Bug Description

parse_partial_json contains an internal logic bug when handling incomplete JSON string values.

For inputs where a string value is truncated (e.g. missing the closing quote), the function incorrectly treats the unfinished value as an incomplete key and removes it, even though the key–value structure is already established.

This results in existing value content being dropped and replaced with null, which does not match the intended behavior of completing partial JSON. The issue is caused by incorrect internal logic that determines whether an unfinished string corresponds to an incomplete key or an incomplete value.

I plan to submit a PR to fix this logic.

Version

llama_index_core==0.14.13

Steps to Reproduce

from llama_index.core.llms.utils import parse_partial_json

result = parse_partial_json('{"key": "value') 
print(result) # got {'key': None} expected {'key': 'value'}

Relevant Logs/Tracbacks