[ARROW-246] [Java] UnionVector doesn't call allocateNew() when creating it's vectorType

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.1.0
• Component/s: Java
• External issue URL: https://github.com/apache/arrow/issues/15588
• Assignee: Abdel Hakim Deneche
• Reporter: Abdel Hakim Deneche
• Created: 01/Aug/16 19:07
• Updated: 11/Jan/23 07:07
• Resolved: 03/Aug/16 02:11

Description

UnionVector uses a UINT1Vector to store the types of every value in the vector., but it doesn't call allocateNew() on that vector and more importantly zeroVector(). When we call setSafe() the 1st time (e.g. from PromotableVector.promoteToUnion()) it will re-allocate the vector but will fail to properly set it's content to 0. This can cause various failures when we try to access the value/type stored in the vector.