consecutive invocations of entity_load_multiple in the same page request produce empty array

[argiepiano]

Function entity_load_multiple() can be used to load all entities of a custom entity type. For example if the custom entity type is called "event", then the syntax to get all event entities is entity_load_multiple('event'). The function returns an array of entity objects. This works as expected when you invoke entity_load_multiple('event') once.

The issue:
But if you invoke entity_load_multiple() more than once in the same page request for the same entity type (for example in different functions in a custom module), Backdrop returns an empty array for any invocation after the first one. This seems to be a logic issue when retrieving the entities cached after the first invocation.

To reproduce: define a custom entity type, create several entities and try to load all entities by invoking entity_load_multiple() more than once in the same page request

[argiepiano]

I wanted to clarify that, while the function entity_load_multiple is defined in core, the custom entities I'm referring to, use the method load in the controller class EntityPlusController defined by this module. That's why I created the issue here and not in Backdrop core.

[laryn]

Thanks for the report @argiepiano -- since this relates to caching I'm hoping @hosef will have a chance to look at it since he's the caching expert around here...

[argiepiano]

This issue is caused by backdrop/backdrop-issues#5440 , specifically the problem with cacheGet(). What that's fixed, this problem will go away.