[Fix #11219] Make Style/SelectByRegexp aware of !~ method

Fixes #11219.

This PR makes `Style/SelectByRegexp` aware of `!~` method.

changelog/new_make_style_select_by_regexp_aware_of_doesnt_match.md

@@ -0,0 +1 @@
+* [#11219](https://github.com/rubocop/rubocop/issues/11219): Make `Style/SelectByRegexp` aware of `!~` method. ([@koic][])

lib/rubocop/cop/style/select_by_regexp.rb

@@ -49,7 +49,8 @@ class SelectByRegexp < Base
         MSG = 'Prefer `%<replacement>s` to `%<original_method>s` with a regexp match.'
         RESTRICT_ON_SEND = %i[select find_all reject].freeze
         REPLACEMENTS = { select: 'grep', find_all: 'grep', reject: 'grep_v' }.freeze
-        REGEXP_METHODS = %i[match? =~].to_set.freeze
+        OPPOSITE_REPLACEMENTS = { select: 'grep_v', find_all: 'grep_v', reject: 'grep' }.freeze
+        REGEXP_METHODS = %i[match? =~ !~].to_set.freeze
 
         # @!method regexp_match?(node)
         def_node_matcher :regexp_match?, <<~PATTERN
@@ -90,8 +91,10 @@ def on_send(node)
           return unless (regexp_method_send_node = extract_send_node(block_node))
           return if match_predicate_without_receiver?(regexp_method_send_node)
 
+          opposite = regexp_method_send_node.send_type? && regexp_method_send_node.method?(:!~)
           regexp = find_regexp(regexp_method_send_node, block_node)
-          register_offense(node, block_node, regexp)
+
+          register_offense(node, block_node, regexp, opposite)
         end
 
         private
@@ -102,8 +105,9 @@ def receiver_allowed?(node)
           node.hash_type? || creates_hash?(node) || env_const?(node)
         end
 
-        def register_offense(node, block_node, regexp)
-          replacement = REPLACEMENTS[node.method_name.to_sym]
+        def register_offense(node, block_node, regexp, opposite)
+          method_name = node.method_name.to_sym
+          replacement = opposite ? OPPOSITE_REPLACEMENTS[method_name] : REPLACEMENTS[method_name]
           message = format(MSG, replacement: replacement, original_method: node.method_name)
 
           add_offense(block_node, message: message) do |corrector|

spec/rubocop/cop/style/select_by_regexp_spec.rb

@@ -321,4 +321,105 @@
       end
     end
   end
+
+  { 'select' => 'grep_v', 'find_all' => 'grep_v', 'reject' => 'grep' }.each do |method, correction|
+    message = "Prefer `#{correction}` to `#{method}` with a regexp match."
+
+    context "with #{method}" do
+      it 'registers an offense and corrects for `blockvar !~ regexp`' do
+        expect_offense(<<~RUBY, method: method)
+          array.#{method} { |x| x !~ /regexp/ }
+          ^^^^^^^{method}^^^^^^^^^^^^^^^^^^^^^^ #{message}
+        RUBY
+
+        expect_correction(<<~RUBY)
+          array.#{correction}(/regexp/)
+        RUBY
+      end
+
+      it 'registers an offense and corrects for `blockvar !~ lvar`' do
+        expect_offense(<<~RUBY, method: method)
+          lvar = /regexp/
+          array.#{method} { |x| x !~ lvar }
+          ^^^^^^^{method}^^^^^^^^^^^^^^^^^^ #{message}
+        RUBY
+
+        expect_correction(<<~RUBY)
+          lvar = /regexp/
+          array.#{correction}(lvar)
+        RUBY
+      end
+
+      it 'registers an offense and corrects for `regexp !~ blockvar`' do
+        expect_offense(<<~RUBY, method: method)
+          array.#{method} { |x| /regexp/ !~ x }
+          ^^^^^^^{method}^^^^^^^^^^^^^^^^^^^^^^ #{message}
+        RUBY
+
+        expect_correction(<<~RUBY)
+          array.#{correction}(/regexp/)
+        RUBY
+      end
+
+      it 'registers an offense and corrects for `lvar !~ blockvar`' do
+        expect_offense(<<~RUBY, method: method)
+          lvar = /regexp/
+          array.#{method} { |x| lvar !~ x }
+          ^^^^^^^{method}^^^^^^^^^^^^^^^^^^ #{message}
+        RUBY
+
+        expect_correction(<<~RUBY)
+          lvar = /regexp/
+          array.#{correction}(lvar)
+        RUBY
+      end
+
+      it 'registers an offense and corrects when there is no explicit regexp' do
+        expect_offense(<<~RUBY, method: method)
+          array.#{method} { |x| x !~ y }
+          ^^^^^^^{method}^^^^^^^^^^^^^^^ #{message}
+          array.#{method} { |x| x !~ REGEXP }
+          ^^^^^^^{method}^^^^^^^^^^^^^^^^^^^^ #{message}
+          array.#{method} { |x| x !~ foo.bar.baz(quux) }
+          ^^^^^^^{method}^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ #{message}
+        RUBY
+
+        expect_correction(<<~RUBY)
+          array.#{correction}(y)
+          array.#{correction}(REGEXP)
+          array.#{correction}(foo.bar.baz(quux))
+        RUBY
+      end
+
+      context 'with `numblock`s', :ruby27 do
+        it 'registers an offense and corrects for `blockvar !~ regexp`' do
+          expect_offense(<<~RUBY, method: method)
+            array.#{method} { _1 !~ /regexp/ }
+            ^^^^^^^{method}^^^^^^^^^^^^^^^^^^^ #{message}
+          RUBY
+
+          expect_correction(<<~RUBY)
+            array.#{correction}(/regexp/)
+          RUBY
+        end
+
+        it 'registers an offense and corrects for `regexp !~ blockvar`' do
+          expect_offense(<<~RUBY, method: method)
+            array.#{method} { /regexp/ !~ _1 }
+            ^^^^^^^{method}^^^^^^^^^^^^^^^^^^^ #{message}
+          RUBY
+
+          expect_correction(<<~RUBY)
+            array.#{correction}(/regexp/)
+          RUBY
+        end
+
+        it 'does not register an offense if there is more than one numbered param' do
+          expect_no_offenses(<<~RUBY)
+            array.#{method} { _1 !~ _2 }
+          RUBY
+        end
+      end
+    end
+  end
 end