Related to #45543
When a field with a default value is added to a collection, the default
value becomes null after compaction instead of retaining the expected
default value.
**Root Cause**
The `appendValueAt` function in `internal/storage/arrow_util.go`
incorrectly checked if the entire arrow.Array was nil before handling
default values. This meant that default values were only applied when
the array itself was nil, not when individual field values were null
(which is the correct condition).
**Changes**
1. **Early nil check**: Added a guard at the function entry to detect
nil arrow.Array and return an error immediately, as this is an
unexpected condition that should not occur during normal operation.
2. **Refactored default value handling**: Removed the per-type nil array
checks and moved default value logic to handle individual null values
within the array (when `IsNull(idx)` returns true).
3. **Applied to all types**: Updated the logic consistently across all
builder types:
- BooleanBuilder
- Int8Builder, Int16Builder, Int32Builder, Int64Builder
- Float32Builder
- StringBuilder
- BinaryBuilder (added default value support for internal $meta json)
- ListBuilder (removed unnecessary nil check)
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Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>
e9506f1d64