Add <> operator to Rails/WhereNot cop.

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Bug fixes
 
 * [#345](https://github.com/rubocop-hq/rubocop-rails/issues/345): Fix error of `Rails/AfterCommitOverride` on `after_commit` with a lambda. ([@pocke][])
+* [#351](https://github.com/rubocop-hq/rubocop-rails/pull/351): Add `<>` operator to `Rails/WhereNot` cop. ([@Tietew][])
 
 ## 2.8.0 (2020-09-04)
 
@@ -281,3 +282,4 @@
 [@mobilutz]: https://github.com/mobilutz
 [@bubaflub]: https://github.com/bubaflub
 [@dvandersluis]: https://github.com/dvandersluis
+[@Tietew]: https://github.com/Tietew

docs/modules/ROOT/pages/cops_rails.adoc

@@ -4372,6 +4372,8 @@ in `where` can be replaced with `where.not(...)`.
 # bad
 User.where('name != ?', 'Gabe')
 User.where('name != :name', name: 'Gabe')
+User.where('name <> ?', 'Gabe')
+User.where('name <> :name', name: 'Gabe')
 User.where('name IS NOT NULL')
 User.where('name NOT IN (?)', ['john', 'jane'])
 User.where('name NOT IN (:names)', names: ['john', 'jane'])

lib/rubocop/cop/rails/where_not.rb

@@ -10,6 +10,8 @@ module Rails
       #   # bad
       #   User.where('name != ?', 'Gabe')
       #   User.where('name != :name', name: 'Gabe')
+      #   User.where('name <> ?', 'Gabe')
+      #   User.where('name <> :name', name: 'Gabe')
       #   User.where('name IS NOT NULL')
       #   User.where('name NOT IN (?)', ['john', 'jane'])
       #   User.where('name NOT IN (:names)', names: ['john', 'jane'])
@@ -62,9 +64,9 @@ def autocorrect(node)
           end
         end
 
-        NOT_EQ_ANONYMOUS_RE = /\A([\w.]+)\s+!=\s+\?\z/.freeze                  # column != ?
+        NOT_EQ_ANONYMOUS_RE = /\A([\w.]+)\s+(?:!=|<>)\s+\?\z/.freeze           # column != ?, column <> ?
         NOT_IN_ANONYMOUS_RE = /\A([\w.]+)\s+NOT\s+IN\s+\(\?\)\z/i.freeze       # column NOT IN (?)
-        NOT_EQ_NAMED_RE     = /\A([\w.]+)\s+!=\s+:(\w+)\z/.freeze              # column != :column
+        NOT_EQ_NAMED_RE     = /\A([\w.]+)\s+(?:!=|<>)\s+:(\w+)\z/.freeze       # column != :column, column <> :column
         NOT_IN_NAMED_RE     = /\A([\w.]+)\s+NOT\s+IN\s+\(:(\w+)\)\z/i.freeze   # column NOT IN (:column)
         IS_NOT_NULL_RE      = /\A([\w.]+)\s+IS\s+NOT\s+NULL\z/i.freeze         # column IS NOT NULL
 

spec/rubocop/cop/rails/where_not_spec.rb

@@ -25,6 +25,28 @@
     RUBY
   end
 
+  it 'registers an offense and corrects when using `<>` and anonymous placeholder' do
+    expect_offense(<<~RUBY)
+      User.where('name <> ?', 'Gabe')
+           ^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `where.not(name: 'Gabe')` instead of manually constructing negated SQL in `where`.
+    RUBY
+
+    expect_correction(<<~RUBY)
+      User.where.not(name: 'Gabe')
+    RUBY
+  end
+
+  it 'registers an offense and corrects when using `<>` and named placeholder' do
+    expect_offense(<<~RUBY)
+      User.where('name <> :name', name: 'Gabe')
+           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `where.not(name: 'Gabe')` instead of manually constructing negated SQL in `where`.
+    RUBY
+
+    expect_correction(<<~RUBY)
+      User.where.not(name: 'Gabe')
+    RUBY
+  end
+
   it 'registers an offense and corrects when using `IS NOT NULL`' do
     expect_offense(<<~RUBY)
       User.where('name IS NOT NULL')
@@ -58,7 +80,7 @@
     RUBY
   end
 
-  it 'registers an offense and corrects when using namespaced columns' do
+  it 'registers an offense and corrects when using `!=` and namespaced columns' do
     expect_offense(<<~RUBY)
       Course.where('enrollments.student_id != ?', student.id)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `where.not('enrollments.student_id' => student.id)` instead of manually constructing negated SQL in `where`.
@@ -69,6 +91,17 @@
     RUBY
   end
 
+  it 'registers an offense and corrects when using `<>` and namespaced columns' do
+    expect_offense(<<~RUBY)
+      Course.where('enrollments.student_id <> ?', student.id)
+             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `where.not('enrollments.student_id' => student.id)` instead of manually constructing negated SQL in `where`.
+    RUBY
+
+    expect_correction(<<~RUBY)
+      Course.where.not('enrollments.student_id' => student.id)
+    RUBY
+  end
+
   context 'with array arguments' do
     it 'registers an offense and corrects when using `!=` and anonymous placeholder' do
       expect_offense(<<~RUBY)
@@ -92,6 +125,28 @@
       RUBY
     end
 
+    it 'registers an offense and corrects when using `<>` and anonymous placeholder' do
+      expect_offense(<<~RUBY)
+        User.where(['name <> ?', 'Gabe'])
+             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `where.not(name: 'Gabe')` instead of manually constructing negated SQL in `where`.
+      RUBY
+
+      expect_correction(<<~RUBY)
+        User.where.not(name: 'Gabe')
+      RUBY
+    end
+
+    it 'registers an offense and corrects when using `<>` and named placeholder' do
+      expect_offense(<<~RUBY)
+        User.where(['name <> :name', { name: 'Gabe' }])
+             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `where.not(name: 'Gabe')` instead of manually constructing negated SQL in `where`.
+      RUBY
+
+      expect_correction(<<~RUBY)
+        User.where.not(name: 'Gabe')
+      RUBY
+    end
+
     it 'registers an offense and corrects when using `IS NOT NULL`' do
       expect_offense(<<~RUBY)
         User.where(['name IS NOT NULL'])
@@ -125,7 +180,7 @@
       RUBY
     end
 
-    it 'registers an offense and corrects when using namespaced columns' do
+    it 'registers an offense and corrects when using `!=` and namespaced columns' do
       expect_offense(<<~RUBY)
         Course.where(['enrollments.student_id != ?', student.id])
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `where.not('enrollments.student_id' => student.id)` instead of manually constructing negated SQL in `where`.
@@ -135,6 +190,17 @@
         Course.where.not('enrollments.student_id' => student.id)
       RUBY
     end
+
+    it 'registers an offense and corrects when using `<>` and namespaced columns' do
+      expect_offense(<<~RUBY)
+        Course.where(['enrollments.student_id <> ?', student.id])
+               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Use `where.not('enrollments.student_id' => student.id)` instead of manually constructing negated SQL in `where`.
+      RUBY
+
+      expect_correction(<<~RUBY)
+        Course.where.not('enrollments.student_id' => student.id)
+      RUBY
+    end
   end
 
   it 'does not register an offense when using `where.not`' do
@@ -155,9 +221,15 @@
     RUBY
   end
 
-  it 'does not register an offense when template string contains negation and additional boolean logic' do
+  it 'does not register an offense when template string contains `!=` and additional boolean logic' do
     expect_no_offenses(<<~RUBY)
       User.where('name != ? AND age != ?', 'john', 19)
     RUBY
   end
+
+  it 'does not register an offense when template string contains `<>` and additional boolean logic' do
+    expect_no_offenses(<<~RUBY)
+      User.where('name <> ? AND age <> ?', 'john', 19)
+    RUBY
+  end
 end