<p dir="auto"><strong>Apache Airflow version</strong>: 2.0.1</p>
<p dir="auto"><strong>Kubernetes version (if you are using kubernetes)</strong> (use <code class="notranslate">kubectl version</code>):</p>
<p dir="auto"><strong>Environment</strong>:</p>
<ul dir="auto">
<li>
<p dir="auto"><strong>Cloud provider or hardware configuration</strong>: Dell Latitude</p>
</li>
<li>
<p dir="auto"><strong>OS</strong> (e.g. from /etc/os-release): Ubuntu 20.04.2 LTS</p>
</li>
<li>
<p dir="auto"><strong>Kernel</strong> (e.g. <code class="notranslate">uname -a</code>): 5.8.0-48-generic <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="89720033" data-permission-text="Title is private" data-url="https://github.com/apache/airflow/issues/54" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/54/hovercard" href="https://github.com/apache/airflow/pull/54">#54</a>~20.04.1-Ubuntu SMP Sat Mar 20 13:40:25 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux</p>
</li>
<li>
<p dir="auto"><strong>Install tools</strong>: python 3.8.5</p>
</li>
<li>
<p dir="auto"><strong>Others</strong>: local development</p>
</li>
</ul>
<p dir="auto"><strong>What happened</strong>: When I click delete button (on UI admin panel) for the DAG, admin panel crashed</p>
<p dir="auto">Traceback (most recent call last):<br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/flask/app.py", line 2447, in wsgi_app<br>
response = self.full_dispatch_request()<br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/flask/app.py", line 1952, in full_dispatch_request<br>
rv = self.handle_user_exception(e)<br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/flask/app.py", line 1821, in handle_user_exception<br>
reraise(exc_type, exc_value, tb)<br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise<br>
raise value<br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/flask/app.py", line 1950, in full_dispatch_request<br>
rv = self.dispatch_request()<br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/flask/app.py", line 1936, in dispatch_request<br>
return self.view_functions<a href="**req.view_args">rule.endpoint</a><br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/airflow/www/auth.py", line 34, in decorated<br>
return func(*args, **kwargs)<br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/airflow/www/decorators.py", line 60, in wrapper<br>
return f(*args, **kwargs)<br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/airflow/www/views.py", line 1393, in delete<br>
delete_dag.delete_dag(dag_id)<br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/airflow/utils/session.py", line 65, in wrapper<br>
return func(*args, session=session, **kwargs)<br>
File "/home/krzysztofwrobel/.local/lib/python3.8/site-packages/airflow/api/common/experimental/delete_dag.py", line 54, in delete_dag<br>
for model in models.base.Base._decl_class_registry.values():  # noqa pylint: disable=protected-access<br>
AttributeError: type object 'Base' has no attribute '_decl_class_registry</p>

<p dir="auto"><strong>What you expected to happen</strong>: Delete DAG</p>

<p dir="auto"><strong>How to reproduce it</strong>: Try to delete dag in admin panel</p>

<p dir="auto"><strong>Anything else we need to know</strong>:</p>
<h3 dir="auto">Body</h3>
<p dir="auto">I have a kind request for all the contributors to the latest provider packages release.<br>
Could you please help us to test the RC versions of the providers?</p>
<p dir="auto">Let us know in the comment, whether the issue is addressed.</p>
<p dir="auto">Those are providers that require testing as there were some substantial changes introduced:</p>
<h2 dir="auto">Provider <a href="https://pypi.org/project/apache-airflow-providers-amazon/8.0.0rc3" rel="nofollow">amazon: 8.0.0rc3</a></h2>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> <a href="https://github.com/apache/airflow/pull/30748" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30748/hovercard">Remove deprecated "delegate_to" from GCP operators and hooks (#30748)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/shahar1/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/shahar1">@shahar1</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> <a href="https://github.com/apache/airflow/pull/30755" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30755/hovercard">take advantage of upcoming major version release to remove deprecated things (#30755)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/vandonr-amz/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/vandonr-amz">@vandonr-amz</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> <a href="https://github.com/apache/airflow/pull/30720" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30720/hovercard">add a stop operator to emr serverless (#30720)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/vandonr-amz/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/vandonr-amz">@vandonr-amz</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> <a href="https://github.com/apache/airflow/pull/30460" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30460/hovercard">SqlToS3Operator - Add feature to partition SQL table (#30460)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/utkarsharma2/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/utkarsharma2">@utkarsharma2</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> <a href="https://github.com/apache/airflow/pull/28338" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/28338/hovercard">New AWS sensor — DynamoDBValueSensor (#28338)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/mrichman/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/mrichman">@mrichman</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> <a href="https://github.com/apache/airflow/pull/30757" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30757/hovercard">Add a "force" option to emr serverless stop/delete operator (#30757)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/vandonr-amz/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/vandonr-amz">@vandonr-amz</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> <a href="https://github.com/apache/airflow/pull/30032" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30032/hovercard">Add support for deferrable operators in AMPP (#30032)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/syedahsn/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/syedahsn">@syedahsn</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> <a href="https://github.com/apache/airflow/pull/30703" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30703/hovercard">Fixed logging issue in <code class="notranslate">DynamoDBValueSensor</code> (#30703)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/mrichman/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/mrichman">@mrichman</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> <a href="https://github.com/apache/airflow/pull/30595" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30595/hovercard">DynamoDBHook - waiter_path() to consider <code class="notranslate">resource_type</code> or <code class="notranslate">client_type</code> (#30595)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/utkarsharma2/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/utkarsharma2">@utkarsharma2</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> <a href="https://github.com/apache/airflow/pull/30586" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30586/hovercard">Add ability to override waiter delay in EcsRunTaskOperator (#30586)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/vincbeck/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/vincbeck">@vincbeck</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> <a href="https://github.com/apache/airflow/pull/29522" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/29522/hovercard">Add support in AWS Batch Operator for multinode jobs (#29522)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/vandonr-amz/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/vandonr-amz">@vandonr-amz</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> <a href="https://github.com/apache/airflow/pull/30756" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30756/hovercard">AWS logs. Exit fast when 3 consecutive responses are returned from AWS Cloudwatch logs (#30756)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/vincbeck/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/vincbeck">@vincbeck</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> <a href="https://github.com/apache/airflow/pull/30868" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30868/hovercard">Fix async conn for none aws_session_token (#30868)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/pankajastro/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/pankajastro">@pankajastro</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> <a href="https://github.com/apache/airflow/pull/30774" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30774/hovercard">Remove @poke_mode_only from EmrStepSensor (#30774)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/vincbeck/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/vincbeck">@vincbeck</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> <a href="https://github.com/apache/airflow/pull/30541" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30541/hovercard">Organize Amazon provider docs index (#30541)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/eladkal/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/eladkal">@eladkal</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> <a href="https://github.com/apache/airflow/pull/30634" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30634/hovercard">Remove duplicate param docstring in EksPodOperator (#30634)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/jlaneve/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/jlaneve">@jlaneve</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox"> <a href="https://github.com/apache/airflow/pull/30844" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30844/hovercard">Update AWS EMR Cluster Link to use the new dashboard (#30844)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/dakshin-k/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/dakshin-k">@dakshin-k</a></li>
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> <a href="https://github.com/apache/airflow/pull/30874" data-hovercard-type="pull_request" data-hovercard-url="/apache/airflow/pull/30874/hovercard">Restore aiobotocore as optional dependency of amazon provider (#30874)</a>: <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/potiuk/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/potiuk">@potiuk</a></li>
</ul>
<p dir="auto">The guidelines on how to test providers can be found in</p>
<p dir="auto"><a href="https://github.com/apache/airflow/blob/main/dev/README_RELEASE_PROVIDER_PACKAGES.md#verify-by-contributors">Verify providers by contributors</a></p>

<p dir="auto">I have marked issues that were <a href="https://github.com/apache/airflow/issues/30849" data-hovercard-type="issue" data-hovercard-url="/apache/airflow/issues/30849/hovercard">tested in RC2</a> as completed.</p>
<p dir="auto">All users involved in the PRs:<br>
<a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/vincbeck/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/vincbeck">@vincbeck</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/utkarsharma2/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/utkarsharma2">@utkarsharma2</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/syedahsn/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/syedahsn">@syedahsn</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/mrichman/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/mrichman">@mrichman</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/shahar1/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/shahar1">@shahar1</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/vandonr-amz/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/vandonr-amz">@vandonr-amz</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/eladkal/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/eladkal">@eladkal</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/potiuk/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/potiuk">@potiuk</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/jlaneve/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/jlaneve">@jlaneve</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/pankajastro/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/pankajastro">@pankajastro</a> <a class="user-mention notranslate" data-hovercard-type="user" data-hovercard-url="/users/dakshin-k/hovercard" data-octo-click="hovercard-link-click" data-octo-dimensions="link_type:self" href="https://github.com/dakshin-k">@dakshin-k</a></p>
<h3 dir="auto">Committer</h3>
<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I acknowledge that I am a maintainer/committer of the Apache Airflow project.</li>
</ul>