Fix a false positive for Style/RedundantFetchBlock when using with …

…`Rails.cache`

CHANGELOG.md

@@ -13,6 +13,7 @@
 
 ### Bug fixes
 
+* [#8196](https://github.com/rubocop-hq/rubocop/issues/8196): Fix a false positive for `Style/RedundantFetchBlock` when using with `Rails.cache`. ([@fatkodima][])
 * [#8195](https://github.com/rubocop-hq/rubocop/issues/8195): Fix an error for `Style/RedundantFetchBlock` when using `#fetch` with empty block. ([@koic][])
 * [#8193](https://github.com/rubocop-hq/rubocop/issues/8193): Fix a false positive for `Style/RedundantRegexpCharacterClass` when using `[\b]`. ([@owst][])
 

lib/rubocop/cop/style/redundant_fetch_block.rb

@@ -46,8 +46,7 @@ class RedundantFetchBlock < Cop
 
         def on_block(node)
           redundant_fetch_block_candidate?(node) do |send, body|
-            return if body&.const_type? && !check_for_constant?
-            return if body&.str_type? && !check_for_string?
+            return if should_not_check?(send, body)
 
             range = fetch_range(send, node)
             good = build_good_method(send, body)
@@ -82,6 +81,16 @@ def const_type?(node)
           node&.const_type?
         end
 
+        def should_not_check?(send, body)
+          (body&.const_type? && !check_for_constant?) ||
+            (body&.str_type? && !check_for_string?) ||
+            rails_cache?(send.receiver)
+        end
+
+        def_node_matcher :rails_cache?, <<~PATTERN
+          (send (const _ :Rails) :cache)
+        PATTERN
+
         def fetch_range(send, node)
           range_between(send.loc.selector.begin_pos, node.loc.end.end_pos)
         end

spec/rubocop/cop/style/redundant_fetch_block_spec.rb

@@ -123,6 +123,12 @@
       inspect_source('hash.fetch(:key) { |k| "missing-#{k}" }')
       expect(cop.offenses.size).to eq(0)
     end
+
+    it 'does not register an offense when using `#fetch` with `Rails.cache`' do
+      expect_no_offenses(<<~RUBY)
+        Rails.cache.fetch(:key) { :value }
+      RUBY
+    end
   end
 
   context 'with SafeForConstants: false' do