I'm trying to add an extension attribute to \Magento\Quote\Api\Data\TotalsInterface. My understanting is, that magento should generate getter/setter for the new attribute, but that is not happening. (i tried deleting var/generation var/cache multiple times)


<?xml version="1.0"?> 
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    <extension_attributes for="Magento\Quote\Api\Data\TotalsInterface">        
        <attribute code="custom_attribute" type="string"/>

Is my understanding correct, or is this just not possible?

The interface is instantiated using factory in Magento\Quote\Model\Cart\CartTotalRepository. Could that have an effect?

Any help would be greatly appreciated.

1 Answer 1


The getters and setters are not added to the TotalsInterface itself.

Instead they are generated in Magento\Quote\Api\Data\TotalsExtensionInterface (which you should find in var/generation) and you use it like this (for custom_attribute):

  • That is exactly what i would expect to happen. However TotalsExtensionInterface.php is never generated.
    – Langley
    Jun 3, 2016 at 13:48
  • Not at all, not even empty? Are you running in developer mode? Are other classes generated? Jun 3, 2016 at 13:58
  • I'm running developer mode. The file is not there but others are (TotalsInterfaceFactory, TotalSegmentExtension etc). getExtensionAttributes() returns null so i assume the attribute is not registered? I have no idea why that is.
    – Langley
    Jun 3, 2016 at 14:01
  • Weird, it should be there. I don't fully understand when these are generated, maybe magento.stackexchange.com/questions/93366/… is helpful in that case Jun 3, 2016 at 14:03
  • 1
    Ok thanks for your time, the information provided is correct. It is working now, but i have no idea what changed. What i did: 1, Reinstalled magento and update 2.0.5 to 2.0.7 2, ran setup:di:compile - again my extension interface is not generated 3, reformatted my extension_attributes.xml (with ide and also removed the line break) 4, ran setup:di:compile - the interface gets generated T_T Number of generated files in /Magento/Quote/Api/Data is much greater than before. (not sure if that's caused by version update)
    – Langley
    Jun 3, 2016 at 15:21

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