spaCy: SpanGroup doesn't allow access to original spans

How to reproduce the behaviour

Use case: I use a custom entity ruler to populate doc.spans, a SpanGroup per entity label, to allow overlapping spans between different entity types. After the NER step is completed, I check for certain conditions and for some spans I change kb_id. Looks like SpanGroup class creates copies of Spans when iterating through them. So the assigned kb_id gets lost. There is no elegant solution to the problem except for iterating through each Span in a SpanGroup and create a new group each time kb_id needs to be re-assigned. There is no way to delete or replace a particular span from SpanGroup.

Here is code example:

Set up

import spacy
from spacy.tokens import Span, SpanGroup

nlp = spacy.load("en_core_web_sm")

text = "Span 1, Span 2"
doc = nlp(text)

nlp('kb_id_2') # add to the vocab
span_1 = Span(doc, 0, 2, label = "TEST", kb_id = 'kb_id_1')

Iterating through SpanGroup and re-assigning kb_id

doc.spans['TEST'] = [span_1]
for span in doc.spans['TEST'] :
    print("Before: %s" % span.kb_id_)
    span.kb_id = nlp.vocab.strings['kb_id_2']
    print("After: %s" % span.kb_id_)

Output:

Before: kb_id_1
After: kb_id_2

Now, iterate through the SpanGroup again:

for span in doc.spans['TEST'] :
    print(span, "=>", span.kb_id_)

Output (unchanged kb_id):

Span 1 => kb_id_1

Any help will be greatly appreciated.

Your Environment

• spaCy version: 3.0.6
• Platform: Darwin-20.3.0-x86_64-i386-64bit
• Python version: 3.7.9
• Pipelines: en_core_web_lg (3.0.0), en_core_web_md (3.0.0), en_core_web_sm (3.0.0)