Merge pull request #2156 from rubocop/preserve-the-order-or-lets

Preserve the order of declarations when auto-correcting

Author: r7kamura

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Master (Unreleased)
 
+- `RSpec/ScatteredLet` now preserves the order of `let`s during auto-correction. ([@Darhazer])
 - Fix a false negative for `RSpec/EmptyLineAfterFinalLet` inside `shared_examples` / `include_examples` / `it_behaves_like` blocks. ([@Darhazer])
 
 ## 3.9.0 (2026-01-07)

lib/rubocop/cop/rspec/scattered_let.rb

@@ -41,15 +41,21 @@ def on_block(node) # rubocop:disable InternalAffairs/NumblockHandler
 
         def check_let_declarations(body)
           lets = body.each_child_node.select { |node| let?(node) }
+          return if lets.empty?
 
           first_let = lets.first
+          reference_let = first_let
+
           lets.each_with_index do |node, idx|
-            next if node.sibling_index == first_let.sibling_index + idx
+            if node.sibling_index == first_let.sibling_index + idx
+              reference_let = node
+              next
+            end
 
             add_offense(node) do |corrector|
               RuboCop::RSpec::Corrector::MoveNode.new(
                 node, corrector, processed_source
-              ).move_after(first_let)
+              ).move_after(reference_let)
             end
           end
         end

spec/rubocop/cop/rspec/scattered_let_spec.rb

@@ -158,4 +158,33 @@
       end
     RUBY
   end
+
+  it 'preserves the order of `let`s' do
+    expect_offense(<<~RUBY)
+      describe User do
+        let(:a) { a }
+        let(:b) { b }
+        it { expect(subject.foo).to eq(a) }
+        let(:c) { c }
+        ^^^^^^^^^^^^^ Group all let/let! blocks in the example group together.
+        let(:d) { d }
+        ^^^^^^^^^^^^^ Group all let/let! blocks in the example group together.
+        it { expect(subject.bar).to eq(d) }
+        let(:e) { e }
+        ^^^^^^^^^^^^^ Group all let/let! blocks in the example group together.
+      end
+    RUBY
+
+    expect_correction(<<~RUBY)
+      describe User do
+        let(:a) { a }
+        let(:b) { b }
+        let(:c) { c }
+        let(:d) { d }
+        let(:e) { e }
+        it { expect(subject.foo).to eq(a) }
+        it { expect(subject.bar).to eq(d) }
+      end
+    RUBY
+  end
 end