Merge pull request #36740 from stanhu/sh-fix-index-exists-postgresql-partial-index

Fix index_exists? for PostgreSQL expression indexes

activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb

@@ -100,7 +100,7 @@ def indexes(table_name)
       def index_exists?(table_name, column_name, options = {})
         column_names = Array(column_name).map(&:to_s)
         checks = []
-        checks << lambda { |i| i.columns == column_names }
+        checks << lambda { |i| Array(i.columns) == column_names }
         checks << lambda { |i| i.unique } if options[:unique]
         checks << lambda { |i| i.name == options[:name].to_s } if options[:name]
 

activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb

@@ -240,9 +240,11 @@ def test_partial_index
 
       def test_expression_index
         with_example_table do
-          @connection.add_index "ex", "mod(id, 10), abs(number)", name: "expression"
+          expr = "mod(id, 10), abs(number)"
+          @connection.add_index "ex", expr, name: "expression"
           index = @connection.indexes("ex").find { |idx| idx.name == "expression" }
-          assert_equal "mod(id, 10), abs(number)", index.columns
+          assert_equal expr, index.columns
+          assert_equal true, @connection.index_exists?("ex", expr, name: "expression")
         end
       end