Consider options when removing UNIQUE KEYs

activerecord/lib/active_record/connection_adapters/postgresql/schema_creation.rb

@@ -50,7 +50,7 @@ def visit_ExclusionConstraintDefinition(o)
           end
 
           def visit_UniqueKeyDefinition(o)
-            column_name = Array(o.columns).map { |column| quote_column_name(column) }.join(", ")
+            column_name = Array(o.column).map { |column| quote_column_name(column) }.join(", ")
 
             sql = ["CONSTRAINT"]
             sql << quote_column_name(o.name)

activerecord/lib/active_record/connection_adapters/postgresql/schema_definitions.rb

@@ -211,7 +211,7 @@ def export_name_on_schema_dump?
         end
       end
 
-      UniqueKeyDefinition = Struct.new(:table_name, :columns, :options) do
+      UniqueKeyDefinition = Struct.new(:table_name, :column, :options) do
         def name
           options[:name]
         end
@@ -227,6 +227,12 @@ def using_index
         def export_name_on_schema_dump?
           !ActiveRecord::SchemaDumper.unique_ignore_pattern.match?(name) if name
         end
+
+        def defined_for?(name: nil, column: nil, **options)
+          (name.nil? || self.name == name.to_s) &&
+            (column.nil? || Array(self.column) == Array(column).map(&:to_s)) &&
+            options.all? { |k, v| self.options[k].to_s == v.to_s }
+        end
       end
 
       # = Active Record PostgreSQL Adapter \Table Definition

activerecord/lib/active_record/connection_adapters/postgresql/schema_dumper.rb

@@ -54,7 +54,7 @@ def unique_keys_in_create(table, stream)
             if (unique_keys = @connection.unique_keys(table)).any?
               add_unique_key_statements = unique_keys.map do |unique_key|
                 parts = [
-                  "t.unique_key #{unique_key.columns.inspect}"
+                  "t.unique_key #{unique_key.column.inspect}"
                 ]
 
                 parts << "deferrable: #{unique_key.deferrable.inspect}" if unique_key.deferrable

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

@@ -747,7 +747,7 @@ def unique_key_options(table_name, column_name, options) # :nodoc:
           end
 
           options = options.dup
-          options[:name] ||= unique_key_name(table_name, column_name: column_name, **options)
+          options[:name] ||= unique_key_name(table_name, column: column_name, **options)
           options
         end
 
@@ -759,7 +759,7 @@ def unique_key_options(table_name, column_name, options) # :nodoc:
         # to provide this in a migration's +change+ method so it can be reverted.
         # In that case, +column_name+ will be used by #add_unique_key.
         def remove_unique_key(table_name, column_name = nil, **options)
-          unique_name_to_delete = unique_key_for!(table_name, column_name: column_name, **options).name
+          unique_name_to_delete = unique_key_for!(table_name, column: column_name, **options).name
 
           at = create_alter_table(table_name)
           at.drop_unique_key(unique_name_to_delete)
@@ -1030,22 +1030,22 @@ def exclusion_constraint_for!(table_name, expression: nil, **options)
 
           def unique_key_name(table_name, **options)
             options.fetch(:name) do
-              column_name_or_index_name = options.fetch(:column_name) || options[:using_index]
-              identifier = "#{table_name}_#{column_name_or_index_name}_unique"
+              column_or_index = Array(options[:column] || options[:using_index]).map(&:to_s)
+              identifier = "#{table_name}_#{column_or_index * '_and_'}_unique"
               hashed_identifier = Digest::SHA256.hexdigest(identifier).first(10)
 
               "uniq_rails_#{hashed_identifier}"
             end
           end
 
           def unique_key_for(table_name, **options)
-            unique_key_name = unique_key_name(table_name, **options)
-            unique_keys(table_name).detect { |unique_key| unique_key.name == unique_key_name }
+            name = unique_key_name(table_name, **options) unless options.key?(:column)
+            unique_keys(table_name).detect { |unique_key| unique_key.defined_for?(name: name, **options) }
           end
 
-          def unique_key_for!(table_name, column_name: nil, **options)
-            unique_key_for(table_name, column_name: column_name, **options) ||
-              raise(ArgumentError, "Table '#{table_name}' has no unique constraint for #{column_name || options}")
+          def unique_key_for!(table_name, column: nil, **options)
+            unique_key_for(table_name, column: column, **options) ||
+              raise(ArgumentError, "Table '#{table_name}' has no unique constraint for #{column || options}")
           end
 
           def data_source_sql(name = nil, type: nil)

activerecord/test/cases/migration/unique_key_test.rb

@@ -30,15 +30,15 @@ def test_unique_keys
             {
               name: "test_unique_keys_position_deferrable_false",
               deferrable: false,
-              columns: ["position_1"]
+              column: ["position_1"]
             }, {
               name: "test_unique_keys_position_deferrable_immediate",
               deferrable: :immediate,
-              columns: ["position_2"]
+              column: ["position_2"]
             }, {
               name: "test_unique_keys_position_deferrable_deferred",
               deferrable: :deferred,
-              columns: ["position_3"]
+              column: ["position_3"]
             }
           ]
 
@@ -48,7 +48,7 @@ def test_unique_keys
             constraint = unique_keys.find { |constraint| constraint.name == expected_constraint[:name] }
             assert_equal "test_unique_keys", constraint.table_name
             assert_equal expected_constraint[:name], constraint.name
-            assert_equal expected_constraint[:columns], constraint.columns
+            assert_equal expected_constraint[:column], constraint.column
             assert_equal expected_constraint[:deferrable], constraint.deferrable
           end
         end
@@ -75,7 +75,7 @@ def test_add_unique_key_without_deferrable
 
           constraint = unique_keys.first
           assert_equal "sections", constraint.table_name
-          assert_equal "uniq_rails_3d89d7e853", constraint.name
+          assert_equal "uniq_rails_1e07660b77", constraint.name
           assert_equal false, constraint.deferrable
         end
 
@@ -87,7 +87,7 @@ def test_add_unique_key_with_deferrable_false
 
           constraint = unique_keys.first
           assert_equal "sections", constraint.table_name
-          assert_equal "uniq_rails_3d89d7e853", constraint.name
+          assert_equal "uniq_rails_1e07660b77", constraint.name
           assert_equal false, constraint.deferrable
         end
 
@@ -99,7 +99,7 @@ def test_add_unique_key_with_deferrable_immediate
 
           constraint = unique_keys.first
           assert_equal "sections", constraint.table_name
-          assert_equal "uniq_rails_3d89d7e853", constraint.name
+          assert_equal "uniq_rails_1e07660b77", constraint.name
           assert_equal :immediate, constraint.deferrable
         end
 
@@ -111,7 +111,7 @@ def test_add_unique_key_with_deferrable_deferred
 
           constraint = unique_keys.first
           assert_equal "sections", constraint.table_name
-          assert_equal "uniq_rails_3d89d7e853", constraint.name
+          assert_equal "uniq_rails_1e07660b77", constraint.name
           assert_equal :deferred, constraint.deferrable
         end
 
@@ -157,7 +157,7 @@ def test_add_unique_key_with_name_and_using_index
           constraint = unique_keys.first
           assert_equal "sections", constraint.table_name
           assert_equal "unique_constraint", constraint.name
-          assert_equal ["position"], constraint.columns
+          assert_equal ["position"], constraint.column
           assert_equal :immediate, constraint.deferrable
         end
 
@@ -171,7 +171,7 @@ def test_add_unique_key_with_only_using_index
           constraint = unique_keys.first
           assert_equal "sections", constraint.table_name
           assert_equal "uniq_rails_79b901ffb4", constraint.name
-          assert_equal ["position"], constraint.columns
+          assert_equal ["position"], constraint.column
           assert_equal false, constraint.deferrable
         end
 
@@ -184,16 +184,21 @@ def test_add_unique_key_with_columns_and_using_index
         end
 
         def test_remove_unique_key
-          assert_equal 0, @connection.unique_keys("sections").size
+          @connection.add_unique_key :sections, [:position], name: :unique_section_position
+          assert_equal 1, @connection.unique_keys("sections").size
+          @connection.remove_unique_key :sections, name: :unique_section_position
+          assert_empty @connection.unique_keys("sections")
+        end
 
-          @connection.add_unique_key :sections, [:position], name: "unique_section_position"
+        def test_remove_unique_key_by_column
+          @connection.add_unique_key :sections, [:position]
           assert_equal 1, @connection.unique_keys("sections").size
-          @connection.remove_unique_key :sections, name: "unique_section_position"
-          assert_equal 0, @connection.unique_keys("sections").size
+          @connection.remove_unique_key :sections, [:position]
+          assert_empty @connection.unique_keys("sections")
         end
 
         def test_remove_non_existing_unique_key
-          assert_raises(ArgumentError) do
+          assert_raises(ArgumentError, match: /Table 'sections' has no unique constraint/) do
             @connection.remove_unique_key :sections, name: "nonexistent"
           end
         end