apache / apache/datafusion

Write `Signature` method for list datatypes.

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#6,559 1 comment 0 reactions 0 assignees View on GitHub
enhancement
Dominant language
Rust
Stars
9.3k
Forks
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Avg merge
3d 7h
Merged PRs (30d)
344

Description

### Is your feature request related to a problem or challenge?

As stated in https://github.com/apache/arrow-datafusion/pull/6384, new array functions must only accept special types, including list. The main problem is that it is necessary to check the data types for each list (also nested lists).

### Describe the solution you'd like

I think it would be better to implement a recursive algorithm for checking all data types of each list item.
New `Signature` method should accept an array of the specific datatypes (like `ARRAY_DATATYPES`).

### Describe alternatives you've considered

_No response_

### Additional context

Simillar Issues:
https://github.com/apache/arrow-datafusion/issues/6119
https://github.com/apache/arrow-datafusion/issues/6075

Simillar PR:
https://github.com/apache/arrow-datafusion/pull/6384

Contributor guide

Open the contributing guide

Research direction

Start by reading the linked pull request 6384 and related issues 6119 and 6075 to understand the existing Signature behavior and special-type checks. Trace how ARRAY_DATATYPES is used and determine the expected recursive handling of nested lists; done means list datatypes at every nesting level can be validated against the specified types.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
databases
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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