<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"> 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" 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"> 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" 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>
<ul dir="auto">
<li>None</li>
</ul>
<h4 dir="auto">Possible Duplicates</h4>
<ul dir="auto">
<li>Subsequent groups within a chain fail <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="188895674" data-permission-text="Title is private" data-url="https://github.com/celery/celery/issues/3585" data-hovercard-type="issue" data-hovercard-url="/celery/celery/issues/3585/hovercard" href="https://github.com/celery/celery/issues/3585">#3585</a></li>
<li>Consecutive groups in chain fails <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="335308077" data-permission-text="Title is private" data-url="https://github.com/celery/celery/issues/4848" data-hovercard-type="issue" data-hovercard-url="/celery/celery/issues/4848/hovercard" href="https://github.com/celery/celery/issues/4848">#4848</a></li>
<li>task/group chains fails in some scenarios <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="433754701" data-permission-text="Title is private" data-url="https://github.com/celery/celery/issues/5467" data-hovercard-type="issue" data-hovercard-url="/celery/celery/issues/5467/hovercard" href="https://github.com/celery/celery/issues/5467">#5467</a></li>
</ul>
<h2 dir="auto">Environment &amp; Settings</h2>

<p dir="auto"><strong>Celery version</strong>: 4.3.0</p>

<details>
<summary><b><code class="notranslate">celery report</code> Output:
<p dir="auto">software -&gt; celery:4.3.0 (rhubarb) kombu:4.5.0 py:3.5.3<br>
billiard:3.6.0.0 redis:3.2.1<br>
platform -&gt; system:Linux arch:64bit<br>
kernel version:4.19.32-1-MANJARO imp:CPython<br>
loader   -&gt; celery.loaders.app.AppLoader<br>
settings -&gt; transport:redis results:redis://redis:6379/1</p>
<p dir="auto">broker_url: redis://redis:6379/1<br>
result_backend: redis://redis:6379/1</p>
</b><p dir="auto"><b></b></p></summary><p dir="auto"></p>
<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>
<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="from celery import  group, chain
from tasks import task as t

# failing sequence
task = group([ t.si(),t.si(), chain( t.si(), group([ t.si(), t.si()]))])

# working sequence
task = group([ t.si(),t.si(), chain( t.si(), group([ t.si(), t.si()]), t.si())])

async_result = task.apply_async()
result = async_result.get()

"><pre class="notranslate"><span class="pl-k">from</span> <span class="pl-s1">celery</span> <span class="pl-k">import</span>  <span class="pl-s1">group</span>, <span class="pl-s1">chain</span>
<span class="pl-k">from</span> <span class="pl-s1">tasks</span> <span class="pl-k">import</span> <span class="pl-s1">task</span> <span class="pl-k">as</span> <span class="pl-s1">t</span>

<span class="pl-c"># failing sequence</span>
<span class="pl-s1">task</span> <span class="pl-c1">=</span> <span class="pl-en">group</span>([ <span class="pl-s1">t</span>.<span class="pl-en">si</span>(),<span class="pl-s1">t</span>.<span class="pl-en">si</span>(), <span class="pl-en">chain</span>( <span class="pl-s1">t</span>.<span class="pl-en">si</span>(), <span class="pl-en">group</span>([ <span class="pl-s1">t</span>.<span class="pl-en">si</span>(), <span class="pl-s1">t</span>.<span class="pl-en">si</span>()]))])

<span class="pl-c"># working sequence</span>
<span class="pl-s1">task</span> <span class="pl-c1">=</span> <span class="pl-en">group</span>([ <span class="pl-s1">t</span>.<span class="pl-en">si</span>(),<span class="pl-s1">t</span>.<span class="pl-en">si</span>(), <span class="pl-en">chain</span>( <span class="pl-s1">t</span>.<span class="pl-en">si</span>(), <span class="pl-en">group</span>([ <span class="pl-s1">t</span>.<span class="pl-en">si</span>(), <span class="pl-s1">t</span>.<span class="pl-en">si</span>()]), <span class="pl-s1">t</span>.<span class="pl-en">si</span>())])

<span class="pl-s1">async_result</span> <span class="pl-c1">=</span> <span class="pl-s1">task</span>.<span class="pl-en">apply_async</span>()
<span class="pl-s1">result</span> <span class="pl-c1">=</span> <span class="pl-s1">async_result</span>.<span class="pl-en">get</span>()
</pre></div>
<p dir="auto"></p>
</details>
<h1 dir="auto">Expected Behavior</h1>
<p dir="auto">Calling <code class="notranslate">get</code> return group result.</p>
<h1 dir="auto">Actual Behavior</h1>

<p dir="auto">All task finish success but calling <code class="notranslate">.get()</code> fail with traceback:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="Traceback (most recent call last):
  File &quot;/my_app.py&quot;, line 111, in add_to_queue
    result = async_result.get()
  File &quot;/root/.cache/pypoetry/virtualenvs/my_app/lib/python3.7/site-packages/celery/result.py&quot;, line 697, in get
    on_interval=on_interval,
  File &quot;/root/.cache/pypoetry/virtualenvs/my_app/lib/python3.7/site-packages/celery/result.py&quot;, line 815, in join_native
    on_message, on_interval):
  File &quot;/root/.cache/pypoetry/virtualenvs/my_app/lib/python3.7/site-packages/celery/backends/asynchronous.py&quot;, line 137, in iter_native
    if node._cache:
AttributeError: 'GroupResult' object has no attribute '_cache'
"><pre class="notranslate"><code class="notranslate">Traceback (most recent call last):
  File "/my_app.py", line 111, in add_to_queue
    result = async_result.get()
  File "/root/.cache/pypoetry/virtualenvs/my_app/lib/python3.7/site-packages/celery/result.py", line 697, in get
    on_interval=on_interval,
  File "/root/.cache/pypoetry/virtualenvs/my_app/lib/python3.7/site-packages/celery/result.py", line 815, in join_native
    on_message, on_interval):
  File "/root/.cache/pypoetry/virtualenvs/my_app/lib/python3.7/site-packages/celery/backends/asynchronous.py", line 137, in iter_native
    if node._cache:
AttributeError: 'GroupResult' object has no attribute '_cache'

</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 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>None</li>
</ul>
<h4 dir="auto">Possible Duplicates</h4>
<ul dir="auto">
<li>None</li>
</ul>
<h1 dir="auto">Description</h1>
<p dir="auto">Did you all notice: <a href="http://celeryproject.org/" rel="nofollow">http://celeryproject.org/</a> is not available?<br>
This docs domain DO work: <a href="https://docs.celeryq.dev/en/stable/" rel="nofollow">https://docs.celeryq.dev/en/stable/</a><br>
I guess the first one is important because it is the website google indexes -&gt; you can reach it from google.</p>
<h1 dir="auto">Suggestions</h1>
<p dir="auto">(:</p>