Checklist

• 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

• default_exchange config have no effect #3926

Possible Duplicates

• None

Environment & Settings

Celery version: 4.3.0

software -> celery:4.3.0 (rhubarb) kombu:4.6.4 py:3.6.0
            billiard:3.6.1.0 librabbitmq:2.0.0
platform -> system:Linux arch:64bit, ELF
            kernel version:4.19.71-1-lts imp:CPython
loader   -> celery.loaders.default.Loader
settings -> transport:librabbitmq results:disabled

Steps to Reproduce

Required Dependencies

• Minimal Python Version: 3.6.0
• Minimal Celery Version: 4.3.0
• Minimal Kombu Version: 4.6.4
• Minimal Broker Version: RabbitMQ 3.7.15
• Minimal Result Backend Version: N/A or Unknown
• Minimal OS and/or Kernel Version: Linux 4.19.71-1-lts
• Minimal Broker Client Version: N/A or Unknown
• Minimal Result Backend Client Version: N/A or Unknown

Python Packages

amqp==2.5.1
asn1crypto==0.24.0
atomicwrites==1.3.0
attrs==19.1.0
Automat==0.7.0
backcall==0.1.0
billiard==3.6.1.0
case==1.5.3
celery==4.3.0
cffi==1.12.3
constantly==15.1.0
cryptography==2.7
cssselect==1.1.0
decorator==4.4.0
hyperlink==19.0.0
idna==2.8
importlib-metadata==0.23
incremental==17.5.0
ipython==7.8.0
ipython-genutils==0.2.0
jedi==0.15.1
kombu==4.6.4
librabbitmq==2.0.0
linecache2==1.0.0
lxml==4.4.1
mock==3.0.5
more-itertools==7.2.0
mysqlclient==1.4.4
nose==1.3.7
packaging==19.2
parsel==1.5.2
parso==0.5.1
pexpect==4.7.0
pickleshare==0.7.5
pluggy==0.13.0
prompt-toolkit==2.0.9
ptyprocess==0.6.0
py==1.8.0
pyasn1==0.4.7
pyasn1-modules==0.2.6
pycparser==2.19
PyDispatcher==2.0.5
Pygments==2.4.2
PyHamcrest==1.9.0
pyOpenSSL==19.0.0
pyparsing==2.4.2
pytest==5.2.1
pytz==2019.2
queuelib==1.5.0
Scrapy==1.7.3
scrapy-selenium==0.0.7
selenium==3.141.0
service-identity==18.1.0
six==1.12.0
SQLAlchemy==1.3.8
traceback2==1.4.0
traitlets==4.3.2
Twisted==19.7.0
unittest2==1.1.0
urllib3==1.25.6
vine==1.3.0
w3lib==1.21.0
wcwidth==0.1.7
zipp==0.6.0
zope.interface==4.6.0

Other Dependencies

Minimally Reproducible Test Case

broker_url = 'amqp://guest:guest@localhost:5672//'

task_default_queue = 'default'
task_default_exchange = 'tasks'
task_default_exchange_type = 'topic'
task_default_routing_key = 'tasks.default'
task_queues = (
    Queue('default',   routing_key='tasks.#'),
    Queue('test', routing_key='test.#'),
)

app = Celery('scan_worker')
app.conf.task_default_exchange = 'tasks'
app.conf.task_default_exchange_type = 'topic'
app.config_from_object('test_celery.celeryconfig', force=True)

Expected Behavior

According to the document:

If you don't set the exchange or exchange type values for a key, these will be taken from the task_default_exchange and task_default_exchange_type settings

The worker should automatically create queues that binding to the exchange with task_default_exchange and task_default_exchange_type

Actual Behavior

The output of the command celery worker -A test_celery -l info:

 -------------- celery@arch v4.3.0 (rhubarb)
---- **** ----- 
--- * ***  * -- Linux-4.19.71-1-lts-x86_64-with-arch 2019-10-10 20:13:55
-- * - **** --- 
- ** ---------- [config]
- ** ---------- .> app:         scan_worker:0x7efdc5430a58
- ** ---------- .> transport:   amqp://guest:**@localhost:5672//
- ** ---------- .> results:     disabled://
- *** --- * --- .> concurrency: 9 (prefork)
-- ******* ---- .> task events: OFF (enable -E to monitor tasks in this worker)
--- ***** ----- 
 -------------- [queues]
                .> default          exchange=(direct) key=tasks.#
                .> test             exchange=(direct) key=test.#

the queues are bound to the exchange that not match task_default_exchange and task_default_exchange_type