New EAV attributes not found without cleaning cache

[SuSiSonnenschein111]

Follow up to #4034 (comment) ....

it looks like getDefaultAttributes was blacklisted from tests for some reason

@davidhiendl no, there was nothing blacklisted. The tests never changes since years. (Only the tests have been updated to test against latest releases)

I updated CI to test against latest v20.10.0 release and the "errors" are gone, but not the failed tests.

My conclusion so far ...

• the "undifiened method getDefaultAttributes() for invoice, creditmemo" came from changed functionallity and has been fixed.
• the array_keys(null) is related to EAV cache and it is still not fixed ... so the behavoir changed to previous releases.

This error comes only across when you (progrmatically?) create a new attritbute and dont clear EAV cache afterwards.

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Actually the tests fails here - after creating new attributes:

        $this->createAttribute($entityTypeCode, $attributeCode, ['type'  => 'text', 'input' => 'text', 'label' => 'Test Attribute']);

        self::assertTrue($this->attributeExists($entityTypeCode, $attributeCode));

Failed asserting that false is true.

See: https://github.com/netz98/n98-magerun/blob/develop/tests/N98/Magento/Command/Eav/Attribute/RemoveCommandTest.php

I did not dig deeper yet, but it seems obvious ... before your PR attributeExists() recognized newly created attributes.

Now, it does not work anymore b/c of caching.

Simplest solution would be to "clean EAV cache" after calling Mage_Eav_Model_Entity_Setup::addAttribute(), but its used in all install/update scripts ... should we do that?

As far as i remember with some changes from @colinmollenhour (hope i am not wrong; cant find the PR) the cache is reinitialized automatically (in some cases?), so this would hurt ...

(PS: this is no n98-magerung problem! It only shows the changed behavoir)