Improve an offense message for RSpec/RepeatedExamplecop

Fixes: #1932

Author: ydah

CHANGELOG.md

@@ -7,6 +7,7 @@
 - Fix a false positive for `RSpec/LetSetup` when `let!` used in outer scope. ([@ydah])
 - Fix a false positive for `RSpec/ReceiveNever` cop when `allow(...).to receive(...).never`. ([@ydah])
 - Fix detection of nameless doubles with methods in `RSpec/VerifiedDoubles`. ([@ushi-as])
+- Improve an offense message for `RSpec/RepeatedExample` cop. ([@ydah])
 
 ## 3.7.0 (2025-09-01)
 

lib/rubocop/cop/rspec/repeated_example.rb

@@ -16,36 +16,55 @@ module RSpec
       #   end
       #
       class RepeatedExample < Base
-        MSG = "Don't repeat examples within an example group."
+        MSG = "Don't repeat examples within an example group. " \
+              'Repeated on line(s) %<lines>s.'
 
         def on_block(node) # rubocop:disable InternalAffairs/NumblockHandler
           return unless example_group?(node)
 
-          repeated_examples(node).each do |repeated_example|
-            add_offense(repeated_example)
+          find_repeated_examples(node).each do |repeated_examples|
+            add_offenses_for_repeated_group(repeated_examples)
           end
         end
 
         private
 
-        def repeated_examples(node)
-          RuboCop::RSpec::ExampleGroup.new(node)
-            .examples
-            .group_by { |example| example_signature(example) }
+        def find_repeated_examples(node)
+          examples = RuboCop::RSpec::ExampleGroup.new(node).examples
+
+          examples
+            .group_by { |example| build_example_signature(example) }
             .values
-            .reject(&:one?)
-            .flatten
-            .map(&:to_node)
+            .select { |group| group.size > 1 }
         end
 
-        def example_signature(example)
-          key_parts = [example.metadata, example.implementation]
-
+        def build_example_signature(example)
+          signature = [example.metadata, example.implementation]
           if example.definition.method?(:its)
-            key_parts << example.definition.arguments
+            signature << example.definition.arguments
+          end
+          signature
+        end
+
+        def add_offenses_for_repeated_group(repeated_examples)
+          repeated_examples.each do |example|
+            other_lines = extract_other_lines(repeated_examples, example)
+            add_offense(example.to_node, message: message(other_lines))
           end
+        end
+
+        def extract_other_lines(examples_group, current_example)
+          current_node = current_example.to_node
+
+          examples_group
+            .reject { |ex| ex.to_node.equal?(current_node) }
+            .map { |ex| ex.to_node.first_line }
+            .uniq
+            .sort
+        end
 
-          key_parts
+        def message(other_lines)
+          format(MSG, lines: other_lines.join(', '))
         end
       end
     end

spec/rubocop/cop/rspec/repeated_example_spec.rb

@@ -5,12 +5,12 @@
     expect_offense(<<~RUBY)
       describe 'doing x' do
         it "does x" do
-        ^^^^^^^^^^^^^^ Don't repeat examples within an example group.
+        ^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 6.
           expect(foo).to be(bar)
         end
 
         it "does y" do
-        ^^^^^^^^^^^^^^ Don't repeat examples within an example group.
+        ^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2.
           expect(foo).to be(bar)
         end
       end
@@ -49,9 +49,9 @@
     expect_offense(<<~RUBY)
       describe 'doing x' do
         its(:x) { is_expected.to be_present }
-        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group.
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 3.
         its(:x) { is_expected.to be_present }
-        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group.
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2.
       end
     RUBY
   end
@@ -89,4 +89,165 @@
       end
     RUBY
   end
+
+  it 'shows all duplicate line numbers when there are three duplicates' do
+    expect_offense(<<~RUBY)
+      describe 'doing x' do
+        it "does x" do
+        ^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 6, 10.
+          expect(foo).to be(bar)
+        end
+
+        it "does y" do
+        ^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2, 10.
+          expect(foo).to be(bar)
+        end
+
+        it "does z" do
+        ^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2, 6.
+          expect(foo).to be(bar)
+        end
+      end
+    RUBY
+  end
+
+  it 'shows all duplicate line numbers when there are four duplicates' do
+    expect_offense(<<~RUBY)
+      describe 'doing x' do
+        it "first" do
+        ^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 5, 8, 11.
+          expect(foo).to be(bar)
+        end
+        it "second" do
+        ^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2, 8, 11.
+          expect(foo).to be(bar)
+        end
+        it "third" do
+        ^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2, 5, 11.
+          expect(foo).to be(bar)
+        end
+        it "fourth" do
+        ^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2, 5, 8.
+          expect(foo).to be(bar)
+        end
+      end
+    RUBY
+  end
+
+  it 'correctly reports duplicates with string interpolation' do
+    expect_offense(<<~RUBY)
+      describe 'doing x' do
+        let(:date) { '2024-06-25' }
+
+        it { expect(subject).to be_urgent(order, now: T("\#{date}T12:00")) }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 5.
+        it { expect(subject).to be_urgent(order, now: T("\#{date}T12:00")) }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 4.
+      end
+    RUBY
+  end
+
+  it 'does not flag examples with different string interpolation values' do
+    expect_no_offenses(<<~RUBY)
+      describe 'doing x' do
+        let(:date) { '2024-06-25' }
+
+        it { expect(subject).to be_urgent(order, now: T("\#{date}T12:00")) }
+        it { expect(subject).to be_urgent(order, now: T("\#{date}T17:00")) }
+      end
+    RUBY
+  end
+
+  it 'handles one-liner examples with duplicates' do
+    expect_offense(<<~RUBY)
+      describe 'doing x' do
+        it { is_expected.to be_valid }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 3, 4.
+        it { is_expected.to be_valid }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2, 4.
+        it { is_expected.to be_valid }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2, 3.
+      end
+    RUBY
+  end
+
+  it 'shows line numbers for examples formatted differently but with ' \
+     'same AST' do
+    expect_offense(<<~RUBY)
+      describe 'doing x' do
+        it "does x" do
+        ^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 5.
+          expect(foo).to be(bar)
+        end
+        it "does y" do expect(foo).to be(bar); end
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2.
+      end
+    RUBY
+  end
+
+  it 'correctly identifies repeated examples across mixed formatting' do
+    expect_offense(<<~RUBY)
+      describe 'doing x' do
+        it "multiline" do
+        ^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 5.
+          expect(foo).to eq(bar)
+        end
+        it("single line") { expect(foo).to eq(bar) }
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2.
+      end
+    RUBY
+  end
+
+  it 'handles multiple examples on same line correctly' do
+    expect_offense(<<~RUBY)
+      describe 'doing x' do
+        it "first" do
+        ^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 5.
+          expect(foo).to eq(bar)
+        end
+        it("second") { expect(foo).to eq(bar) }; it("third") { expect(foo).to eq(bar) }
+                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2, 5.
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2, 5.
+      end
+    RUBY
+  end
+
+  it 'does not confuse examples in nested contexts with same implementation' do
+    expect_no_offenses(<<~RUBY)
+      describe 'doing x' do
+        context 'context A' do
+          it "does x" do
+            expect(foo).to be(bar)
+          end
+        end
+
+        context 'context B' do
+          it "does x" do
+            expect(foo).to be(bar)
+          end
+        end
+      end
+    RUBY
+  end
+
+  it 'flags duplicates only within the same example group' do
+    expect_offense(<<~RUBY)
+      describe 'doing x' do
+        it "first" do
+        ^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 5.
+          expect(foo).to be(bar)
+        end
+        it "second" do
+        ^^^^^^^^^^^^^^ Don't repeat examples within an example group. Repeated on line(s) 2.
+          expect(foo).to be(bar)
+        end
+
+        context 'different scope' do
+          it "third" do
+            expect(foo).to be(bar)
+          end
+        end
+      end
+    RUBY
+  end
 end