EntityReferenceEntityFormatter's $recursive_render_id only looks at one parent which causes false positives on batch processes

Latest update

EntityReferenceEntityFormatter.php uses $recursive_render_id key for incrementing to detect recursion, but the key only uses the end of the node reference chain. This leads to false positives on batch processes that edit nodes whose reference chains end the same.

Recursive_render_id key is in the form of "node-[content-type]-field_[reference-field-name]-[nid-of-node-that-references]-node-[last-node's-nid-that-is-referenced]". For example "node-unit-field_unit_ref-60404378-node-60404377"

However if I have a chain of nodes and I batch process the a[n] nodes (below)..

1. a1->b->c->d
2. a2->b->c->d
3. ...
4. a21->b->c->d

.., then the recursion detection increments the end of reference chains: "c->d" and calls a false positive, when it reaches above 20 items.

As there is no recursion in any one node chain (while batch editing the a[n] nodes), this is a false positive. EntityReferenceEntityFormatter's $recursive_render_id should use the whole reference chain as an increment key so it doesn't detect false positives on batch processes.

Feel free not to read the rest of the description, as I wrote it in the first stages of debugging:

Update

It seems to me that when you have a "deep rabbit hole" of references and batch process them (even without Feeds - with VBO), then recursion detection thinks it is one render and prints an error.

However no real recursion anywhere - every reference chain of nodes is unique and no node occurs more than once in any chain.

I made a couple of tests and found that the problem also occurs with VBO batch process (as well as feeds) when batch processing contact nodes with this kind of reference structure:

contact -> unit_x -> unit_y -> unit_z (all chains end with unit_z)

When batch processing contacts, I get recursion errors on unit content:

Recursive rendering detected when rendering entity node: [last unit in chain: unit_z], using the .. field on the [previous unit in chain] entity. Aborting rendering.

However no problems when batch processing all of the units at once - error only occurs when batch processing contact nodes.

-- end of update --

Problem/Motivation

When updating about 480 nodes with Feeds, which use entity reference fields that all point to one certain node, then EntityReferenceEntityFormatter.php recursion protection gets tripped.

If I change the following constant in EntityReferenceEntityFormatter.php..
const RECURSIVE_RENDER_LIMIT = 20;
.. to this..
const RECURSIVE_RENDER_LIMIT = 500;
.. then everything works and nodes get updated.

Steps to reproduce

1. Create node that has entity reference field
2. Import a couple of hundred items with Feeds, all of which reference one certain node
3. After import Drupal log is filled with recursion error messages that come from EntityReferenceEntityFormatter.php

Proposed resolution

Change EntityReferenceEntityFormatter.php recursion protection so it works with Feeds.