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Accept optional transaction args to #with_lock

Make #with_lock as expressive as calling #transaction and #lock!
individually to enable behavior like so:

    person.with_lock("FOR UPDATE NOWAIT", requires_new: true) do
      ...
    end

Helps teams who prefer #with_lock over #lock! to ensure the lock is
taken out within a transaction, even when advanced transaction control
is required without requiring redundant transaction blocks.
This commit is contained in:
John Mileham 2021-09-15 15:08:51 -04:00
parent 6d42731ded
commit b5e670a9dd
3 changed files with 43 additions and 3 deletions

View file

@ -1,3 +1,8 @@
* Accept optional transaction args to `ActiveRecord::Locking::Pessimistic#with_lock`
`#with_lock` now accepts transaction options like `requires_new:`,
`isolation:`, and `joinable:`
* Adds support for deferrable foreign key constraints in PostgreSQL.
By default, foreign key constraints in PostgreSQL are checked after each statement. This works for most use cases,

View file

@ -81,9 +81,15 @@ module ActiveRecord
# Wraps the passed block in a transaction, locking the object
# before yielding. You can pass the SQL locking clause
# as argument (see <tt>lock!</tt>).
def with_lock(lock = true)
transaction do
# as an optional argument (see <tt>#lock!</tt>).
#
# You can also pass options like <tt>requires_new:</tt>, <tt>isolation:</tt>,
# and <tt>joinable:</tt> to the wrapping transaction (see
# <tt>ActiveRecord::ConnectionAdapters::DatabaseStatements#transaction</tt>).
def with_lock(*args)
transaction_opts = args.extract_options!
lock = args.present? ? args.first : true
transaction(**transaction_opts) do
lock!(lock)
yield
end

View file

@ -738,6 +738,19 @@ unless in_memory_db?
assert_equal old, person.reload.first_name
end
def test_with_lock_configures_transaction
person = Person.find 1
Person.transaction do
outer_transaction = Person.connection.transaction_manager.current_transaction
assert_equal true, outer_transaction.joinable?
person.with_lock(requires_new: true, joinable: false) do
current_transaction = Person.connection.transaction_manager.current_transaction
assert_not_equal outer_transaction, current_transaction
assert_equal false, current_transaction.joinable?
end
end
end
if current_adapter?(:PostgreSQLAdapter)
def test_lock_sending_custom_lock_statement
Person.transaction do
@ -747,6 +760,22 @@ unless in_memory_db?
end
end
end
def test_with_lock_sets_isolation
person = Person.find 1
person.with_lock(isolation: :read_uncommitted) do
current_transaction = Person.connection.transaction_manager.current_transaction
assert_equal :read_uncommitted, current_transaction.isolation_level
end
end
def test_with_lock_locks_with_no_args
person = Person.find 1
assert_sql(/LIMIT \$?\d FOR UPDATE/i) do
person.with_lock do
end
end
end
end
def test_no_locks_no_wait