[Fix rubocop#1427] Fix wrong autocorrect for Rails/UniqBeforePluck …

…with multi-line expression

This introduces a bit of whitespace when the expression spans multiple lines, but that seesm fine

changelog/fix_wrong_autocorrect_rails_pluck_uniq.md

@@ -0,0 +1 @@
+* [#1427](https://github.com/rubocop/rubocop-rails/issues/1427): Fix an error for `Rails/UniqBeforePluck` when `pluck` and `unique` are on different lines. ([@earlopain][])

lib/rubocop/cop/rails/uniq_before_pluck.rb

@@ -51,51 +51,29 @@ class UniqBeforePluck < Base
 
         MSG = 'Use `distinct` before `pluck`.'
         RESTRICT_ON_SEND = %i[uniq].freeze
-        NEWLINE = "\n"
-        PATTERN = '[!^block (send (send %<type>s :pluck ...) :uniq ...)]'
 
-        def_node_matcher :conservative_node_match, format(PATTERN, type: 'const')
-
-        def_node_matcher :aggressive_node_match, format(PATTERN, type: '_')
+        def_node_matcher :uniq_before_pluck, '[!^block $(send $(send _ :pluck ...) :uniq ...)]'
 
         def on_send(node)
-          uniq = if style == :conservative
-                   conservative_node_match(node)
-                 else
-                   aggressive_node_match(node)
-                 end
-
-          return unless uniq
+          uniq_before_pluck(node) do |uniq_node, pluck_node|
+            next if style == :conservative && !pluck_node.receiver&.const_type?
 
-          add_offense(node.loc.selector) do |corrector|
-            autocorrect(corrector, node)
+            add_offense(uniq_node.loc.selector) do |corrector|
+              autocorrect(corrector, uniq_node, pluck_node)
+            end
           end
         end
 
         private
 
-        def autocorrect(corrector, node)
-          method = node.method_name
+        def autocorrect(corrector, uniq_node, pluck_node)
+          corrector.remove(range_with_surrounding_space(uniq_node.loc.selector, newlines: false))
+          corrector.remove(uniq_node.loc.dot) if uniq_node.loc.dot
 
-          corrector.remove(dot_method_with_whitespace(method, node))
-          if (dot = node.receiver.loc.dot)
+          if (dot = pluck_node.loc.dot)
             corrector.insert_before(dot.begin, '.distinct')
           else
-            corrector.insert_before(node.receiver, 'distinct.')
-          end
-        end
-
-        def dot_method_with_whitespace(method, node)
-          range_between(dot_method_begin_pos(method, node), node.loc.selector.end_pos)
-        end
-
-        def dot_method_begin_pos(method, node)
-          lines = node.source.split(NEWLINE)
-
-          if lines.last.strip == ".#{method}"
-            node.source.rindex(NEWLINE)
-          else
-            node.loc.dot.begin_pos
+            corrector.insert_before(pluck_node, 'distinct.')
           end
         end
       end

spec/rubocop/cop/rails/uniq_before_pluck_spec.rb

@@ -22,6 +22,7 @@
 
       expect_correction(<<~RUBY)
         Model.distinct.pluck(:name)
+          
       RUBY
     end
 
@@ -34,6 +35,22 @@
 
       expect_correction(<<~RUBY)
         Model.distinct.pluck(:name)
+
+      RUBY
+    end
+
+    it 'corrects when uniq and pluck are on different lines' do
+      expect_offense(<<~RUBY)
+        Model
+          .pluck(:name)
+          .uniq
+           ^^^^ Use `distinct` before `pluck`.
+      RUBY
+
+      expect_correction(<<~RUBY)
+        Model
+          .distinct.pluck(:name)
+          
       RUBY
     end
 
@@ -85,6 +102,12 @@
         instance.assoc.pluck(:name).uniq
       RUBY
     end
+
+    it 'ignores uniq without an receiver' do
+      expect_no_offenses(<<~RUBY)
+        pluck(:name).uniq
+      RUBY
+    end
   end
 
   context 'when the enforced mode is aggressive' do