Issue 1:
Checklist

I have verified that the issue exists against the master branch of Celery.

This has already been asked to the discussion group first.

I have read the relevant section in the

contribution guide

on reporting bugs.

I have checked the issues list

for similar or identical bug reports.

I have checked the pull requests list

for existing proposed fixes.

I have checked the commit log

to find out if the bug was already fixed in the master branch.

I have included all related issues and possible duplicate issues

in this issue (If there are none, check this box anyway).

Mandatory Debugging Information

I have included the output of celery -A proj report in the issue.

(if you are not able to do this, then at least specify the Celery

version affected).

I have verified that the issue exists against the master branch of Celery.

I have included the contents of pip freeze in the issue.

I have included all the versions of all the external dependencies required

to reproduce this bug.

Optional Debugging Information

I have tried reproducing the issue on more than one Python version

and/or implementation.

I have tried reproducing the issue on more than one message broker and/or

result backend.

I have tried reproducing the issue on more than one version of the message

broker and/or result backend.

I have tried reproducing the issue on more than one operating system.

I have tried reproducing the issue on more than one workers pool.

I have tried reproducing the issue with autoscaling, retries,

ETA/Countdown & rate limits disabled.

I have tried reproducing the issue after downgrading

and/or upgrading Celery and its dependencies.

Related Issues and Possible Duplicates

Related Issues

None

Possible Duplicates

None

Environment & Settings

Celery version: 4.4.4 (celery v4.4.3 and below work fine)

celery report Output:

Steps to Reproduce

Required Dependencies

Minimal Python Version: 3.7

Minimal Celery Version: 4.4.4

Minimal Kombu Version: N/A or Unknown

Minimal Broker Version: N/A or Unknown

Minimal Result Backend Version: N/A or Unknown

Minimal OS and/or Kernel Version: N/A or Unknown

Minimal Broker Client Version: N/A or Unknown

Minimal Result Backend Client Version: N/A or Unknown

Python Packages

pip freeze Output:

Other Dependencies

N/A

Minimally Reproducible Test Case

celery_app = Celery("worker", broker="amqp://guest@queue//")

celery_app.conf.task_routes = {"app.worker.test_celery": "main-queue"}

@celery_app.task(acks_late=True)
def test_celery(word: str):
return f"test task return {word}"

celery_app.send_task("app.worker.test_celery", args=["msg"])

Expected Behavior

The function should return successfully.

Actual Behavior

An error is thrown : No module named future in the celery package (in celery code, the error is at celery/backends/base.py: from future.utils import raise_with_traceback

Issue 2:
This one is simple to reproduce, I just upgraded to celery==4.4.4 and now my builds are broken.

[2020-06-03 09:48:39,517: DEBUG/MainProcess] | Worker: Preparing bootsteps.
[2020-06-03 09:48:39,518: DEBUG/MainProcess] | Worker: Building graph...
[2020-06-03 09:48:39,518: DEBUG/MainProcess] | Worker: New boot order: {StateDB, Beat, Timer, Hub, Pool, Autoscaler, Consumer}
[2020-06-03 09:48:39,522: DEBUG/MainProcess] | Consumer: Preparing bootsteps.
[2020-06-03 09:48:39,522: DEBUG/MainProcess] | Consumer: Building graph...
[2020-06-03 09:48:39,538: DEBUG/MainProcess] | Consumer: New boot order: {Connection, Events, Heart, Mingle, Gossip, Agent, Tasks, Control, event loop}
[2020-06-03 09:48:39,540: CRITICAL/MainProcess] Unrecoverable error: ModuleNotFoundError("No module named 'future'")
Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/kombu/utils/objects.py", line 42, in __get__
return obj.__dict__[self.__name__]
KeyError: 'backend'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/local/lib/python3.7/site-packages/celery/worker/worker.py", line 208, in start
self.blueprint.start(self)
File "/usr/local/lib/python3.7/site-packages/celery/bootsteps.py", line 115, in start
self.on_start()
File "/usr/local/lib/python3.7/site-packages/celery/apps/worker.py", line 139, in on_start
self.emit_banner()
File "/usr/local/lib/python3.7/site-packages/celery/apps/worker.py", line 154, in emit_banner
' \n', self.startup_info(artlines=not use_image))),
File "/usr/local/lib/python3.7/site-packages/celery/apps/worker.py", line 217, in startup_info
results=self.app.backend.as_uri(),
File "/usr/local/lib/python3.7/site-packages/kombu/utils/objects.py", line 44, in __get__
value = obj.__dict__[self.__name__] = self.__get(obj)
File "/usr/local/lib/python3.7/site-packages/celery/app/base.py", line 1232, in backend
return self._get_backend()
File "/usr/local/lib/python3.7/site-packages/celery/app/base.py", line 949, in _get_backend
self.loader)
File "/usr/local/lib/python3.7/site-packages/celery/app/backends.py", line 74, in by_url
return by_name(backend, loader), url
File "/usr/local/lib/python3.7/site-packages/celery/app/backends.py", line 54, in by_name
cls = symbol_by_name(backend, aliases)
File "/usr/local/lib/python3.7/site-packages/kombu/utils/imports.py", line 57, in symbol_by_name
module = imp(module_name, package=package, **kwargs)
File "/usr/local/lib/python3.7/importlib/__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
File "<frozen importlib._bootstrap>", line 983, in _find_and_load
File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 728, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "/usr/local/lib/python3.7/site-packages/celery/backends/base.py", line 10, in <module>
from future.utils import raise_with_traceback
ModuleNotFoundError: No module named 'future'

Running in a docker container using python:3.7-alpine as base image.