smcgivern]: https://github.com/smcgivern
 [@splattael]: https://github.com/splattael
 [@stephannv]: https://github.com/stephannv
+[@sucicfilip]: https://github.com/sucicfilip
 [@swelther]: https://github.com/swelther
 [@t3h2mas]: https://github.com/t3h2mas
 [@tdeo]: https://github.com/tdeo

lib/rubocop/cop/rspec/described_class.rb

@@ -87,6 +87,8 @@ class DescribedClass < Base # rubocop:disable Metrics/ClassLength
             {
               (send (const nil? {:Class :Module :Struct}) :new ...)
               (send (const nil? :Data) :define ...)
+              (send _ {:class_eval :module_eval :instance_eval} ...)
+              (send _ {:class_exec :module_exec :instance_exec} ...)
             }
             ...
           )

spec/rubocop/cop/rspec/described_class_spec.rb

@@ -195,6 +195,34 @@ module MyModule
       RUBY
     end
 
+    it 'ignores class inside *_eval and *_exec blocks' do
+      expect_no_offenses(<<~RUBY)
+        RSpec.describe Foo do
+          before do
+            stub_const('Dummy', Class.new).class_eval do
+              Foo.new
+            end
+
+            stub_const('Dummy', Class.new).module_eval do
+              Foo.new
+            end
+
+            stub_const('Dummy', Class.new).instance_eval do
+              Foo.new
+            end
+
+            stub_const('Dummy', Class.new).class_exec do
+              Foo.new
+            end
+
+            stub_const('Dummy', Class.new).module_exec do
+              Foo.new
+            end
+          end
+        end
+      RUBY
+    end
+
     it 'takes class from innermost describe' do
       expect_offense(<<~RUBY)
         describe MyClass do