[ARROW-11648] [Rust]: Json reader for nested dictionary arrays returns empty array instead of array of nulls

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Invalid
• Component/s: Rust
• External issue URL: https://github.com/apache/arrow/issues/27511
• Assignee: Unassigned
• Reporter: Jörn Horstmann
• Created: 16/Feb/21 19:42
• Updated: 11/Jan/23 08:21
• Resolved: 26/Apr/21 12:48

Description

 

// schema: id: Utf8, attr: List<Dictionary<Utf8>>
        let input = json!([
            {"id": "a"},
            {"id": "b"},
            {"id": "c"},
            {"id": "d"},
            {"id": "e"},
        ]);

// Results in ArrowError("InvalidArgumentError(\"all columns in a record batch must have the same length\")")

Probably related to `list_array_string_array_builder` around line 688:

if let Some(value) = row.get(col_name) { 
...
}
// no else

 

Expected: The resulting array should have a length equal to the number of rows, all nested lists should be marked as null.