InstanceDetailTests::test_instance_details_metadata fails in Django 4.2

[Akihiro Motoki]

openstack_dashboard/dashboards/project/instances/tests.py::InstanceDetailTests::test_instance_details_metadata fails with Django 4.2.

https://paste.opendev.org/show/b1shjdi1CWeXZMuPEyEY/

Failure example is found at
https://zuul.opendev.org/t/openstack/build/2b2cf8974891413091929f214a05970e/log/job-output.txt#39829-39856

[Akihiro Motoki (amotoki)]

The rendered HTMl outputs of "Metadata" section are different in Django 3.2 and 4.2.

Django 3.2
---
        <dt>someMetaLabel</dt>
        <dd>someMetaData</dd>

        <dt>some<b>html</b>label</dt>
        <dd><!--</dd>

        <dt>empty</dt>
        <dd><em>N/A</em></dd>
---

Django 4.2
---
        <dt>someMetaLabel</dt>
        <dd>someMetaData</dd>

        <dt>some<b>html</b>label</dt>
        <dd><!--</dd>

        <dt>empty</dt>
        <dd></em></dd>
---

[Akihiro Motoki (amotoki)]

Looking at the corresponing template [1], L.149 does the magic for the default value when a value is empty. I am afraid this is an undocument/unspecified behavior and it was changed in Django 4.2 (or 4.x series).
Perhaps it is better to use {% if %} clause rather than this magic.

[1] https://opendev.org/openstack/horizon/src/branch/master/openstack_dashboard/dashboards/project/instances/templates/instances/_detail_overview.html#L149-L153

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/horizon/+/899021

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/horizon/+/899021
Committed: https://opendev.org/openstack/horizon/commit/5c61331ff229b4e9e8b51c6335cd1895b90fdfa0
Submitter: "Zuul (22348)"
Branch: master

commit 5c61331ff229b4e9e8b51c6335cd1895b90fdfa0
Author: Akihiro Motoki <email address hidden>
Date: Mon Oct 23 15:36:49 2023 +0900

    Django 4.2: Adjust instance detail template

    The template for the instance detail overview uses Django template
    filters to define a default value for metadata with an empty value.
    This usage looks magic and does not work with Django 4.2.
    It looks like this is an undocumented/unspecified behavior.
    This commit changes it to use {% if %} template syntax instead of
    depending on the unspcified behavior.

    Closes-Bug: #2040129
    Change-Id: Ida5b2a721f2657347c174e386d2e023dffd64b1b

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/horizon 23.4.0 release.