Python: fix(redis): wrap IndexDefinition prefix in list; use _get_redis_key in JSON delete

[nileshpatil6]

Summary

Two bugs in python/semantic_kernel/connectors/redis.py:

Bug 1 — IndexDefinition prefix iterates character-by-character (fixes #13894)

ensure_collection_exists passed a bare str as the prefix argument:

# before
index_definition = IndexDefinition(
    prefix=f"{self.collection_name}:", index_type=...
)

redis-py's IndexDefinition accepts an iterable of prefixes. When passed a plain string it iterates character by character, generating a PREFIX N c o l l e c t i o n ... clause instead of PREFIX 1 collection_name:. This causes the index to match nothing (or incorrectly).

# after
index_definition = IndexDefinition(
    prefix=[f"{self.collection_name}:"], index_type=...
)

Bug 2 — RedisJsonCollection._inner_delete silently no-ops (fixes #13904)

_inner_delete passed the raw caller key to json().delete():

# before
async def _inner_delete(self, keys: Sequence[str], **kwargs: Any) -> None:
    await asyncio.gather(*[self.redis_database.json().delete(key, **kwargs) for key in keys])

But _single_upsert stores keys as {collection_name}:{key} (via _get_redis_key). The delete always targeted a non-existent key and returned 0 without raising. RedisHashsetCollection._inner_delete already uses _get_redis_key correctly.

# after
async def _inner_delete(self, keys: Sequence[str], **kwargs: Any) -> None:
    await asyncio.gather(*[self.redis_database.json().delete(self._get_redis_key(key), **kwargs) for key in keys])

Testing

Both fixes are straightforward and can be verified with a live Redis instance by:

1. Creating a RedisJsonCollection, upserting a record, then deleting it and confirming it's gone.
2. Checking FT.INFO <collection_name> to confirm the PREFIX clause is 1 <collection_name>: after ensure_collection_exists.

[Copilot]

Pull request overview

This PR fixes two Redis connector bugs in the Python vector store implementation (RedisCollection / RedisJsonCollection) to ensure RediSearch indexes are created with the intended key prefix and JSON deletions target the actual stored keys.

Changes:

• Wrap IndexDefinition.prefix in a list so redis-py doesn’t iterate the prefix string character-by-character.
• Apply _get_redis_key() when deleting JSON records so deletes work when key prefixing is enabled.

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[github-actions]

Automated Code Review

Reviewers: 4 | Confidence: 94%

✓ Correctness

Both fixes are correct and well-motivated. Bug 1 wraps the IndexDefinition prefix string in a list, which is required because redis-py's IndexDefinition iterates over the prefix argument — a bare string would be iterated character-by-character. Bug 2 adds the missing _get_redis_key() call in RedisJsonCollection._inner_delete, making it consistent with RedisHashsetCollection._inner_delete (line 581) and RedisJsonCollection._inner_get (line 699), both of which already use _get_redis_key to prepend the collection name prefix.

✓ Security Reliability

Both changes are correct and well-scoped bug fixes. Fix 1 wraps the IndexDefinition prefix in a list to prevent character-by-character iteration of the string — consistent with redis-py's expected API. Fix 2 adds the missing _get_redis_key() call in RedisJsonCollection._inner_delete, making it consistent with _inner_get (line 699) and the hashset collection's _inner_delete (line 581). No security or reliability concerns are introduced by these changes.

✓ Test Coverage

Both fixes are correct and address real bugs, but neither has unit test coverage that would actually catch a regression. Bug 1 (IndexDefinition prefix as list): test_create_index mocks create_index entirely, so the IndexDefinition is constructed but never inspected — the test passes whether prefix is a string or a list. Bug 2 (JSON delete with _get_redis_key): test_delete only uses non-prefix collections (prefix_collection_name_to_key_names=False), making _get_redis_key a no-op. The fix is only meaningful with prefixing enabled, but no such test exists for delete. Compare with test_get, which does parametrize over prefix=True/False for both collection types. Both fixes should have corresponding tests that verify the corrected behavior.

✗ Design Approach

The JSON delete change follows the existing key-normalization pattern correctly, but the index-definition fix is still incomplete: it wraps the prefix in a list, yet the auto-created index prefix remains unconditional and does not match the default write path when prefix_collection_name_to_key_names is left at its default False.

Flagged Issues

• python/semantic_kernel/connectors/redis.py:281 hard-codes an index prefix of collection_name: even though both concrete collections default prefix_collection_name_to_key_names=False (redis.py:524, redis.py:652) and store keys via _get_redis_key, which returns the raw key when that flag is false (redis.py:250-253, :599, :723). The default upsert writes id1 while the index only matches test:-prefixed keys. The auto-generated index definition should derive its prefix from prefix_collection_name_to_key_names instead of always forcing collection_name:.

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Automated review by nileshpatil6's agents

[github-actions]

Missing test coverage. This fix is correct — RedisHashsetCollection._inner_delete (line 581) already uses _get_redis_key. However, the existing test_delete (test_redis_store.py:274) only uses non-prefix collections (collection_hash/collection_json), where _get_redis_key returns the key unchanged. The test passes identically with the old and new code. Please add a test with collection_with_prefix_json that asserts json().delete() receives 'test:id1', not 'id1'.

[github-actions]

Design mismatch & missing test coverage. Wrapping the prefix in a list fixes the redis-py API usage, but the index prefix is still unconditionally set to collection_name:. Both RedisHashsetCollection and RedisJsonCollection default prefix_collection_name_to_key_names=False (redis.py:524, redis.py:652), so _get_redis_key returns the raw key (redis.py:250-253). Default upsert writes id1 while the index only matches test:-prefixed keys. The prefix should be derived from prefix_collection_name_to_key_names. Additionally, test_create_index (test_redis_store.py:294) mocks create_index without inspecting its arguments — consider asserting on the mock's call_args to verify the definition was constructed with the correct prefix.