<h1 dir="auto">Checklist</h1>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have checked the <a href="https://github.com/celery/celery/issues?utf8=%E2%9C%93&amp;q=is%3Aissue+label%3A%22Category%3A+Documentation%22+">issues list</a><br>
for similar or identical bug reports.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have checked the <a href="https://github.com/celery/celery/pulls?q=is%3Apr+label%3A%22Category%3A+Documentation%22">pull requests list</a><br>
for existing proposed fixes.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have checked the <a href="https://github.com/celery/celery/commits/master">commit log</a><br>
to find out if the bug was already fixed in the master branch.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have included all related issues and possible duplicate issues in this issue<br>
(If there are none, check this box anyway).</li>
</ul>
<h2 dir="auto">Related Issues and Possible Duplicates</h2>
<h4 dir="auto">Related Issues</h4>
<ul dir="auto">
<li>Potentially related to <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="75915160" data-permission-text="Title is private" data-url="https://github.com/celery/celery/issues/2616" data-hovercard-type="issue" data-hovercard-url="/celery/celery/issues/2616/hovercard" href="https://github.com/celery/celery/issues/2616">#2616</a> although quite dated</li>
</ul>
<h4 dir="auto">Possible Duplicates</h4>
<ul dir="auto">
<li>None</li>
</ul>
<h1 dir="auto">Description</h1>
<p dir="auto">The documentation is unclear on the following points:</p>
<ol dir="auto">
<li>What happens when the number of pool connections goes above the limit specified by <a href="http://docs.celeryproject.org/en/latest/userguide/configuration.html#std:setting-broker_pool_limit" rel="nofollow">broker_pool_limit</a> and <a href="http://docs.celeryproject.org/en/latest/userguide/configuration.html#redis-max-connections" rel="nofollow">redis_max_connections</a></li>
<li>Which setting prevails?</li>
<li>Is there a way to choose the type of Redis pool?</li>
</ol>
<h1 dir="auto">Suggestions</h1>
<ol dir="auto">
<li>
<p dir="auto">By default Redis creates a <a href="https://redis-py.readthedocs.io/en/latest/#redis.ConnectionPool" rel="nofollow"><code class="notranslate">redis.connection.ConnectionPool</code></a> which raises a <code class="notranslate">redis.exceptions.ConnectionError</code> when celery attempts to execute a new task and all of the connections in the pool are exhausted.<br>
In contrast, the <a href="https://redis-py.readthedocs.io/en/latest/#redis.BlockingConnectionPool" rel="nofollow"><code class="notranslate">redis.connection.BlockingConnectionPool</code></a> does not raise an error and waits until a connection becomes available in the pool.<br>
The docs should warn that <code class="notranslate">redis_max_connections</code> will raise a redis exception in case the connections exceed the maximum.</p>
</li>
<li>
<p dir="auto">Unsure and untested, so not clear what to suggest here.</p>
</li>
<li>
<p dir="auto">The docs should probably mentions under <code class="notranslate">redis_max_connections</code> that choosing the type of redis pool is unsupported.</p>
</li>
</ol>
<h1 dir="auto">Checklist</h1>

<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have read the relevant section in the<br>
<a href="http://docs.celeryproject.org/en/latest/contributing.html#other-bugs" rel="nofollow">contribution guide</a><br>
on reporting bugs.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have checked the <a href="https://github.com/celery/celery/issues?q=is%3Aissue+label%3A%22Issue+Type%3A+Bug+Report%22+-label%3A%22Category%3A+Documentation%22">issues list</a><br>
for similar or identical bug reports.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have checked the <a href="https://github.com/celery/celery/pulls?q=is%3Apr+label%3A%22PR+Type%3A+Bugfix%22+-label%3A%22Category%3A+Documentation%22">pull requests list</a><br>
for existing proposed fixes.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have checked the <a href="https://github.com/celery/celery/commits/master">commit log</a><br>
txo find out if the bug was already fixed in the master branch.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have included all related issues and possible duplicate issues<br>
in this issue (If there are none, check this box anyway).</li>
</ul>
<h2 dir="auto">Mandatory Debugging Information</h2>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have included the output of <code class="notranslate">celery -A proj report</code> in the issue.<br>
(if you are not able to do this, then at least specify the Celery<br>
version affected).</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have verified that the issue exists against the <code class="notranslate">master</code> branch of Celery.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have included the contents of <code class="notranslate">pip freeze</code> in the issue.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have included all the versions of all the external dependencies required<br>
to reproduce this bug.</li>
</ul>
<h2 dir="auto">Optional Debugging Information</h2>

<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have tried reproducing the issue on more than one Python version<br>
and/or implementation.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have tried reproducing the issue on more than one message broker and/or<br>
result backend.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have tried reproducing the issue on more than one version of the message<br>
broker and/or result backend.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have tried reproducing the issue on more than one operating system.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have tried reproducing the issue on more than one workers pool.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have tried reproducing the issue with autoscaling, retries,<br>
ETA/Countdown &amp; rate limits disabled.</li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> I have tried reproducing the issue after downgrading<br>
and/or upgrading Celery and its dependencies.</li>
</ul>
<h2 dir="auto">Related Issues and Possible Duplicates</h2>

<h4 dir="auto">Related Issues</h4>
<ul dir="auto">
<li>None</li>
</ul>
<h4 dir="auto">Possible Duplicates</h4>
<ul dir="auto">
<li>None</li>
</ul>
<h2 dir="auto">Environment &amp; Settings</h2>

<p dir="auto"><strong>Celery version</strong>: v3.1.26 &amp; v4.2.1</p>

<details>
<summary><b><code class="notranslate">celery report</code> Output:</b></summary>
<p dir="auto">
</p><div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content=""><pre class="notranslate"><code class="notranslate"></code></pre></div>
<p dir="auto"></p>
</details>
<h1 dir="auto">Steps to Reproduce</h1>
<ul dir="auto">
<li>Create 2 django project running celery v3.1.26 and v4.2.1 respectively. And both the project using the same result backend and same broker url.</li>
<li>Execute a task with <code class="notranslate">task_id</code> in project with celery v3.1.26 and try to fetch the result of it in project with celery v4.2.1, you will get the <strong>KeyError: 'task_id'</strong></li>
</ul>
<p dir="auto">project running celeryv3.1.26</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="In [24]: variable_time.apply_async((15,), task_id='-2')                                                                                                                              
Out[24]: &lt;AsyncResult: -2&gt;

# Celery info

[2019-09-01 08:50:08,353: INFO/MainProcess] Received task: testing.tasks.variable_time[-2]
[2019-09-01 08:50:23,397: INFO/MainProcess] Task testing.tasks.variable_time[-2] succeeded in 15.037280982825905s: {'celery': 15}

# Settings
CELERY_RESULT_BACKEND = 'redis://localhost/0'
CELERY_BROKER_URL = 'redis://localhost:6379//'
CELERY_IMPORTS = ('testing.tasks', )
CELERY_ACCEPT_CONTENT = ['pickle', 'application/json', 'application/x-python-serialize']
CELERY_RESULT_SERIALIZER = 'pickle'
CELERY_TASK_SERIALIZER = 'pickle'
"><pre class="notranslate"><code class="notranslate">In [24]: variable_time.apply_async((15,), task_id='-2')                                                                                                                              
Out[24]: &lt;AsyncResult: -2&gt;

# Celery info

[2019-09-01 08:50:08,353: INFO/MainProcess] Received task: testing.tasks.variable_time[-2]
[2019-09-01 08:50:23,397: INFO/MainProcess] Task testing.tasks.variable_time[-2] succeeded in 15.037280982825905s: {'celery': 15}

# Settings
CELERY_RESULT_BACKEND = 'redis://localhost/0'
CELERY_BROKER_URL = 'redis://localhost:6379//'
CELERY_IMPORTS = ('testing.tasks', )
CELERY_ACCEPT_CONTENT = ['pickle', 'application/json', 'application/x-python-serialize']
CELERY_RESULT_SERIALIZER = 'pickle'
CELERY_TASK_SERIALIZER = 'pickle'

</code></pre></div>
<p dir="auto">project running celeryv4.1.26</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="In [41]: x = AsyncResult('-2')                                                                                                                                                       

In [42]: x.get()                                                                                                                                                                     
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
&lt;ipython-input-42-0c447e18adc3&gt; in &lt;module&gt;
----&gt; 1 x.get()

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/result.py in get(self, timeout, propagate, interval, no_ack, follow_parents, callback, on_message, on_interval, disable_sync_subtasks, EXCEPTION_STATES, PROPAGATE_STATES)
    221             propagate=propagate,
    222             callback=callback,
--&gt; 223             on_message=on_message,
    224         )
    225     wait = get  # deprecated alias to :meth:`get`.

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/backends/async.py in wait_for_pending(self, result, callback, propagate, **kwargs)
    186                          callback=None, propagate=True, **kwargs):
    187         self._ensure_not_eager()
--&gt; 188         for _ in self._wait_for_pending(result, **kwargs):
    189             pass
    190         return result.maybe_throw(callback=callback, propagate=propagate)

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/backends/async.py in _wait_for_pending(self, result, timeout, on_interval, on_message, **kwargs)
    248                           timeout=None, on_interval=None, on_message=None,
    249                           **kwargs):
--&gt; 250         self.on_wait_for_pending(result, timeout=timeout, **kwargs)
    251         prev_on_m, self.on_message = self.on_message, on_message
    252         try:

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/backends/redis.py in on_wait_for_pending(self, result, **kwargs)
    110         for meta in result._iter_meta():
    111             if meta is not None:
--&gt; 112                 self.on_state_change(meta, None)
    113 
    114     def stop(self):

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/backends/redis.py in on_state_change(self, meta, message)
     98 
     99     def on_state_change(self, meta, message):
--&gt; 100         super(ResultConsumer, self).on_state_change(meta, message)
    101         self._maybe_cancel_ready_task(meta)
    102 

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/backends/async.py in on_state_change(self, meta, message)
    279             self.on_message(meta)
    280         if meta['status'] in states.READY_STATES:
--&gt; 281             task_id = meta['task_id']
    282             try:
    283                 result = self._get_pending_result(task_id)

KeyError: 'task_id'


# Settings

CELERY_RESULT_BACKEND = 'redis://localhost/0'
CELERY_BROKER_URL = 'redis://localhost:6379//'
CELERY_IMPORTS = ('testing.tasks', )
CELERY_ACCEPT_CONTENT = ['pickle', 'application/json', 'application/x-python-serialize']
CELERY_RESULT_SERIALIZER = 'pickle'
CELERY_TASK_SERIALIZER = 'pickle'
                                                                                                                                                                    "><pre class="notranslate"><code class="notranslate">In [41]: x = AsyncResult('-2')                                                                                                                                                       

In [42]: x.get()                                                                                                                                                                     
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
&lt;ipython-input-42-0c447e18adc3&gt; in &lt;module&gt;
----&gt; 1 x.get()

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/result.py in get(self, timeout, propagate, interval, no_ack, follow_parents, callback, on_message, on_interval, disable_sync_subtasks, EXCEPTION_STATES, PROPAGATE_STATES)
    221             propagate=propagate,
    222             callback=callback,
--&gt; 223             on_message=on_message,
    224         )
    225     wait = get  # deprecated alias to :meth:`get`.

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/backends/async.py in wait_for_pending(self, result, callback, propagate, **kwargs)
    186                          callback=None, propagate=True, **kwargs):
    187         self._ensure_not_eager()
--&gt; 188         for _ in self._wait_for_pending(result, **kwargs):
    189             pass
    190         return result.maybe_throw(callback=callback, propagate=propagate)

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/backends/async.py in _wait_for_pending(self, result, timeout, on_interval, on_message, **kwargs)
    248                           timeout=None, on_interval=None, on_message=None,
    249                           **kwargs):
--&gt; 250         self.on_wait_for_pending(result, timeout=timeout, **kwargs)
    251         prev_on_m, self.on_message = self.on_message, on_message
    252         try:

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/backends/redis.py in on_wait_for_pending(self, result, **kwargs)
    110         for meta in result._iter_meta():
    111             if meta is not None:
--&gt; 112                 self.on_state_change(meta, None)
    113 
    114     def stop(self):

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/backends/redis.py in on_state_change(self, meta, message)
     98 
     99     def on_state_change(self, meta, message):
--&gt; 100         super(ResultConsumer, self).on_state_change(meta, message)
    101         self._maybe_cancel_ready_task(meta)
    102 

~/.virtualenvs/celery4-env-py3/lib/python3.6/site-packages/celery/backends/async.py in on_state_change(self, meta, message)
    279             self.on_message(meta)
    280         if meta['status'] in states.READY_STATES:
--&gt; 281             task_id = meta['task_id']
    282             try:
    283                 result = self._get_pending_result(task_id)

KeyError: 'task_id'


# Settings

CELERY_RESULT_BACKEND = 'redis://localhost/0'
CELERY_BROKER_URL = 'redis://localhost:6379//'
CELERY_IMPORTS = ('testing.tasks', )
CELERY_ACCEPT_CONTENT = ['pickle', 'application/json', 'application/x-python-serialize']
CELERY_RESULT_SERIALIZER = 'pickle'
CELERY_TASK_SERIALIZER = 'pickle'
                                                                                                                                                                    
</code></pre></div>
<h2 dir="auto">Required Dependencies</h2>

<ul dir="auto">
<li><strong>Minimal Python Version</strong>: N/A or Unknown</li>
<li><strong>Minimal Celery Version</strong>: N/A or Unknown</li>
<li><strong>Minimal Kombu Version</strong>: N/A or Unknown</li>
<li><strong>Minimal Broker Version</strong>: N/A or Unknown</li>
<li><strong>Minimal Result Backend Version</strong>: N/A or Unknown</li>
<li><strong>Minimal OS and/or Kernel Version</strong>: N/A or Unknown</li>
<li><strong>Minimal Broker Client Version</strong>: N/A or Unknown</li>
<li><strong>Minimal Result Backend Client Version</strong>: N/A or Unknown</li>
</ul>
<h3 dir="auto">Python Packages</h3>

<details>
<summary><b><code class="notranslate">pip freeze</code> Output:</b></summary>
<p dir="auto">
</p><div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="# Celery3
amqp==1.4.9
anyjson==0.3.3
appnope==0.1.0
backcall==0.1.0
billiard==3.3.0.23
celery==3.1.25
decorator==4.4.0
Django==2.2
ipdb==0.12.2
ipython==7.8.0
ipython-genutils==0.2.0
jedi==0.15.1
kombu==3.0.37
parso==0.5.1
pexpect==4.7.0
pickleshare==0.7.5
prompt-toolkit==2.0.9
ptyprocess==0.6.0
Pygments==2.4.2
pytz==2019.2
redis==2.10.6
six==1.12.0
sqlparse==0.3.0
traitlets==4.3.2
wcwidth==0.1.7

# Celery4 
alabaster==0.7.10
amqp==2.5.1
anaconda-client==1.6.14
anaconda-navigator==1.8.7
anaconda-project==0.8.2
appnope==0.1.0
appscript==1.0.1
asn1crypto==0.24.0
astroid==1.6.3
astropy==3.0.2
attrs==18.1.0
Babel==2.5.3
backcall==0.1.0
backports.shutil-get-terminal-size==1.0.0
beautifulsoup4==4.6.0
billiard==3.6.1.0
bitarray==0.8.1
bkcharts==0.2
blaze==0.11.3
bleach==2.1.3
bokeh==0.12.16
boto==2.48.0
Bottleneck==1.2.1
celery==4.4.0rc3
certifi==2018.4.16
cffi==1.11.5
chardet==3.0.4
click==6.7
cloudpickle==0.5.3
clyent==1.2.2
colorama==0.3.9
conda==4.5.4
conda-build==3.10.5
conda-verify==2.0.0
contextlib2==0.5.5
cryptography==2.2.2
cycler==0.10.0
Cython==0.28.2
cytoolz==0.9.0.1
dask==0.17.5
datashape==0.5.4
decorator==4.3.0
distributed==1.21.8
Django==2.2
docutils==0.14
entrypoints==0.2.3
et-xmlfile==1.0.1
fastcache==1.0.2
filelock==3.0.4
Flask==1.0.2
Flask-Cors==3.0.4
gevent==1.3.0
glob2==0.6
gmpy2==2.0.8
greenlet==0.4.13
h5py==2.7.1
heapdict==1.0.0
html5lib==1.0.1
idna==2.6
imageio==2.3.0
imagesize==1.0.0
importlib-metadata==0.19
ipdb==0.12.2
ipykernel==4.8.2
ipython==6.4.0
ipython-genutils==0.2.0
ipywidgets==7.2.1
isort==4.3.4
itsdangerous==0.24
jdcal==1.4
jedi==0.12.0
Jinja2==2.10
jsonschema==2.6.0
jupyter==1.0.0
jupyter-client==5.2.3
jupyter-console==5.2.0
jupyter-core==4.4.0
jupyterlab==0.32.1
jupyterlab-launcher==0.10.5
kiwisolver==1.0.1
kombu==4.6.4
lazy-object-proxy==1.3.1
llvmlite==0.23.1
locket==0.2.0
lxml==4.2.1
MarkupSafe==1.0
matplotlib==2.2.2
mccabe==0.6.1
mistune==0.8.3
mkl-fft==1.0.0
mkl-random==1.0.1
more-itertools==4.1.0
mpmath==1.0.0
msgpack-python==0.5.6
multipledispatch==0.5.0
mypy==0.650
mypy-extensions==0.4.1
navigator-updater==0.2.1
nbconvert==5.3.1
nbformat==4.4.0
networkx==2.1
nltk==3.3
nose==1.3.7
notebook==5.5.0
numba==0.38.0
numexpr==2.6.5
numpy==1.14.3
numpydoc==0.8.0
odo==0.5.1
olefile==0.45.1
openpyxl==2.5.3
packaging==17.1
pandas==0.23.0
pandocfilters==1.4.2
parso==0.2.0
partd==0.3.8
path.py==11.0.1
pathlib2==2.3.2
patsy==0.5.0
pep8==1.7.1
pexpect==4.5.0
pickleshare==0.7.4
Pillow==5.1.0
pkginfo==1.4.2
pluggy==0.6.0
ply==3.11
prompt-toolkit==1.0.15
psutil==5.4.5
ptyprocess==0.5.2
py==1.5.3
pycodestyle==2.4.0
pycosat==0.6.3
pycparser==2.18
pycrypto==2.6.1
pycurl==7.43.0.1
pyflakes==1.6.0
Pygments==2.2.0
pylint==1.8.4
pyodbc==4.0.23
pyOpenSSL==18.0.0
pyparsing==2.2.0
PySocks==1.6.8
pytest==3.5.1
pytest-arraydiff==0.2
pytest-astropy==0.3.0
pytest-doctestplus==0.1.3
pytest-openfiles==0.3.0
pytest-remotedata==0.2.1
python-dateutil==2.7.3
pytz==2018.4
PyWavelets==0.5.2
PyYAML==3.12
pyzmq==17.0.0
QtAwesome==0.4.4
qtconsole==4.3.1
QtPy==1.4.1
redis==2.10.6
requests==2.18.4
rope==0.10.7
ruamel-yaml==0.15.35
scikit-image==0.13.1
scikit-learn==0.19.1
scipy==1.1.0
seaborn==0.8.1
Send2Trash==1.5.0
simplegeneric==0.8.1
singledispatch==3.4.0.3
six==1.11.0
snowballstemmer==1.2.1
sortedcollections==0.6.1
sortedcontainers==1.5.10
Sphinx==1.7.4
sphinxcontrib-websupport==1.0.1
spyder==3.2.8
SQLAlchemy==1.2.7
sqlparse==0.3.0
statsmodels==0.9.0
sympy==1.1.1
tables==3.4.3
tblib==1.3.2
terminado==0.8.1
testpath==0.3.1
toolz==0.9.0
tornado==5.0.2
traitlets==4.3.2
typed-ast==1.1.0
typing==3.6.4
unicodecsv==0.14.1
urllib3==1.22
vine==1.3.0
wcwidth==0.1.7
webencodings==0.5.1
Werkzeug==0.14.1
widgetsnbextension==3.2.1
wrapt==1.10.11
xlrd==1.1.0
XlsxWriter==1.0.4
xlwings==0.11.8
xlwt==1.2.0
zict==0.1.3
zipp==0.6.0"><pre class="notranslate"><code class="notranslate"># Celery3
amqp==1.4.9
anyjson==0.3.3
appnope==0.1.0
backcall==0.1.0
billiard==3.3.0.23
celery==3.1.25
decorator==4.4.0
Django==2.2
ipdb==0.12.2
ipython==7.8.0
ipython-genutils==0.2.0
jedi==0.15.1
kombu==3.0.37
parso==0.5.1
pexpect==4.7.0
pickleshare==0.7.5
prompt-toolkit==2.0.9
ptyprocess==0.6.0
Pygments==2.4.2
pytz==2019.2
redis==2.10.6
six==1.12.0
sqlparse==0.3.0
traitlets==4.3.2
wcwidth==0.1.7

# Celery4 
alabaster==0.7.10
amqp==2.5.1
anaconda-client==1.6.14
anaconda-navigator==1.8.7
anaconda-project==0.8.2
appnope==0.1.0
appscript==1.0.1
asn1crypto==0.24.0
astroid==1.6.3
astropy==3.0.2
attrs==18.1.0
Babel==2.5.3
backcall==0.1.0
backports.shutil-get-terminal-size==1.0.0
beautifulsoup4==4.6.0
billiard==3.6.1.0
bitarray==0.8.1
bkcharts==0.2
blaze==0.11.3
bleach==2.1.3
bokeh==0.12.16
boto==2.48.0
Bottleneck==1.2.1
celery==4.4.0rc3
certifi==2018.4.16
cffi==1.11.5
chardet==3.0.4
click==6.7
cloudpickle==0.5.3
clyent==1.2.2
colorama==0.3.9
conda==4.5.4
conda-build==3.10.5
conda-verify==2.0.0
contextlib2==0.5.5
cryptography==2.2.2
cycler==0.10.0
Cython==0.28.2
cytoolz==0.9.0.1
dask==0.17.5
datashape==0.5.4
decorator==4.3.0
distributed==1.21.8
Django==2.2
docutils==0.14
entrypoints==0.2.3
et-xmlfile==1.0.1
fastcache==1.0.2
filelock==3.0.4
Flask==1.0.2
Flask-Cors==3.0.4
gevent==1.3.0
glob2==0.6
gmpy2==2.0.8
greenlet==0.4.13
h5py==2.7.1
heapdict==1.0.0
html5lib==1.0.1
idna==2.6
imageio==2.3.0
imagesize==1.0.0
importlib-metadata==0.19
ipdb==0.12.2
ipykernel==4.8.2
ipython==6.4.0
ipython-genutils==0.2.0
ipywidgets==7.2.1
isort==4.3.4
itsdangerous==0.24
jdcal==1.4
jedi==0.12.0
Jinja2==2.10
jsonschema==2.6.0
jupyter==1.0.0
jupyter-client==5.2.3
jupyter-console==5.2.0
jupyter-core==4.4.0
jupyterlab==0.32.1
jupyterlab-launcher==0.10.5
kiwisolver==1.0.1
kombu==4.6.4
lazy-object-proxy==1.3.1
llvmlite==0.23.1
locket==0.2.0
lxml==4.2.1
MarkupSafe==1.0
matplotlib==2.2.2
mccabe==0.6.1
mistune==0.8.3
mkl-fft==1.0.0
mkl-random==1.0.1
more-itertools==4.1.0
mpmath==1.0.0
msgpack-python==0.5.6
multipledispatch==0.5.0
mypy==0.650
mypy-extensions==0.4.1
navigator-updater==0.2.1
nbconvert==5.3.1
nbformat==4.4.0
networkx==2.1
nltk==3.3
nose==1.3.7
notebook==5.5.0
numba==0.38.0
numexpr==2.6.5
numpy==1.14.3
numpydoc==0.8.0
odo==0.5.1
olefile==0.45.1
openpyxl==2.5.3
packaging==17.1
pandas==0.23.0
pandocfilters==1.4.2
parso==0.2.0
partd==0.3.8
path.py==11.0.1
pathlib2==2.3.2
patsy==0.5.0
pep8==1.7.1
pexpect==4.5.0
pickleshare==0.7.4
Pillow==5.1.0
pkginfo==1.4.2
pluggy==0.6.0
ply==3.11
prompt-toolkit==1.0.15
psutil==5.4.5
ptyprocess==0.5.2
py==1.5.3
pycodestyle==2.4.0
pycosat==0.6.3
pycparser==2.18
pycrypto==2.6.1
pycurl==7.43.0.1
pyflakes==1.6.0
Pygments==2.2.0
pylint==1.8.4
pyodbc==4.0.23
pyOpenSSL==18.0.0
pyparsing==2.2.0
PySocks==1.6.8
pytest==3.5.1
pytest-arraydiff==0.2
pytest-astropy==0.3.0
pytest-doctestplus==0.1.3
pytest-openfiles==0.3.0
pytest-remotedata==0.2.1
python-dateutil==2.7.3
pytz==2018.4
PyWavelets==0.5.2
PyYAML==3.12
pyzmq==17.0.0
QtAwesome==0.4.4
qtconsole==4.3.1
QtPy==1.4.1
redis==2.10.6
requests==2.18.4
rope==0.10.7
ruamel-yaml==0.15.35
scikit-image==0.13.1
scikit-learn==0.19.1
scipy==1.1.0
seaborn==0.8.1
Send2Trash==1.5.0
simplegeneric==0.8.1
singledispatch==3.4.0.3
six==1.11.0
snowballstemmer==1.2.1
sortedcollections==0.6.1
sortedcontainers==1.5.10
Sphinx==1.7.4
sphinxcontrib-websupport==1.0.1
spyder==3.2.8
SQLAlchemy==1.2.7
sqlparse==0.3.0
statsmodels==0.9.0
sympy==1.1.1
tables==3.4.3
tblib==1.3.2
terminado==0.8.1
testpath==0.3.1
toolz==0.9.0
tornado==5.0.2
traitlets==4.3.2
typed-ast==1.1.0
typing==3.6.4
unicodecsv==0.14.1
urllib3==1.22
vine==1.3.0
wcwidth==0.1.7
webencodings==0.5.1
Werkzeug==0.14.1
widgetsnbextension==3.2.1
wrapt==1.10.11
xlrd==1.1.0
XlsxWriter==1.0.4
xlwings==0.11.8
xlwt==1.2.0
zict==0.1.3
zipp==0.6.0
</code></pre></div>
<p dir="auto"></p>
</details>
<h3 dir="auto">Other Dependencies</h3>

<details>
<p dir="auto">
N/A
</p>
</details>
<h2 dir="auto">Minimally Reproducible Test Case</h2>

<details>
<p dir="auto">
</p><div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content=""><pre class="notranslate"></pre></div>
<p dir="auto"></p>
</details>
<h1 dir="auto">Expected Behavior</h1>

<p dir="auto">Task executed in celery3 should not fail if fetched in celery4.</p>
<h1 dir="auto">Actual Behavior</h1>

<p dir="auto">Task executed in celery v3.1.26, but when tried to fetch the result of the task in celery v4.2.1 it throws an KEYERROR: 'task_id'</p>