Rails 6.1 deprecates the use of exit statements in transaction

Rails 6.1 deprecates the use of return, break or throw to exit a transaction block.

return / break

1>> Post.transaction do
2>>   @post.update(post_params)
3>>
4>>   break # or return
5>> end
6
7# => TRANSACTION (0.1ms)  begin transaction
8# => DEPRECATION WARNING: Using `return`, `break` or `throw` to exit a transaction block is
9# => deprecated without replacement. If the `throw` came from
10# => `Timeout.timeout(duration)`, pass an exception class as a second
11# => argument so it doesn't use `throw` to abort its block. This results
12# => in the transaction being committed, but in the next release of Rails
13# => it will rollback.
14# => TRANSACTION (0.8ms)  commit transaction
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throw

1>> Timeout.timeout(1) do
2>>   Post.transaction do
3>>     @post.update(post_params)
4>>
5>>     sleep 3 # simulate slow request
6>>   end
7>> end
8
9# => TRANSACTION (0.1ms)  begin transaction
10# => DEPRECATION WARNING: Using `return`, `break` or `throw` to exit a transaction block is
11# => deprecated without replacement. If the `throw` came from
12# => `Timeout.timeout(duration)`, pass an exception class as a second
13# => argument so it doesn't use `throw` to abort its block. This results
14# => in the transaction being committed, but in the next release of Rails
15# => it will rollback.
16# => TRANSACTION (1.6ms)  commit transaction
17# => Completed 500 Internal Server Error in 1022ms (ActiveRecord: 3.2ms | Allocations: 9736)
18# => Timeout::Error (execution expired)
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Here, even when the error was thrown the transaction is committed. This is something which is going to change in the future versions.

This is done because currently, when a transaction block is wrapped in Timeout.timeout(duration) i.e. without second argument(an exception class) then it uses throw to exit the transaction.

Solution

1>> Timeout.timeout(1, Timeout::Error) do
2>>   Post.transaction do
3>>     @post.update(post_params)
4>>
5>>     sleep 3 # simulate slow request
6>>   end
7>> end
8
9# => TRANSACTION (0.1ms)  begin transaction
10# => TRANSACTION (0.7ms)  rollback transaction
11# => Timeout::Error (execution expired)
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Check out the pull request for more details on this.