[ARROW-11080] [C++][Dataset] Improvements to implicit casting

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Fix Version/s: 3.0.0
• Component/s: C++
• External issue URL: https://github.com/apache/arrow/issues/26992
• Assignee: Ben Kietzman
• Reporter: Neal Richardson
• Created: 30/Dec/20 22:15
• Updated: 11/Jan/23 08:17
• Resolved: 06/Jan/21 15:46

Description

Followup to ARROW-10322. In ARROW-9187, where we started making use of more compute functions in R, we found a couple of places where implicit casts weren't being inserted where they should:

• https://github.com/apache/arrow/pull/8947/commits/843ff2a39d8a4e1c92247fb672567c0b85b4f45a#diff-79100695986bbd6a63704fe9f238ce3ae9a39ddd093b7f6b213d4a722309d20aR576 "Function multiply_checked has no kernel matching input types (scalar[double], array[int32])"
• https://github.com/apache/arrow/pull/8947/commits/843ff2a39d8a4e1c92247fb672567c0b85b4f45a#diff-79100695986bbd6a63704fe9f238ce3ae9a39ddd093b7f6b213d4a722309d20aR590 "Function add_checked has no kernel matching input types (array[double], array[int32])" because implicit casts are only applied to scalars to cast them to the type of the other argument

This may speak to a need for more rules around how inputs should be casted/promoted in different contexts.

Issue Links

• duplicates: ARROW-8919 [C++] Add "DispatchBest" APIs to compute::Function that selects a kernel that may require implicit casts to invoke