Array flip errors when books are not part of a book hierarchy

This seems to be related to using this module in conjunction with the Book module. Still looking into the issue and will likely come back with a patch for the problem.

From what I've found so far, the problem exists when a content type is enabled to be included in a book, but a node is not actually added to a book. I'm going to strip down my version of Drupal so I only have the bare minimum of modules installed so I can ensure no other modules are contributing to the error.

From what I've found so far is that within the _taxonomy_deep_index_collect function the field name: "book_ancestors" is being passed in with a type of "list<node>". When checking the value of that field in _taxonomy_deep_index_wrapper_check the $value variable contains an array with [0]=NULL. I'm thinking this is the source of the array flip problem. Array flip cannot flip the 0 and NULL values. I think entity_load IS being called, it just isn't direct. It's called when this function is performed: $result[] = $field->tid->value(); and possibly also here: $value = $entity_wrapper->value();

I can circumvent the problem by adding "list<node>" to the type of excluded entity types, but that doesn't feel quite right (which is why I haven't posted a patch with that solution yet). I'm going to spend a little more time on it today and if I don't find a better solution, that will be what I do in a patch for now. But first I'd like to try a few more things first.

To recreate

Enable "Book" module
Add content of type "Book"
Make sure Book Outline says "Not in book" (default)
publish/save
You should see the warning message right after you save.

This will actually happen on all content types, regardless of if they are enabled to be used in a book outline or not.

Another test path:
Edit that same node (or create a new one) and this time select "create a new book" on the Book Outline tab
publish/save
Notice the error goes away

Attached patch adds list<node> to the list of exclude_types.

I'm not sure this is the BEST solution for the issue, but this works. Hopefully someone can review and see if there is a better way to tackle this. (Thanks in advance!)

Awesome, thank you for taking the time to look into this more and moving it over to the correct project page. I'll give your patch a try and will let you know if I see anything strange pop up as a result.

I wish I was more knowledgeable on the core entity system so I could suggest the best approach! Maybe someone else will chime in with some thoughts?

I was hoping someone else might be able to chime in on this issue. Anyone else have some information they could add?

THANKS in advance!

jmouse888,
I can confirm that your patch makes the error go away, but I can't claim to know enough about the inner workings of entity to know if this is the right approach or not. I appreciate another set of eyes taking a look at this though, thank you!

I'm totally stuck on this issue still. My old patch for this problem no longer applies to the newest dev version of taxonomy deep index. The file jmouse88 created no longer applies to the dev version of entity, and the patch applied on this other core page https://www.drupal.org/node/2487462 contains debug statements that I can't use either. ACK! Help???!

izmeez ~ I think the issue is a tangled web. Some think it's Entity APIs issue, some think it's Core's issue, others think it's an individual module problem. However none of the issues have been solved or declared as the "main problem".

I'm hoping a solution will shake out somewhere.

+1 for committing patch #13.

I was trying the most recent patch (#19) which I now see is the incorrect one to use. #13 applied properly and is working. Thanks znerol!!