Fix OverwritingSetup raising an error for unnamed subject

Darhazer · Darhazer · commit b32950be7b79 · 2018-05-28T01:02:49.000+03:00
diff --git a/lib/rubocop/cop/rspec/overwriting_setup.rb b/lib/rubocop/cop/rspec/overwriting_setup.rb
@@ -45,10 +45,15 @@ def on_block(node)
         def find_duplicates(node)
           setup_expressions = Set.new
           node.each_child_node do |child|
-            setup?(child) do
-              name = one(child.send_node.arguments).value
-              yield child, name unless setup_expressions.add?(name)
-            end
+            next unless setup?(child)
+
+            name = if child.send_node.arguments?
+                     child.send_node.first_argument.value
+                   else
+                     :subject
+                   end
+
+            yield child, name unless setup_expressions.add?(name)
           end
         end
       end
diff --git a/spec/rubocop/cop/rspec/overwriting_setup_spec.rb b/spec/rubocop/cop/rspec/overwriting_setup_spec.rb
@@ -22,6 +22,17 @@
     RUBY
   end
 
+  it 'works with `subject!` and `let!`' do
+    expect_offense(<<-RUBY)
+      RSpec.describe User do
+        subject!(:a) { a }
+
+        let!(:a) { b }
+        ^^^^^^^^^^^^^^ `a` is already defined.
+      end
+    RUBY
+  end
+
   it 'finds `let!` overwriting `let`' do
     expect_offense(<<-RUBY)
       RSpec.describe User do
@@ -44,6 +55,17 @@
     RUBY
   end
 
+  it 'handles unnamed subjects' do
+    expect_offense(<<-RUBY)
+      RSpec.describe User do
+        subject { a }
+
+        let(:subject) { b }
+        ^^^^^^^^^^^^^^^^^^^ `subject` is already defined.
+      end
+    RUBY
+  end
+
   it 'does not encounter an error when handling an empty describe' do
     expect { inspect_source('RSpec.describe(User) do end', 'a_spec.rb') }
       .not_to raise_error
