Recover Ruby 2.2 code analysis using TargetRubyVersion: 2.2

Follow up rubocop#10632 (comment).

Reverts part of rubocop#6766, rubocop#7026, and rubocop#7030.

Only the Ruby version (2.2) to runtime should have been dropped, not code analysis.
This PR makes Ruby 2.2 code analysis with `TargetRubyVersion: 2.2`.
It aims to solve essentially the same problem as rubocop#10626, rubocop#10632, and rubocop#10640.

Previously, there was the following default enforced style `when_needed` for
`Style/FrozenStringLiteralComment` cop.

```ruby
# @example EnforcedStyle: when_needed (default)
#   # The `when_needed` style will add the frozen string literal
#   # to files only when the `TargetRubyVersion` is set to 2.3+.
#   # bad
#   module Foo
#     # ...
#   end
#
#   # good
#   # frozen_string_literal: true
#
#   module Foo
#     # ...
#   end
```

This PR does not restore that option, but sets the `minimum_target_ruby_version 2.3`
to make `always (default)` apply by default. It is a simple solution that does not
handle frozen literal magic comment added in Ruby 2.3 when `TargetRubyVersion` is
Ruby 2.2 or lower.

changelog/changelog/fix_recover_ruby_22_code_analysis.md

@@ -0,0 +1 @@
+* [#10644](https://github.com/rubocop/rubocop/pull/10644): Recover Ruby 2.2 code analysis using `TargetRubyVersion: 2.2`. ([@koic][])

lib/rubocop/cop/lint/safe_navigation_chain.rb

@@ -25,6 +25,9 @@ module Lint
       #   x&.foo || bar
       class SafeNavigationChain < Base
         include NilMethods
+        extend TargetRubyVersion
+
+        minimum_target_ruby_version 2.3
 
         MSG = 'Do not chain ordinary method call after safe navigation operator.'
 

lib/rubocop/cop/style/frozen_string_literal_comment.rb

@@ -8,7 +8,7 @@ module Style
       # It will add the `# frozen_string_literal: true` magic comment to the top
       # of files to enable frozen string literals. Frozen string literals may be
       # default in future Ruby. The comment will be added below a shebang and
-      # encoding comment.
+      # encoding comment. The frozen string literal comment is only valid in Ruby 2.3+.
       #
       # Note that the cop will accept files where the comment exists but is set
       # to `false` instead of `true`.
@@ -86,6 +86,9 @@ class FrozenStringLiteralComment < Base
         include FrozenStringLiteral
         include RangeHelp
         extend AutoCorrector
+        extend TargetRubyVersion
+
+        minimum_target_ruby_version 2.3
 
         MSG_MISSING_TRUE = 'Missing magic comment `# frozen_string_literal: true`.'
         MSG_MISSING = 'Missing frozen string literal comment.'

lib/rubocop/cop/style/numeric_predicate.rb

@@ -82,7 +82,7 @@ def check(node)
               predicate(node)
             end
 
-          return unless numeric && operator
+          return unless numeric && operator && replacement_supported?(operator)
 
           [numeric, replacement(numeric, operator)]
         end
@@ -107,6 +107,14 @@ def require_parentheses?(node)
           node.send_type? && node.binary_operation? && !node.parenthesized?
         end
 
+        def replacement_supported?(operator)
+          if %i[> <].include?(operator)
+            target_ruby_version >= 2.3
+          else
+            true
+          end
+        end
+
         def invert
           lambda do |comparison, numeric|
             comparison = { :> => :<, :< => :> }[comparison] || comparison

lib/rubocop/cop/util.rb

@@ -159,7 +159,7 @@ def to_supported_styles(enforced_style)
       private
 
       def compatible_external_encoding_for?(src)
-        src = src.dup if RUBY_ENGINE == 'jruby'
+        src = src.dup if RUBY_VERSION < '2.3' || RUBY_ENGINE == 'jruby'
         src.force_encoding(Encoding.default_external).valid_encoding?
       end
     end

lib/rubocop/rspec/shared_contexts.rb

@@ -116,6 +116,10 @@ def source_range(range, buffer: source_buffer)
   end
 end
 
+RSpec.shared_context 'ruby 2.2', :ruby22 do
+  let(:ruby_version) { 2.2 }
+end
+
 RSpec.shared_context 'ruby 2.3', :ruby23 do
   let(:ruby_version) { 2.3 }
 end

lib/rubocop/target_ruby.rb

@@ -4,7 +4,7 @@ module RuboCop
   # The kind of Ruby that code inspected by RuboCop is written in.
   # @api private
   class TargetRuby
-    KNOWN_RUBIES = [2.3, 2.4, 2.5, 2.6, 2.7, 3.0, 3.1, 3.2].freeze
+    KNOWN_RUBIES = [2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 3.0, 3.1, 3.2].freeze
     DEFAULT_VERSION = 2.6
 
     OBSOLETE_RUBIES = {

spec/rubocop/cli_spec.rb

@@ -1724,7 +1724,7 @@ def method(foo, bar, qux, fred, arg5, f) end #{'#' * 85}
           'Error: RuboCop found unknown Ruby version 4.0 in `TargetRubyVersion`'
         )
         expect($stderr.string.strip).to match(
-          /Supported versions: 2.3, 2.4, 2.5, 2.6, 2.7, 3.0, 3.1, 3.2/
+          /Supported versions: 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 3.0, 3.1, 3.2/
         )
       end
     end
@@ -1746,7 +1746,7 @@ def method(foo, bar, qux, fred, arg5, f) end #{'#' * 85}
           /2\.0-compatible analysis was dropped after version 0\.50/
         )
 
-        expect($stderr.string.strip).to match(/Supported versions: 2.3/)
+        expect($stderr.string.strip).to match(/Supported versions: 2.2/)
       end
     end
   end

spec/rubocop/config_loader_spec.rb

@@ -1188,7 +1188,7 @@ class Loop < Base
       end
 
       context 'when the specified version is obsolete' do
-        let(:inherited_version) { '2.2' }
+        let(:inherited_version) { '2.1' }
 
         context 'and it is not overridden' do
           before do
@@ -1199,7 +1199,7 @@ class Loop < Base
 
           it 'raises a validation error' do
             expect { configuration_from_file }.to raise_error(RuboCop::ValidationError) do |error|
-              expect(error.message).to start_with('RuboCop found unsupported Ruby version 2.2')
+              expect(error.message).to start_with('RuboCop found unsupported Ruby version 2.1')
             end
           end
         end