*   Allow a job to retry indefinitely

    The `attempts` parameter of the `retry_on` method now accepts the
    symbol reference `:unlimited` in addition to a specific number of retry
    attempts to allow a developer to specify that a job should retry
    forever until it succeeds.

        class MyJob < ActiveJob::Base
          retry_on(AlwaysRetryException, attempts: :unlimited)

          # the actual job code
        end

    *Daniel Morton*

*   Added possibility to check on `:priority` in test helper methods
    `assert_enqueued_with` and `assert_performed_with`.

    *Wojciech Wnętrzak*

*   OpenSSL constants are now used for Digest computations.

    *Dirkjan Bussink*

*   Add a Serializer for the Range class.

    This should allow things like `MyJob.perform_later(range: 1..100)`.

*   Communicate enqueue failures to callers of `perform_later`.

    `perform_later` can now optionally take a block which will execute after
    the adapter attempts to enqueue the job. The block will receive the job
    instance as an argument even if the enqueue was not successful.
    Additionally, `ActiveJob` adapters now have the ability to raise an
    `ActiveJob::EnqueueError` which will be caught and stored in the job
    instance so code attempting to enqueue jobs can inspect any raised
    `EnqueueError` using the block.

        MyJob.perform_later do |job|
          unless job.successfully_enqueued?
            if job.enqueue_error&.message == "Redis was unavailable"
              # invoke some code that will retry the job after a delay
            end
          end
        end

    *Daniel Morton*

*   Don't log rescuable exceptions defined with `rescue_from`.

    *Hu Hailin*

*   Allow `rescue_from` to rescue all exceptions.

    *Adrianna Chang*, *Étienne Barrié*


Please check [6-1-stable](https://github.com/rails/rails/blob/6-1-stable/activejob/CHANGELOG.md) for previous changes.