ACSD-55031: Type "mixed" cannot be nullable error during compilation

The ACSD-55031 patch fixes the issue where the Type "mixed" cannot be nullable error during compilation after installing a custom extension. This patch is available when the Quality Patches Tool (QPT) 1.1.40 is installed. The patch ID is ACSD-55031. Please note that the issue was fixed in Adobe Commerce 2.4.6.

Affected products and versions

The patch is created for Adobe Commerce version:

  • Adobe Commerce (all deployment methods) 2.4.5-p4

Compatible with Adobe Commerce versions:

  • Adobe Commerce (all deployment methods) 2.4.5 - 2.4.5-p5
The patch might become applicable to other versions with new Quality Patches Tool releases. To check if the patch is compatible with your Adobe Commerce version, update the magento/quality-patches package to the latest version and check the compatibility on the Quality Patches Tool: Search for patches page. Use the patch ID as a search keyword to locate the patch.


The Type "mixed" cannot be nullable error occurs during compilation.

Steps to reproduce:

  1. Install a custom extension.
  2. Run the command bin/magento setup:di:compile.

Expected results:

No errors occur during compilation.

Actual results:

The var/log/system.log file contains the error:

report.ERROR: Type "mixed" cannot be nullable

Apply the patch

To apply individual patches, use the following links depending on your deployment method:

To learn more about Quality Patches Tool, refer to:

For info about other patches available in QPT, refer to Quality Patches Tool: Search for patches in the Quality Patches Tool guide.