Redis master replica sync delay or Disable Translations cache causes "Required parameter 'theme_dir' was not passed" error #900
Description
Preconditions (*)
1.Reproduced in clean Magento version 2.4.7-p3
2.Installing and configuring Redis master and slave
The settings file is as follows
Steps to reproduce (*)
There are two ways to reproduce:
①Redis master replica sync delay
1.Simulating master-slave delay
A.Cancel master-slave synchronization
B.Delete the db0 data from the slave database
2.Administrator user login backend
3.Create a CMS block with any content
4.Create a CMS page and associate the content of the page with the block in step 2
5.Open the editing screen for the CMS page you created in step 3
②Disable Translations cache
1.Disable Translations cache in the background page
2.Create a CMS block with any content
3.Create a CMS page and associate the content of the page with the block in step 2
4.Open the editing screen for the CMS page you created in step 3
Expected result (*)
The screen is displayed correctly and no error messages are displayed. Preview content correctly displays the contents of the CMS blocks embedded in the CMS page.
Actual result (*)
An error message appears. The contents of the CMS block embedded in the CMS page are not displayed.
Additional information
Execution log：The error message "main.ERROR: Required parameter 'theme_dir' was not passed" is displayed.
After investigating the data flow, we found that the cache is saved using the underlying Zend_Cache_Core::save method. Specifically, on line 407, the cache key is removed because the condition on line 405 is met:
if ($data !== $data2)
We suspect this is due to Redis replication lag — the data might not have been fully synced between the primary and replica at the time of the comparison. When only a single Redis primary instance is used (no replicas), this issue does not occur.
At this point, we’re unsure whether this behavior is caused by Magento or is inherent to Zend Framework’s caching logic.
Would appreciate any insights or similar findings from the community.