After activating cache_db it is no longer possible to filter by namespaces

[raffy99]

Bug report

Summary

After activating cache_db in system-settins it is no longer possible to filter the system-settings by namespaces

Step to reproduce

Activate cache_db setting then click click on "Filter by namespace"

Observed behavior

Depending on error reporting the click produces an error-alert: "Code: 0 communication failure" or just leaves the system-setting site in an unusable state.

Expected behavior

Show a list of namespaces for filtering.

Environment

MODX Revolution 3.1.0-pl (traditional), Apache/2.4.62 (Unix), PHP Version 8.2.20, 10.6.19-MariaDB

[halftrainedharry]

As far as I can tell, the processor (to load the available namespaces) runs a query like
SELECT GROUP_CONCAT(DISTINCT `settingsNamespace`.`namespace` SEPARATOR '","') AS namespaces FROM `modx_system_settings` AS `settingsNamespace`
here in the code:

revolution/core/src/Revolution/Processors/Workspace/PackageNamespace/GetList.php

Line 117 in 62b154a

$namespaces = $this->modx->getObject($settingsClass, $nsSubquery)->get('namespaces');

When cache_db is set to "Yes", MODX tries to save the result from this query to the cache as a modSystemSetting. But the primary key is missing (as it's not possible to include it in an SQL query like this) and that breaks the code.

---

The easiest solution is probably to add the third parameter ($cacheFlag) to this call of getObject(), so that the result is never cached:

$namespaces = $this->modx->getObject($settingsClass, $nsSubquery, false)->get('namespaces');

[raffy99]

Thanks for looking into this. Adding the the cacheFlag-parameter to the call solves the problem.
This bug was not in 3.0.6, which change caused the error?

[halftrainedharry]

I believe it was introduced with #16369.
It looks like a ton of code changes where made for version 3.1.0.