Add autocorrect to Rails/RakeEnvironment cop

Closes rubocop#211

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### New features
 
 * [#51](https://github.com/rubocop-hq/rubocop-rails/issues/51): Add allowed receiver class names option for `Rails/DynamicFindBy`. ([@tejasbubane][])
+* [#211](https://github.com/rubocop-hq/rubocop-rails/issues/211): Add autocorrect to `Rails/RakeEnvironment` cop. ([@tejasbubane][])
 
 ### Bug fixes
 

config/default.yml

@@ -367,6 +367,7 @@ Rails/RakeEnvironment:
   Enabled: true
   Safe: false
   VersionAdded: '2.4'
+  VersionChanged: '2.6'
   Include:
     - '**/Rakefile'
     - '**/*.rake'

lib/rubocop/cop/rails/rake_environment.rb

@@ -41,8 +41,25 @@ def on_block(node)
           end
         end
 
+        def autocorrect(node)
+          lambda do |corrector|
+            task_name = node.arguments[0]
+            task_dependency = correct_task_dependency(task_name)
+
+            corrector.replace(task_name.loc.expression, task_dependency)
+          end
+        end
+
         private
 
+        def correct_task_dependency(task_name)
+          if task_name.sym_type?
+            task_name.source.delete(':|\'|"') + ': :environment'
+          else
+            "#{task_name.source} => :environment"
+          end
+        end
+
         def task_name(node)
           first_arg = node.arguments[0]
           case first_arg&.type

manual/cops_rails.md

@@ -1722,7 +1722,7 @@ UnlessBlank | `true` | Boolean
 
 Enabled by default | Safe | Supports autocorrection | VersionAdded | VersionChanged
 --- | --- | --- | --- | ---
-Enabled | No | No | 2.4 | -
+Enabled | No | Yes  | 2.4 | 2.6
 
 This cop checks for Rake tasks without the `:environment` task
 dependency. The `:environment` task loads application code for other

spec/rubocop/cop/rails/rake_environment_spec.rb

@@ -11,6 +11,37 @@
       ^^^^^^^^^ Include `:environment` task as a dependency for all Rake tasks.
       end
     RUBY
+
+    expect_correction(<<~RUBY)
+      task foo: :environment do
+      end
+    RUBY
+  end
+
+  it 'registers an offense for string task name' do
+    expect_offense(<<~RUBY)
+      task 'bar' do
+      ^^^^^^^^^^ Include `:environment` task as a dependency for all Rake tasks.
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      task 'bar' => :environment do
+      end
+    RUBY
+  end
+
+  it 'registers an offense for namespaced task name' do
+    expect_offense(<<~RUBY)
+      task 'foo:bar:baz' do
+      ^^^^^^^^^^^^^^^^^^ Include `:environment` task as a dependency for all Rake tasks.
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      task 'foo:bar:baz' => :environment do
+      end
+    RUBY
   end
 
   it 'does not register an offense to task with :environment ' \
@@ -89,4 +120,10 @@
       task(:foo).do_something
     RUBY
   end
+
+  it 'does not register an offense to task with string name and arguments' do
+    expect_no_offenses(<<~RUBY)
+      task 'foo' => [dep, :bar]
+    RUBY
+  end
 end