Merge pull request rubocop#12539 from koic/fix_false_positives_for_li…

…nt_literal_assignment_in_condition

Fix false positives for `Lint/LiteralAssignmentInCondition`

changelog/fix_false_positives_for_lint_literal_assignment_in_condition.md

@@ -0,0 +1 @@
+* [#12539](https://github.com/rubocop/rubocop/pull/12539): Fix false positives for `Lint/LiteralAssignmentInCondition` when a collection literal contains non-literal elements. ([@koic][])

lib/rubocop/cop/lint/literal_assignment_in_condition.rb

@@ -41,7 +41,7 @@ def on_if(node)
             next unless asgn_node.loc.operator
 
             rhs = asgn_node.to_a.last
-            next if !forbidden_literal?(rhs) || parallel_assignment_with_splat_operator?(rhs)
+            next if !all_literals?(rhs) || parallel_assignment_with_splat_operator?(rhs)
 
             range = offense_range(asgn_node, rhs)
 
@@ -59,10 +59,17 @@ def traverse_node(node, &block)
           node.each_child_node { |child| traverse_node(child, &block) }
         end
 
-        def forbidden_literal?(node)
-          return false if node.dstr_type? || node.xstr_type?
-
-          node.respond_to?(:literal?) && node.literal?
+        def all_literals?(node)
+          case node.type
+          when :dstr, :xstr
+            false
+          when :array
+            node.values.all? { |value| all_literals?(value) }
+          when :hash
+            (node.values + node.keys).all? { |item| all_literals?(item) }
+          else
+            node.respond_to?(:literal?) && node.literal?
+          end
         end
 
         def parallel_assignment_with_splat_operator?(node)

spec/rubocop/cop/lint/literal_assignment_in_condition_spec.rb

@@ -31,14 +31,59 @@
     RUBY
   end
 
-  it 'registers an offense when assigning array literal to local variable in `if` condition' do
+  it 'registers an offense when assigning empty array literal to local variable in `if` condition' do
     expect_offense(<<~RUBY)
       if test = []
               ^^^^ Don't use literal assignment `= []` in conditional, should be `==` or non-literal operand.
       end
     RUBY
   end
 
+  it 'registers an offense when assigning array literal with only literal elements to local variable in `if` condition' do
+    expect_offense(<<~RUBY)
+      if test = [1, 2, 3]
+              ^^^^^^^^^^^ Don't use literal assignment `= [1, 2, 3]` in conditional, should be `==` or non-literal operand.
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when assigning array literal with non-literal elements to local variable in `if` condition' do
+    expect_no_offenses(<<~RUBY)
+      if test = [42, x, y]
+      end
+    RUBY
+  end
+
+  it 'registers an offense when assigning empty hash literal to local variable in `if` condition' do
+    expect_offense(<<~RUBY)
+      if test = {}
+              ^^^^ Don't use literal assignment `= {}` in conditional, should be `==` or non-literal operand.
+      end
+    RUBY
+  end
+
+  it 'registers an offense when assigning hash literal with only literal elements to local variable in `if` condition' do
+    expect_offense(<<~RUBY)
+      if test = {x: :y}
+              ^^^^^^^^^ Don't use literal assignment `= {x: :y}` in conditional, should be `==` or non-literal operand.
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when assigning hash literal with non-literal key to local variable in `if` condition' do
+    expect_no_offenses(<<~RUBY)
+      if test = {x => :y}
+      end
+    RUBY
+  end
+
+  it 'does not register an offense when assigning hash literal with non-literal value to local variable in `if` condition' do
+    expect_no_offenses(<<~RUBY)
+      if test = {x: y}
+      end
+    RUBY
+  end
+
   it 'does not register an offense when assigning non-literal to local variable in `if` condition' do
     expect_no_offenses(<<~RUBY)
       if test = do_something