issue: #43980
This commit optimizes the partial update merge logic by standardizing
nullable field representation before merge operations to avoid corner
cases during the merge process.
Key changes:
- Unify nullable field data format to FULL FORMAT before merge execution
- Add extensive unit tests for bounds checking and edge cases
The optimization ensures:
- Consistent nullable field representation across SDK and internal
- Proper handling of null values during merge operations
- Prevention of index out-of-bounds errors in vector field updates
- Better error handling and validation for partial update scenarios
This resolves issues where different nullable field formats could cause
merge failures or data corruption during partial update operations.
Signed-off-by: Wei Liu <wei.liu@zilliz.com>
18371773dd