<h1 dir="auto">Checklist</h1>

<ul class="contains-task-list">
<li>[ x] 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"> This has already been asked to the <a href="https://groups.google.com/forum/#!forum/celery-users" rel="nofollow">discussion group</a> first.</li>
<li>[x ] 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>[x ] 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"> 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>
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"> 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"> 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"> 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"> 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"> 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>:</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="software -&gt; celery:4.4.2 (cliffs) kombu:4.6.8 py:3.7.5
            billiard:3.6.3.0 py-amqp:2.5.2
platform -&gt; system:Darwin arch:64bit
            kernel version:18.7.0 imp:CPython
loader   -&gt; celery.loaders.default.Loader
settings -&gt; transport:amqp results:disabled"><pre class="notranslate"><code class="notranslate">software -&gt; celery:4.4.2 (cliffs) kombu:4.6.8 py:3.7.5
            billiard:3.6.3.0 py-amqp:2.5.2
platform -&gt; system:Darwin arch:64bit
            kernel version:18.7.0 imp:CPython
loader   -&gt; celery.loaders.default.Loader
settings -&gt; transport:amqp results:disabled
</code></pre></div>
<p dir="auto"></p>
</details>
<h1 dir="auto">Steps to Reproduce</h1>
<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=""><pre class="notranslate"><code class="notranslate"></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">Backend: file system<br>
steriliser: pickle</p>
<p dir="auto">Scenario: Define a group and retrieve the result, for instance, group([add.s(1,2), add.s(3,4)])().get()<br>
This should give the correct result of two adding calculation</p>
<h1 dir="auto">Actual Behavior</h1>

<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
venv3/lib/python3.7/site-packages/celery/result.py:229: in get
    on_message=on_message,
venv3/lib/python3.7/site-packages/celery/backends/base.py:579: in wait_for_pending
    no_ack=no_ack,
venv3/lib/python3.7/site-packages/celery/backends/base.py:606: in wait_for
    meta = self.get_task_meta(task_id)
venv3/lib/python3.7/site-packages/celery/backends/base.py:457: in get_task_meta
    meta = self._get_task_meta_for(task_id)
venv3/lib/python3.7/site-packages/celery/backends/base.py:791: in _get_task_meta_for
    return self.decode_result(meta)
venv3/lib/python3.7/site-packages/celery/backends/base.py:322: in decode_result
    return self.meta_from_decoded(self.decode(payload))
venv3/lib/python3.7/site-packages/celery/backends/base.py:333: in decode
    accept=self.accept)
venv3/lib/python3.7/site-packages/kombu/serialization.py:264: in loads
    return decode(data)
/usr/local/Cellar/python/3.7.5/Frameworks/Python.framework/Versions/3.7/lib/python3.7/contextlib.py:130: in __exit__
    self.gen.throw(type, value, traceback)
venv3/lib/python3.7/site-packages/kombu/serialization.py:54: in _reraise_errors
    reraise(wrapper, wrapper(exc), sys.exc_info()[2])
venv3/lib/python3.7/site-packages/vine/five.py:194: in reraise
    raise value.with_traceback(tb)
venv3/lib/python3.7/site-packages/kombu/serialization.py:50: in _reraise_errors
    yield
venv3/lib/python3.7/site-packages/kombu/serialization.py:264: in loads
    return decode(data)
venv3/lib/python3.7/site-packages/kombu/serialization.py:338: in unpickle
    return pickle_loads(str_to_bytes(s))
venv3/lib/python3.7/site-packages/kombu/serialization.py:59: in pickle_loads
    return load(BytesIO(s))
venv3/lib/python3.7/site-packages/celery/backends/base.py:69: in unpickle_backend
    return cls(*args, app=current_app._get_current_object(), **kwargs)
venv3/lib/python3.7/site-packages/celery/backends/filesystem.py:53: in __init__
    path = self._find_path(url)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = &lt;celery.backends.filesystem.FilesystemBackend object at 0x10b2c7c90&gt;, url = None

    def _find_path(self, url):
        if not url:
&gt;           raise ImproperlyConfigured(E_NO_PATH_SET)
E           kombu.exceptions.DecodeError: You need to configure a path for the file-system backend

venv3/lib/python3.7/site-packages/celery/backends/filesystem.py:77: DecodeError"><pre class="notranslate"><code class="notranslate">
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
venv3/lib/python3.7/site-packages/celery/result.py:229: in get
    on_message=on_message,
venv3/lib/python3.7/site-packages/celery/backends/base.py:579: in wait_for_pending
    no_ack=no_ack,
venv3/lib/python3.7/site-packages/celery/backends/base.py:606: in wait_for
    meta = self.get_task_meta(task_id)
venv3/lib/python3.7/site-packages/celery/backends/base.py:457: in get_task_meta
    meta = self._get_task_meta_for(task_id)
venv3/lib/python3.7/site-packages/celery/backends/base.py:791: in _get_task_meta_for
    return self.decode_result(meta)
venv3/lib/python3.7/site-packages/celery/backends/base.py:322: in decode_result
    return self.meta_from_decoded(self.decode(payload))
venv3/lib/python3.7/site-packages/celery/backends/base.py:333: in decode
    accept=self.accept)
venv3/lib/python3.7/site-packages/kombu/serialization.py:264: in loads
    return decode(data)
/usr/local/Cellar/python/3.7.5/Frameworks/Python.framework/Versions/3.7/lib/python3.7/contextlib.py:130: in __exit__
    self.gen.throw(type, value, traceback)
venv3/lib/python3.7/site-packages/kombu/serialization.py:54: in _reraise_errors
    reraise(wrapper, wrapper(exc), sys.exc_info()[2])
venv3/lib/python3.7/site-packages/vine/five.py:194: in reraise
    raise value.with_traceback(tb)
venv3/lib/python3.7/site-packages/kombu/serialization.py:50: in _reraise_errors
    yield
venv3/lib/python3.7/site-packages/kombu/serialization.py:264: in loads
    return decode(data)
venv3/lib/python3.7/site-packages/kombu/serialization.py:338: in unpickle
    return pickle_loads(str_to_bytes(s))
venv3/lib/python3.7/site-packages/kombu/serialization.py:59: in pickle_loads
    return load(BytesIO(s))
venv3/lib/python3.7/site-packages/celery/backends/base.py:69: in unpickle_backend
    return cls(*args, app=current_app._get_current_object(), **kwargs)
venv3/lib/python3.7/site-packages/celery/backends/filesystem.py:53: in __init__
    path = self._find_path(url)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = &lt;celery.backends.filesystem.FilesystemBackend object at 0x10b2c7c90&gt;, url = None

    def _find_path(self, url):
        if not url:
&gt;           raise ImproperlyConfigured(E_NO_PATH_SET)
E           kombu.exceptions.DecodeError: You need to configure a path for the file-system backend

venv3/lib/python3.7/site-packages/celery/backends/filesystem.py:77: DecodeError
</code></pre></div>
<h1 dir="auto">Solution</h1>
<p dir="auto">FilesystemBackend class defined in <a href="https://github.com/celery/celery/blob/master/celery/backends/filesystem.py#L34">https://github.com/celery/celery/blob/master/celery/backends/filesystem.py#L34</a>, misses <code class="notranslate">__reduce__</code> method to pickle the instance properly. The following example would make it work.</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="def __reduce__(self, args=(), kwargs={}):
    kwargs.update(
        dict(url=self.url))
    return super(FilesystemBackend, self).__reduce__(args, kwargs)"><pre class="notranslate"><code class="notranslate">def __reduce__(self, args=(), kwargs={}):
    kwargs.update(
        dict(url=self.url))
    return super(FilesystemBackend, self).__reduce__(args, kwargs)
</code></pre></div>
<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 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=""> This has already been asked to the <a href="https://groups.google.com/forum/#!forum/celery-users" rel="nofollow">discussion group</a> first.</li>
<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" 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<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" checked=""> 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>
<h2 dir="auto"><a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="272093092" data-permission-text="Title is private" data-url="https://github.com/celery/celery/issues/4371" data-hovercard-type="issue" data-hovercard-url="/celery/celery/issues/4371/hovercard" href="https://github.com/celery/celery/issues/4371">#4371</a></h2>
<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>: 4.3.0 , 4.4.2</p>

<details>
<summary><b><code class="notranslate">celery report</code> Output:</b></summary>
<p dir="auto">
</p><p dir="auto">software -&gt; celery:4.3.0 (rhubarb) kombu:4.6.8 py:3.7.0<br>
billiard:3.6.3.0 py-amqp:2.5.2<br>
platform -&gt; system:Linux arch:64bit<br>
kernel version:4.15.0-91-generic imp:CPython<br>
loader   -&gt; celery.loaders.app.AppLoader<br>
settings -&gt; transport:amqp results:disabled</p>
<p dir="auto">broker_url: 'amqp://guest:********<a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/localhost/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/localhost">@localhost</a>:5672//'</p>
<p dir="auto"></p>
</details>
<h1 dir="auto">Steps to Reproduce</h1>
<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><p dir="auto">aioprocessing==1.0.1<br>
alabaster==0.7.12<br>
alembic==1.2.1<br>
amqp==2.5.2<br>
aniso8601==6.0.0<br>
astroid==2.3.3<br>
astropy==3.2.3<br>
atomicwrites==1.3.0<br>
attrs==19.3.0<br>
auto-sklearn==0.5.2<br>
Babel==2.7.0<br>
backcall==0.1.0<br>
backports.csv==1.0.7<br>
billiard==3.6.3.0<br>
bleach==3.1.0<br>
boto3==1.9.160<br>
botocore==1.12.160<br>
catboost==0.14.2<br>
celery==4.3.0<br>
celery-progress==0.0.3<br>
certifi==2019.11.28<br>
cffi==1.14.0<br>
chardet==3.0.4<br>
Click==7.0<br>
cloudpickle==1.1.1<br>
config==0.4.2<br>
configparser==3.7.4<br>
ConfigSpace==0.4.7<br>
confuse==1.0.0<br>
coreapi==2.3.3<br>
coreschema==0.0.4<br>
coverage==4.5.4<br>
cycler==0.10.0<br>
Cython==0.29.16<br>
databricks-cli==0.9.0<br>
debug==0.3.2<br>
decorator==4.4.1<br>
defusedxml==0.6.0<br>
diff-match-patch==20181111<br>
dill==0.2.9<br>
Django==2.2.2<br>
django-cors-headers==3.0.2<br>
django-dbconn-retry==0.1.5<br>
django-import-export==1.2.0<br>
django-keycloak==0.1.1<br>
django-rest-framework==0.1.0<br>
django-user==0.2.1<br>
djangorestframework==3.9.4<br>
docker==4.0.1<br>
docutils==0.14<br>
drf-yasg==1.16.0<br>
ds-lime==0.1.1.27<br>
ecdsa==0.13.2<br>
eli5==0.10.1<br>
entrypoints==0.3<br>
enum34==1.1.6<br>
et-xmlfile==1.0.1<br>
fastparquet==0.3.2<br>
Flask==1.0.3<br>
future==0.17.1<br>
gitdb2==2.0.5<br>
GitPython==2.1.11<br>
gorilla==0.3.0<br>
GPy==1.9.9<br>
GPyOpt==1.2.5<br>
graphene==2.1.7<br>
graphene-django==2.5.0<br>
graphene-file-upload==1.2.2<br>
graphql-core==2.2.1<br>
graphql-relay==2.0.0<br>
graphviz==0.11<br>
gunicorn==19.9.0<br>
h5py==2.10.0<br>
hpbandster==0.7.4<br>
htmlmin==0.1.12<br>
idna==2.8<br>
imageio==2.5.0<br>
imagesize==1.1.0<br>
importlib-metadata==0.20<br>
inflection==0.3.1<br>
ipdb==0.13.2<br>
ipython==7.13.0<br>
ipython-genutils==0.2.0<br>
isort==4.3.21<br>
itsdangerous==1.1.0<br>
itypes==1.1.0<br>
jdcal==1.4.1<br>
jedi==0.16.0<br>
Jinja2==2.10.1<br>
jmespath==0.9.4<br>
joblib==0.13.2<br>
jsonschema==3.0.1<br>
jupyter-client==5.3.4<br>
jupyter-core==4.6.1<br>
Keras==2.3.1<br>
Keras-Applications==1.0.8<br>
Keras-Preprocessing==1.1.0<br>
kiwisolver==1.1.0<br>
kombu==4.6.8<br>
lazy-import==0.2.2<br>
lazy-object-proxy==1.4.3<br>
liac-arff==2.4.0<br>
lightgbm==2.2.3<br>
lime==0.1.1.34<br>
llvmlite==0.29.0<br>
lockfile==0.12.2<br>
Mako==1.1.0<br>
MarkupSafe==1.1.1<br>
matplotlib==3.1.0<br>
mccabe==0.6.1<br>
memory-profiler==0.55.0<br>
missingno==0.4.2<br>
mistune==0.8.4<br>
mleap==0.8.1<br>
mlflow==1.2.0<br>
mock==3.0.5<br>
more-itertools==8.2.0<br>
multiprocess==0.70.7<br>
nbconvert==5.6.1<br>
nbformat==4.4.0<br>
nest-asyncio==1.2.3<br>
netifaces==0.10.9<br>
networkx==2.3<br>
nose==1.3.7<br>
nose-exclude==0.5.0<br>
numba==0.45.1<br>
numpy==1.16.4<br>
objgraph==3.4.1<br>
odfpy==1.4.0<br>
openpyxl==2.6.2<br>
packaging==19.0<br>
pandas==0.24.2<br>
pandas-profiling==2.3.0<br>
pandocfilters==1.4.2<br>
paramz==0.9.5<br>
parso==0.6.0<br>
patsy==0.5.1<br>
PDPbox==0.2.0<br>
pexpect==4.8.0<br>
phik==0.9.8<br>
pickleshare==0.7.5<br>
Pillow==6.0.0<br>
plotly==3.10.0<br>
pluggy==0.12.0<br>
prometheus-client==0.7.1<br>
promise==2.2.1<br>
prompt-toolkit==3.0.4<br>
protobuf==3.8.0<br>
psutil==5.6.2<br>
psycopg2==2.7.5<br>
ptyprocess==0.6.0<br>
py==1.8.0<br>
py4j==0.10.7<br>
pyarrow==0.14.1<br>
pyasn1==0.4.5<br>
pycparser==2.20<br>
pydot==1.4.1<br>
pyfiglet==0.8.post1<br>
Pygments==2.4.2<br>
PyHive==0.6.1<br>
pylint==2.4.3<br>
Pympler==0.7<br>
pynisher==0.5.0<br>
pyparsing==2.4.0<br>
pyrfr==0.8.0<br>
Pyro4==4.77<br>
pyrsistent==0.15.3<br>
pysasl==0.5.0<br>
pyspark==2.4.3<br>
pytest==5.1.2<br>
pytest-cov==2.7.1<br>
pytest-django==3.5.1<br>
pytest-mock==1.10.4<br>
pytest-pylint==0.14.1<br>
python-dateutil==2.8.0<br>
python-editor==1.0.4<br>
python-jose==3.0.1<br>
python-keycloak-client==0.2.2<br>
pytz==2019.1<br>
PyWavelets==1.0.3<br>
PyYAML==5.1.1<br>
pyzmq==18.1.1<br>
querystring-parser==1.2.3<br>
rabbitmq==0.2.0<br>
requests==2.22.0<br>
retrying==1.3.3<br>
rsa==4.0<br>
ruamel.yaml==0.15.97<br>
Rx==1.6.1<br>
s3transfer==0.2.0<br>
sasl==0.2.1<br>
scikit-image==0.15.0<br>
scikit-learn==0.19.2<br>
scipy==1.3.0<br>
seaborn==0.9.0<br>
see==1.4.1<br>
Send2Trash==1.5.0<br>
serpent==1.28<br>
simplejson==3.16.0<br>
singledispatch==3.4.0.3<br>
six==1.14.0<br>
skater==1.0.4<br>
smac==0.8.0<br>
smmap2==2.0.5<br>
snowballstemmer==1.2.1<br>
sobol-seq==0.1.2<br>
spark-celery==0.1.1<br>
Sphinx==2.1.0<br>
sphinx-rtd-theme==0.4.3<br>
sphinxcontrib-applehelp==1.0.1<br>
sphinxcontrib-devhelp==1.0.1<br>
sphinxcontrib-htmlhelp==1.0.2<br>
sphinxcontrib-jsmath==1.0.1<br>
sphinxcontrib-qthelp==1.0.2<br>
sphinxcontrib-serializinghtml==1.1.3<br>
SQLAlchemy==1.3.8<br>
sqlparse==0.3.0<br>
statsmodels==0.10.2<br>
tablib==0.13.0<br>
tabulate==0.8.3<br>
testpath==0.4.4<br>
thrift==0.11.0<br>
thrift-sasl==0.3.0<br>
tornado==6.0.3<br>
traitlets==4.3.2<br>
typed-ast==1.4.0<br>
typing==3.6.6<br>
uritemplate==3.0.0<br>
urllib3==1.25.3<br>
vine==1.3.0<br>
wcwidth==0.1.7<br>
webencodings==0.5.1<br>
websocket-client==0.56.0<br>
Werkzeug==0.15.4<br>
wrapt==1.11.2<br>
xgboost==0.90<br>
xlrd==1.2.0<br>
xlwt==1.3.0<br>
yellowbrick==0.9.1<br>
zipp==0.6.0</p>
<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">
1. Write a task that causes an error that does not correspond to BaseExeption.
:
</p><p dir="auto">def foo():</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content=" process = psutil.Process(os.getpid())
 print(f'foo process mem info{process.memory_full_info()}')
 dummy = numpy.array(numpy.random.randint(100, 200, 300000000))
 print(dummy.nbytes)
 idx = 0
 while idx &lt; 2:
     time.sleep(1)
     idx = idx + 1
raise ValueError"><pre class="notranslate"><code class="notranslate"> process = psutil.Process(os.getpid())
 print(f'foo process mem info{process.memory_full_info()}')
 dummy = numpy.array(numpy.random.randint(100, 200, 300000000))
 print(dummy.nbytes)
 idx = 0
 while idx &lt; 2:
     time.sleep(1)
     idx = idx + 1
raise ValueError
</code></pre></div>
<ol start="2" dir="auto">
<li>Run celery in prefork mode. Set the work volume of each worker pool to 2 or more.</li>
<li>Keep trying foo.delay()</li>
</ol>
<p dir="auto"></p>
</details>
<h1 dir="auto">Expected Behavior</h1>

<p dir="auto">Resource release after appropriate handling of exceptions</p>
<h1 dir="auto">Actual Behavior</h1>

<p dir="auto">foo.delay()<br>
foo process mem infopfullmem(rss=35368960, vms=384946176, shared=4370432, text=2338816, lib=0, data=300494848, dirty=0, uss=9674752, pss=21053440, swap=0)</p>
<p dir="auto">foo process mem infopfullmem(rss=2437492736, vms=2785394688, shared=5931008, text=2338816, lib=0, data=2700943360, dirty=0, uss=2410758144, pss=2422296576, swap=0)</p>
<p dir="auto">foo process mem infopfullmem(rss=4837507072, vms=5185384448, shared=5922816, text=2338816, lib=0, data=5100933120, dirty=0, uss=4810747904, pss=4822307840, swap=0)</p>
<p dir="auto">Memory builds up continuously</p>