tree dcebb8302c36da3ae6140b61d213f7be7e32a2d7
parent 2d609bfd37ae9a0877fb72d1ba0479bb04a2dad6
author Harsh Motwani <harsh.motwani@databricks.com> 1715316425 -0700
committer Dongjoon Hyun <dhyun@apple.com> 1715316425 -0700

[SPARK-48224][SQL] Disallow map keys from being of variant type

### What changes were proposed in this pull request?

This PR disallows map keys from being of variant type. Therefore, SQL statements like `select map(parse_json('{"a": 1}'), 1)`, which would work earlier, will throw an exception now.

### Why are the changes needed?

Allowing variant to be the key type of a map can result in undefined behavior as this has not been tested.

### Does this PR introduce _any_ user-facing change?

Yes, users could use variants as keys in maps earlier. However, this PR disallows this possibility.

### How was this patch tested?

Unit tests

### Was this patch authored or co-authored using generative AI tooling?

No

Closes #46516 from harshmotw-db/map_variant_key.

Authored-by: Harsh Motwani <harsh.motwani@databricks.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>