[Fix rubocop#12271] Fix a false positive for `Lint/RedundantSafeNavig…

…ation` Fixes rubocop#12271. This PR fixes a false positive for `Lint/RedundantSafeNavigation` when using snake case constant receiver. Camel case is used for naming classes and modules, while snake case is used for all other constants. This naming conforms with `Naming/ConstantName` cop. Since constants that turn into classes or modules are normally not `nil`, they will continue to be detected. However, this PR will update to allow safe navigation for constants in snake case. This change resolves both issue rubocop/rubocop-rails#1104 and rubocop#12271.
koic · Oct 13, 2023 · 2c1ee21 · 2c1ee21
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diff --git a/changelog/fix_a_false_positive_for_lint_redundant_safe_navigation.md b/changelog/fix_a_false_positive_for_lint_redundant_safe_navigation.md
@@ -0,0 +1 @@
+* [#12271](https://github.com/rubocop/rubocop/issues/12271): Fix a false positive for `Lint/RedundantSafeNavigation` when using snake case constant receiver. ([@koic][])
diff --git a/lib/rubocop/cop/lint/redundant_safe_navigation.rb b/lib/rubocop/cop/lint/redundant_safe_navigation.rb
@@ -4,8 +4,8 @@ module RuboCop
   module Cop
     module Lint
       # Checks for redundant safe navigation calls.
-      # Use cases where a constant is `nil` are rare and an offense is detected
-      # when the receiver is a constant.
+      # Use cases where a constant, named in camel case for classes and modules is `nil` are rare,
+      # and an offense is not detected when the receiver is a snake case constant.
       #
       # For all receivers, the `instance_of?`, `kind_of?`, `is_a?`, `eql?`, `respond_to?`,
       # and `equal?` methods are checked by default.
@@ -26,7 +26,7 @@ module Lint
       #
       # @example
       #   # bad
-      #   Const&.do_something
+      #   CamelCaseConst&.do_something
       #
       #   # bad
       #   do_something if attrs&.respond_to?(:[])
@@ -40,7 +40,7 @@ module Lint
       #   end
       #
       #   # good
-      #   Const.do_something
+      #   CamelCaseConst.do_something
       #
       #   # good
       #   while node.is_a?(BeginNode)
@@ -67,20 +67,24 @@ class RedundantSafeNavigation < Base
 
         NIL_SPECIFIC_METHODS = (nil.methods - Object.new.methods).to_set.freeze
 
+        SNAKE_CASE = /\A[[:digit:][:upper:]_]+\z/.freeze
+
         # @!method respond_to_nil_specific_method?(node)
         def_node_matcher :respond_to_nil_specific_method?, <<~PATTERN
           (csend _ :respond_to? (sym %NIL_SPECIFIC_METHODS))
         PATTERN
 
+        # rubocop:disable Metrics/AbcSize
         def on_csend(node)
-          unless node.receiver.const_type?
+          unless node.receiver.const_type? && !node.receiver.source.match?(SNAKE_CASE)
             return unless check?(node) && allowed_method?(node.method_name)
             return if respond_to_nil_specific_method?(node)
           end
 
           range = range_between(node.loc.dot.begin_pos, node.source_range.end_pos)
           add_offense(range) { |corrector| corrector.replace(node.loc.dot, '.') }
         end
+        # rubocop:enable Metrics/AbcSize
 
         private
 

diff --git a/spec/rubocop/cop/lint/redundant_safe_navigation_spec.rb b/spec/rubocop/cop/lint/redundant_safe_navigation_spec.rb
@@ -3,14 +3,27 @@
 RSpec.describe RuboCop::Cop::Lint::RedundantSafeNavigation, :config do
   let(:cop_config) { { 'AllowedMethods' => %w[respond_to?] } }
 
-  it 'registers an offense and corrects when `&.` is used for const receiver' do
+  it 'registers an offense and corrects when `&.` is used for camel case const receiver' do
     expect_offense(<<~RUBY)
-      Foo&.do_something
-         ^^^^^^^^^^^^^^ Redundant safe navigation detected.
+      Const&.do_something
+           ^^^^^^^^^^^^^^ Redundant safe navigation detected.
+      ConstName&.do_something
+               ^^^^^^^^^^^^^^ Redundant safe navigation detected.
+      Const_name&.do_something # It is treated as camel case, similar to the `Naming/ConstantName` cop.
+                ^^^^^^^^^^^^^^ Redundant safe navigation detected.
     RUBY
 
     expect_correction(<<~RUBY)
-      Foo.do_something
+      Const.do_something
+      ConstName.do_something
+      Const_name.do_something # It is treated as camel case, similar to the `Naming/ConstantName` cop.
+    RUBY
+  end
+
+  it 'does not register an offense and corrects when `&.` is used for snake case const receiver' do
+    expect_no_offenses(<<~RUBY)
+      CONST&.do_something
+      CONST_NAME&.do_something
     RUBY
   end