Merge pull request #12543 from koic/fix_false_positives_for_style_has…

…h_each_methods

[Fix #12540] Fix false positives for `Style/HashEachMethods`

changelog/fix_false_positives_for_style_hash_each_methods.md

@@ -0,0 +1 @@
+* [#12540](https://github.com/rubocop/rubocop/issues/12540): Fix false positives for `Style/HashEachMethods` when rest block argument of `Enumerable#each` method is used. ([@koic][])

lib/rubocop/cop/style/hash_each_methods.rb

@@ -111,11 +111,11 @@ def unused_block_arg_exist?(node, block_arg)
           lvar_sources = node.body.each_descendant(:lvar).map(&:source)
 
           if block_arg.mlhs_type?
-            block_arg.each_descendant(:arg).all? do |block_arg|
-              lvar_sources.none?(block_arg.source)
+            block_arg.each_descendant(:arg, :restarg).all? do |block_arg|
+              lvar_sources.none?(block_arg.source.delete_prefix('*'))
             end
           else
-            lvar_sources.none?(block_arg.source)
+            lvar_sources.none?(block_arg.source.delete_prefix('*'))
           end
         end
 

spec/rubocop/cop/style/hash_each_methods_spec.rb

@@ -81,6 +81,14 @@
         expect_no_offenses('foo.each { |(_, k), v| do_something(k, v) }')
       end
 
+      it 'does not register an offense when the destructed rest value block arguments of `Enumerable#each` method are used' do
+        expect_no_offenses('foo.each { |k, (_, *v)| do_something(k, *v) }')
+      end
+
+      it 'does not register an offense when the destructed rest key block arguments of `Enumerable#each` method are used' do
+        expect_no_offenses('foo.each { |(_, *k), v| do_something(*k, v) }')
+      end
+
       it 'does not register an offense when the single block argument of `Enumerable#each` method is used' do
         expect_no_offenses('foo.each { |e| do_something(e) }')
       end
@@ -89,6 +97,36 @@
         expect_no_offenses('foo.each { |(k, v)| do_something(e) }')
       end
 
+      it 'does not register an offense when the rest value block argument of `Enumerable#each` method is used' do
+        expect_no_offenses('foo.each { |k, *v| do_something(k, *v) }')
+      end
+
+      it 'does not register an offense when the rest key block argument of `Enumerable#each` method is used' do
+        expect_no_offenses('foo.each { |*k, v| do_something(*k, v) }')
+      end
+
+      it 'registers an offense when the rest value block argument of `Enumerable#each` method is unused' do
+        expect_offense(<<~RUBY)
+          foo.each { |k, *v| do_something(*v) }
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `each_value` instead of `each` and remove the unused `k` block argument.
+        RUBY
+
+        expect_correction(<<~RUBY)
+          foo.each_value { |*v| do_something(*v) }
+        RUBY
+      end
+
+      it 'registers an offense when the rest key block argument of `Enumerable#each` method is unused' do
+        expect_offense(<<~RUBY)
+          foo.each { |*k, v| do_something(*k) }
+          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `each_key` instead of `each` and remove the unused `v` block argument.
+        RUBY
+
+        expect_correction(<<~RUBY)
+          foo.each_key { |*k| do_something(*k) }
+        RUBY
+      end
+
       it 'registers an offense when the value block argument of `Enumerable#each` method is unused' do
         expect_offense(<<~RUBY)
           foo.each { |k, unused_value| do_something(k) }