From fb275119de364c60a800d018916ca048f29870b6 Mon Sep 17 00:00:00 2001
From: Daniel Vandersluis <daniel.vandersluis@gmail.com>
Date: Fri, 25 Sep 2020 02:40:15 -0400
Subject: [PATCH] Enable autocorrection for `Style/DateTime` (#8738)

Co-authored-by: Bozhidar Batsov <bozhidar@batsov.com>
---
 CHANGELOG.md                             |  1 +
 config/default.yml                       |  3 ++-
 docs/modules/ROOT/pages/cops_style.adoc  |  4 ++--
 lib/rubocop/cop/style/date_time.rb       | 13 ++++++++++++-
 spec/rubocop/cop/style/date_time_spec.rb | 12 ++++++++++++
 5 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0f04e919371..a53fc1330a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 ### New features
 
 * [#8790](https://github.com/rubocop-hq/rubocop/pull/8790): Add `AllowedMethods` option to `Style/OptionalBooleanParameter` cop. ([@fatkodima][])
+* [#8738](https://github.com/rubocop-hq/rubocop/issues/8738): Add autocorrection to `Style/DateTime`. ([@dvandersluis][])
 
 ### Bug fixes
 
diff --git a/config/default.yml b/config/default.yml
index 5f3adaee625..0d7b46acc3a 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -2863,7 +2863,8 @@ Style/DateTime:
   StyleGuide: '#date--time'
   Enabled: false
   VersionAdded: '0.51'
-  VersionChanged: '0.59'
+  VersionChanged: '0.92'
+  SafeAutoCorrect: false
   AllowCoercion: false
 
 Style/DefWithParentheses:
diff --git a/docs/modules/ROOT/pages/cops_style.adoc b/docs/modules/ROOT/pages/cops_style.adoc
index a668eaf9d10..e1ea36e09d0 100644
--- a/docs/modules/ROOT/pages/cops_style.adoc
+++ b/docs/modules/ROOT/pages/cops_style.adoc
@@ -1879,9 +1879,9 @@ an offense is reported.
 
 | Disabled
 | Yes
-| No
+| Yes (Unsafe)
 | 0.51
-| 0.59
+| 0.92
 |===
 
 This cop checks for consistent usage of the `DateTime` class over the
diff --git a/lib/rubocop/cop/style/date_time.rb b/lib/rubocop/cop/style/date_time.rb
index a3ff50cfa54..d7b9a6c0097 100644
--- a/lib/rubocop/cop/style/date_time.rb
+++ b/lib/rubocop/cop/style/date_time.rb
@@ -42,6 +42,8 @@ module Style
       #   # good
       #   something.to_time
       class DateTime < Base
+        extend AutoCorrector
+
         CLASS_MSG = 'Prefer Time over DateTime.'
         COERCION_MSG = 'Do not use #to_datetime.'
 
@@ -63,7 +65,10 @@ def on_send(node)
           return if historic_date?(node)
 
           message = to_datetime?(node) ? COERCION_MSG : CLASS_MSG
-          add_offense(node, message: message)
+
+          add_offense(node, message: message) do |corrector|
+            autocorrect(corrector, node)
+          end
         end
 
         private
@@ -71,6 +76,12 @@ def on_send(node)
         def disallow_coercion?
           !cop_config['AllowCoercion']
         end
+
+        def autocorrect(corrector, node)
+          return if to_datetime?(node)
+
+          corrector.replace(node.receiver.loc.name, 'Time')
+        end
       end
     end
   end
diff --git a/spec/rubocop/cop/style/date_time_spec.rb b/spec/rubocop/cop/style/date_time_spec.rb
index 02249c8f679..85dc2893eac 100644
--- a/spec/rubocop/cop/style/date_time_spec.rb
+++ b/spec/rubocop/cop/style/date_time_spec.rb
@@ -8,6 +8,10 @@
       DateTime.now
       ^^^^^^^^^^^^ Prefer Time over DateTime.
     RUBY
+
+    expect_correction(<<~RUBY)
+      Time.now
+    RUBY
   end
 
   it 'registers an offense when using ::DateTime for current time' do
@@ -15,6 +19,10 @@
       ::DateTime.now
       ^^^^^^^^^^^^^^ Prefer Time over DateTime.
     RUBY
+
+    expect_correction(<<~RUBY)
+      ::Time.now
+    RUBY
   end
 
   it 'registers an offense when using DateTime for modern date' do
@@ -22,6 +30,10 @@
       DateTime.iso8601('2016-06-29')
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Prefer Time over DateTime.
     RUBY
+
+    expect_correction(<<~RUBY)
+      Time.iso8601('2016-06-29')
+    RUBY
   end
 
   it 'does not register an offense when using Time for current time' do