Major Description
In ResolveAlterTableChanges, we have checks that make sure that positional arguments exist and are normalized around case sensitivity for ALTER TABLE ADD COLUMNS. However, we missed the case, where a column in ADD COLUMNS can depend on the position of a column that is just being added.
For example for the schema:
root:
- a: string
- b: long
The following should work:
ALTER TABLE ... ADD COLUMNS (x int AFTER a, y int AFTER x)
Currently, the above statement will throw an error saying that AFTER x cannot be resolved, because x doesn't exist yet.