Improve deprecation message for enqueue returning false

And make sure new applications in Rails 6.0 has this config enabled.

Also, improve test coverage and add a CHANGELOG entry.

2 files changed, 16 insertions, 1 deletions

diff --git a/activejob/CHANGELOG.md b/activejob/CHANGELOG.md
index 8e18faeb02..4acbe9a4e9 100644
--- a/activejob/CHANGELOG.md
+++ b/activejob/CHANGELOG.md
@@ -1,3 +1,10 @@
+*   Return false instead of the job instance when `enqueue` is aborted.
+
+    This will be the behavior in Rails 6.1 but it can be controlled now with
+    `config.active_job.return_false_on_aborted_enqueue`.
+
+    *Kir Shatrov*
+
 *   Keep executions for each specific declaration
 
     Each `retry_on` declaration has now its own specific executions counter. Before it was
diff --git a/activejob/lib/active_job/enqueuing.rb b/activejob/lib/active_job/enqueuing.rb
index 58e6d3348d..ce118c1e8a 100644
--- a/activejob/lib/active_job/enqueuing.rb
+++ b/activejob/lib/active_job/enqueuing.rb
@@ -49,21 +49,29 @@ module ActiveJob
       self.queue_name   = self.class.queue_name_from_part(options[:queue]) if options[:queue]
       self.priority     = options[:priority].to_i if options[:priority]
       successfully_enqueued = false
+
       run_callbacks :enqueue do
         if scheduled_at
           self.class.queue_adapter.enqueue_at self, scheduled_at
         else
           self.class.queue_adapter.enqueue self
         end
+
         successfully_enqueued = true
       end
+
       if successfully_enqueued
         self
       else
         if self.class.return_false_on_aborted_enqueue
           false
         else
-          ActiveSupport::Deprecation.warn "this will return false, set config.active_job.return_false_on_aborted_enqueue = true to remove deprecation."
+          ActiveSupport::Deprecation.warn(
+            "Rails 6.0 will return false when the enqueing is aborted. Make sure your code doesn't depend on it" \
+            " returning the instance of the job and set `config.active_job.return_false_on_aborted_enqueue = true`" \
+            " to remove the deprecations."
+          )
+
           self
         end
       end