diff options
Diffstat (limited to 'activerecord')
8 files changed, 80 insertions, 36 deletions
diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md index 50a0b291b3..faab0f9554 100644 --- a/activerecord/CHANGELOG.md +++ b/activerecord/CHANGELOG.md @@ -1,3 +1,23 @@ +* Rework `ActiveRecord::Relation#last` + + 1. Always find last with ruby if relation is loaded + 2. Always use SQL instead if relation is not loaded. + 3. Deprecated relation loading when SQL order can not be automatically reversed + + Topic.order("title").load.last(3) + # before: SELECT ... + # after: No SQL + + Topic.order("title").last + # before: SELECT * FROM `topics` + # after: SELECT * FROM `topics` ORDER BY `topics`.`title` DESC LIMIT 1 + + Topic.order("coalesce(author, title)").last + # before: SELECT * FROM `topics` + # after: Deprecation Warning for irreversible order + + *Bogdan Gusiev* + * `ActiveRecord::Relation#reverse_order` throws `ActiveRecord::IrreversibleOrderError` when the order can not be reversed using current trivial algorithm. Also raises the same error when `#reverse_order` is called on diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb index 4a31a1aa84..fdffc3e6b9 100644 --- a/activerecord/lib/active_record/base.rb +++ b/activerecord/lib/active_record/base.rb @@ -132,9 +132,6 @@ module ActiveRecord #:nodoc: # end # end # - # You can alternatively use <tt>self[:attribute]=(value)</tt> and <tt>self[:attribute]</tt> - # or <tt>write_attribute(:attribute, value)</tt> and <tt>read_attribute(:attribute)</tt>. - # # == Attribute query methods # # In addition to the basic accessors, query methods are also automatically available on the Active Record object. diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb index 7a2a1a0e33..7e0c9f7837 100644 --- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb +++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb @@ -69,7 +69,11 @@ module ActiveRecord end undef_method :select_rows - # Executes the SQL statement in the context of this connection. + # Executes the SQL statement in the context of this connection and returns + # the raw result from the connection adapter. + # Note: depending on your database connector, the result returned by this + # method may be manually memory managed. Consider using the exec_query + # wrapper instead. def execute(sql, name = nil) end undef_method :execute diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb index 3e84786be0..5a9020ead5 100644 --- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb @@ -980,7 +980,6 @@ module ActiveRecord when 3; 'mediumint' when nil, 4; 'int' when 5..8; 'bigint' - when 11; 'int(11)' # backward compatibility with Rails 2.0 else raise(ActiveRecordError, "No integer type has byte size #{limit}") end end diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb index 6c15facf3b..8c7cfae7c1 100644 --- a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb +++ b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb @@ -128,6 +128,8 @@ module ActiveRecord # Executes an SQL statement, returning a PGresult object on success # or raising a PGError exception otherwise. + # Note: the PGresult object is manually memory managed; if you don't + # need it specifically, you many want consider the exec_query wrapper. def execute(sql, name = nil) log(sql, name) do @connection.async_exec(sql) diff --git a/activerecord/lib/active_record/migration/compatibility.rb b/activerecord/lib/active_record/migration/compatibility.rb index 5d742b523b..45e35a4f71 100644 --- a/activerecord/lib/active_record/migration/compatibility.rb +++ b/activerecord/lib/active_record/migration/compatibility.rb @@ -30,6 +30,19 @@ module ActiveRecord end end + def change_table(table_name, options = {}) + if block_given? + super(table_name, options) do |t| + class << t + prepend TableDefinition + end + yield t + end + else + super + end + end + def add_reference(*, **options) options[:index] ||= false super diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb index 3f5d6de78a..5d4a045097 100644 --- a/activerecord/lib/active_record/relation/finder_methods.rb +++ b/activerecord/lib/active_record/relation/finder_methods.rb @@ -145,15 +145,23 @@ module ActiveRecord # # [#<Person id:4>, #<Person id:3>, #<Person id:2>] def last(limit = nil) - if limit - if order_values.empty? && primary_key - order(arel_table[primary_key].desc).limit(limit).reverse - else - to_a.last(limit) - end - else - find_last - end + return find_last(limit) if loaded? + + result = order_values.empty? && primary_key ? order(arel_table[primary_key].desc) : reverse_order + result = result.limit!(limit || 1) + limit ? result.reverse : result.first + rescue ActiveRecord::IrreversibleOrderError + ActiveSupport::Deprecation.warn(<<-WARNING.squish) + Finding a last element by loading the relation when SQL ORDER + can not be reversed is deprecated. + Rails 5.1 will raise ActiveRecord::IrreversibleOrderError in this case. + Please call `to_a.last` if you still want to load the relation. + WARNING + find_last(limit) + end + + def find_last(limit) + limit ? to_a.last(limit) : to_a.last end # Same as #last but raises ActiveRecord::RecordNotFound if no record @@ -523,19 +531,6 @@ module ActiveRecord relation.limit(limit).to_a end - def find_last - if loaded? - @records.last - else - @last ||= - if limit_value - to_a.last - else - reverse_order.limit(1).to_a.first - end - end - end - private def find_nth_with_limit_and_offset(index, limit, offset:) # :nodoc: diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb index 75a74c052d..cbeb37dd22 100644 --- a/activerecord/test/cases/finder_test.rb +++ b/activerecord/test/cases/finder_test.rb @@ -506,7 +506,7 @@ class FinderTest < ActiveRecord::TestCase end end - def test_take_and_first_and_last_with_integer_should_use_sql_limit + def test_take_and_first_and_last_with_integer_should_use_sql assert_sql(/LIMIT|ROWNUM <=/) { Topic.take(3).entries } assert_sql(/LIMIT|ROWNUM <=/) { Topic.first(2).entries } assert_sql(/LIMIT|ROWNUM <=/) { Topic.last(5).entries } @@ -516,16 +516,30 @@ class FinderTest < ActiveRecord::TestCase assert_equal Topic.order("title").to_a.last(2), Topic.order("title").last(2) end - def test_last_with_integer_and_order_should_not_use_sql_limit - query = assert_sql { Topic.order("title").last(5).entries } - assert_equal 1, query.length - assert_no_match(/LIMIT/, query.first) + def test_last_with_integer_and_order_should_use_sql + relation = Topic.order("title") + assert_queries(1) { relation.last(5) } + assert !relation.loaded? end - def test_last_with_integer_and_reorder_should_not_use_sql_limit - query = assert_sql { Topic.reorder("title").last(5).entries } - assert_equal 1, query.length - assert_no_match(/LIMIT/, query.first) + def test_last_with_integer_and_reorder_should_use_sql + relation = Topic.reorder("title") + assert_queries(1) { relation.last(5) } + assert !relation.loaded? + end + + def test_last_on_loaded_relation_should_not_use_sql + relation = Topic.limit(10).load + assert_no_queries do + relation.last + relation.last(2) + end + end + + def test_last_with_irreversible_order + assert_deprecated do + Topic.order("coalesce(author_name, title)").last + end end def test_take_and_first_and_last_with_integer_should_return_an_array |