When Multiple Entity Fields Map to the Same Taxonomy and Have Auto-create Enabled, Some Fields May Not Be Populated During Initial Import

It appears that when an entity maps to the same taxonomy from several different fields, and the Feeds importer is configured to auto-create terms, some of the reference fields might not be populated if they contain the same value in the source data.

Steps to Reproduce

1. Create a taxonomy vocabulary called "Values".
2. Create a content type called "Test".
3. Create a taxonomy reference field in the "Test" content type called "Test reference 1" that points to terms from the "Values" vocabulary.
4. Create a second taxonomy reference field in the "Test" content type called "Test reference 2" that points to terms from the "Values" vocabulary.
5. Create a CSV feeds importer that imports nodes of type "Test".
6. Map CSV field "test1" to the "Test reference 1" field, and enable "Auto create: Create the term if it doesn't exist."
7. Map CSV field "test2" to the "Test reference 2" field, and enable "Auto create: Create the term if it doesn't exist."
8. Import a CSV file with the following data:
   

   test1	test2
   Alpha	Beta
   Kiwi	Kiwi

Expected Results

Two nodes are created with the following data:

• Node 1 - Test reference 1: Alpha, Test Reference 2: Beta
• Node 2 - Test reference 1: Kiwi, Test Reference 2: Kiwi

Actual Results

Two nodes are created with the following data:

• Node 1 - Test reference 1: Alpha, Test Reference 2: Beta
• Node 2 - Test reference 1: Kiwi, Test Reference 2: (NULL)

Additional Notes

It looks like the allowed values for each taxonomy are statically cached per field in taxonomy_feeds_set_target(). This means that a snapshot of the allowed values is taken on the first row, and then that cached data is used when populating each additional row. The cached data gets updated for a particular field when a term is auto-created while populating that field, but caches for other fields that might point to the same taxonomy are not updated in the process. Only the cache for the field that created the new term is updated.

In the repro steps above, since "Kiwi" is not an allowed value in row 1, and the "Test Reference 2" field is not responsible for auto-creating the new term, it unnecessarily rejects the term during import. The value will get populated if the import is run a second time; this seems to be purely a consequence of a stale per-field cache.