[Fix #49] Fix false negatives for Rake/Desc when a task has a single prerequisite in an array.

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## master (unreleased)
 
+* [#49](https://github.com/rubocop/rubocop-rake/issues/49): Fix false negatives for `Rake/Desc` when a task has a single prerequisite in an array. ([@ydakuka][])
+
 ## 0.7.1 (2025-02-16)
 
 ### Bug fixes
@@ -78,3 +80,4 @@
 [@jaruuuu]: https://github.com/jaruuuu
 [@koic]: https://github.com/koic
 [@tejasbubane]: https://github.com/tejasbubane
+[@ydakuka]: https://github.com/ydakuka

lib/rubocop/cop/rake/desc.rb

@@ -39,10 +39,8 @@ class Desc < Base
 
         def on_task(node)
           return if task_with_desc?(node)
-          return if Helper::TaskName.task_name(node) == :default
-
-          requirements = prerequisites(node)
-          return if requirements&.array_type?
+          return if default_task?(node)
+          return if multiple_prerequisites?(node)
 
           add_offense(node)
         end
@@ -76,6 +74,18 @@ def on_task(node)
         private def can_insert_desc_to?(parent)
           parent.type?(:begin, :block, :kwbegin)
         end
+
+        private def default_task?(node)
+          Helper::TaskName.task_name(node) == :default
+        end
+
+        private def multiple_prerequisites?(node)
+          requirements = prerequisites(node)
+          return false unless requirements&.array_type?
+
+          children = requirements.children
+          children && children.size > 1
+        end
       end
     end
   end

spec/rubocop/cop/rake/desc_spec.rb

@@ -68,12 +68,28 @@
     expect_offense(<<~RUBY)
       task release: 'changelog:check_clean'
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Describe the task with `desc` method.
+
+      task release: :changelog
+      ^^^^^^^^^^^^^^^^^^^^^^^^ Describe the task with `desc` method.
+
+      task release: %w[changelog]
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Describe the task with `desc` method.
+
+      task release: %i[changelog]
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Describe the task with `desc` method.
+
+      task "release" => :environment
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Describe the task with `desc` method.
     RUBY
   end
 
   it 'does not register an offense for multiple prerequisite declarations' do
     expect_no_offenses(<<~RUBY)
       task release: ['changelog:check_clean', 'changelog:create']
+
+      task release: %w[changelog lint]
+
+      task release: %i[changelog lint]
     RUBY
   end
 end