ActiveSupport::TaggedLogging does not persist context in a Fiber

[rafadc]

Steps to reproduce

In a new Rails application in the console just type:

logger = ActiveSupport::TaggedLogging.new(Logger.new(STDOUT))
logger.tagged('TAG') { Fiber.new{logger.info 'Stuff'}.resume }

This is similar (but not equal) to: #28156 In that issue the conversation is around threads.

Expected behavior

That should output:

[TAG] Stuff

Actual behavior

The output is

Stuff

and the tags are lost

Comments

The behaviour for threads is tested in: https://github.com/rails/rails/blob/v6.0.0/activesupport/test/tagged_logging_test.rb#L75-L84

but there is no information for Fibers. The current implementation does not pass the tags for threads (and probably it is not easy to do) but making it work for Fibers probably should be just changing this method

rails/activesupport/lib/active_support/tagged_logging.rb

Lines 51 to 55 in 88fe8d9

	def current_tags
	# We use our object ID here to avoid conflicting with other instances
	thread_key = @thread_key ||= "activesupport_tagged_logging_tags:#{object_id}"
	Thread.current[thread_key] ||= []
	end

to use Thread.current.current_variable_set and Thread.current.current_variable_getinstead because:

Thread.current[:fiber_local_var] = 'Result'
Fiber.new do
  puts Thread.current[:fiber_local_var]
end.resume
# => <Empty output>

Thread.current.thread_variable_set(:thread_local_var, 'Result')
Fiber.new do
  puts Thread.current.thread_variable_get(:thread_local_var)
end.resume
# => "Result"

I can create the PR myself but I'd first love to know if what I am saying makes sense or you explicitly don't want this to work for Fibers. In such case I can PR a test that intentionally excludes Fibers so it is explicit.

System configuration

Rails version: 6.0.0

Ruby version: 2.6.2p47

Thanks a lot!

[rails-bot]

This issue has been automatically marked as stale because it has not been commented on for at least three months.
The resources of the Rails team are limited, and so we are asking for your help.
If you can still reproduce this error on the 6-0-stable branch or on master, please reply with all of the information you have about it in order to keep the issue open.
Thank you for all your contributions.

[rafadc]

The issue is still relevant in Rails 6.0.2.1

[rails-bot]

This issue has been automatically marked as stale because it has not been commented on for at least three months.
The resources of the Rails team are limited, and so we are asking for your help.
If you can still reproduce this error on the 6-0-stable branch or on master, please reply with all of the information you have about it in order to keep the issue open.
Thank you for all your contributions.

[leehambley]

The issue is still relevant in 6.0.2.2

[rails-bot]

This issue has been automatically marked as stale because it has not been commented on for at least three months.
The resources of the Rails team are limited, and so we are asking for your help.
If you can still reproduce this error on the 6-0-stable branch or on master, please reply with all of the information you have about it in order to keep the issue open.
Thank you for all your contributions.