[Fix #8102] Consider class-length instead of block-length for Struct.new

CHANGELOG.md

@@ -9,6 +9,7 @@
 ### Changes
 
 * [#8646](https://github.com/rubocop-hq/rubocop/issues/8646): Faster find of all files in `TargetFinder` class which improves rubocop initial startup speed. ([@tleish][])
+* [#8102](https://github.com/rubocop-hq/rubocop/issues/8102): Consider class-length instead of block-length for `Struct.new`. ([@tejasbubane][])
 
 ## 0.92.0 (2020-09-25)
 

docs/modules/ROOT/pages/cops_metrics.adoc

@@ -57,6 +57,8 @@ You can set literals you want to fold with `CountAsOne`.
 Available are: 'array', 'hash', and 'heredoc'. Each literal
 will be counted as one line regardless of its actual size.
 
+NOTE: This cop does not apply for `Struct` definitions.
+
 === Examples
 
 ==== CountAsOne: ['array', 'heredoc']
@@ -165,6 +167,8 @@ You can set literals you want to fold with `CountAsOne`.
 Available are: 'array', 'hash', and 'heredoc'. Each literal
 will be counted as one line regardless of its actual size.
 
+NOTE: This cop also applies for `Struct` definitions.
+
 === Examples
 
 ==== CountAsOne: ['array', 'heredoc']

lib/rubocop/cop/metrics/block_length.rb

@@ -29,14 +29,16 @@ module Metrics
       #       content.
       #     HEREDOC
       #   end                 # 5 points
+      #
+      # NOTE: This cop does not apply for `Struct` definitions.
       class BlockLength < Base
         include CodeLength
 
         LABEL = 'Block'
 
         def on_block(node)
           return if excluded_method?(node)
-          return if node.class_constructor?
+          return if node.class_constructor? || node.struct_constructor?
 
           check_code_length(node)
         end

lib/rubocop/cop/metrics/class_length.rb

@@ -29,6 +29,8 @@ module Metrics
       #     HEREDOC
       #   end                 # 5 points
       #
+      #
+      # NOTE: This cop also applies for `Struct` definitions.
       class ClassLength < Base
         include CodeLength
 
@@ -37,17 +39,12 @@ def on_class(node)
         end
 
         def on_casgn(node)
-          class_definition?(node) do
-            check_code_length(node)
-          end
+          _scope, _name, block_node = *node
+          check_code_length(node) if block_node.class_definition?
         end
 
         private
 
-        def_node_matcher :class_definition?, <<~PATTERN
-          (casgn nil? _ (block (send (const {nil? cbase} :Class) :new) ...))
-        PATTERN
-
         def message(length, max_length)
           format('Class has too many lines. [%<length>d/%<max>d]',
                  length: length,

lib/rubocop/cop/mixin/hash_transform_method.rb

@@ -137,7 +137,7 @@ def transformation_uses_both_args?
       end
 
       # Internal helper class to hold autocorrect data
-      Autocorrection = Struct.new(:match, :block_node, :leading, :trailing) do # rubocop:disable Metrics/BlockLength
+      Autocorrection = Struct.new(:match, :block_node, :leading, :trailing) do
         def self.from_each_with_object(node, match)
           new(match, node, 0, 0)
         end

lib/rubocop/cop/variable_force/branch.rb

@@ -20,8 +20,6 @@ def self.of(target_node, scope: nil)
           nil
         end
 
-        # rubocop:disable Metrics/BlockLength
-
         # Abstract base class for branch classes.
         # A branch represents a conditional branch in a scope.
         #
@@ -42,8 +40,6 @@ def self.of(target_node, scope: nil)
         #     do_something     # no branch
         #   end
         Base = Struct.new(:child_node, :scope) do
-          # rubocop:enable Metrics/BlockLength
-
           def self.classes
             @classes ||= []
           end

spec/rubocop/cop/metrics/block_length_spec.rb

@@ -159,6 +159,27 @@
     end
   end
 
+  context 'when defining a Struct' do
+    it 'does not register an offense' do
+      expect_no_offenses(<<~'RUBY')
+        Person = Struct.new(:first_name, :last_name) do
+          def full_name
+            "#{first_name} #{last_name}"
+          end
+
+          def foo
+            a = 1
+            a = 2
+            a = 3
+            a = 4
+            a = 5
+            a = 6
+          end
+        end
+      RUBY
+    end
+  end
+
   context 'when CountComments is enabled' do
     before { cop_config['CountComments'] = true }
 

spec/rubocop/cop/metrics/class_length_spec.rb

@@ -201,4 +201,20 @@ class Test
       RUBY
     end
   end
+
+  context 'when inspecting a class defined with Struct.new' do
+    it 'registers an offense' do
+      expect_offense(<<~RUBY)
+        Foo = Struct.new(:foo, :bar) do
+        ^^^ Class has too many lines. [6/5]
+          a = 1
+          a = 2
+          a = 3
+          a = 4
+          a = 5
+          a = 6
+        end
+      RUBY
+    end
+  end
 end