[SPARK-47907] Put removal of '!' as a synonym for 'NOT' on a keyword level under a config

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.0
• Fix Version/s: 4.0.0
• Component/s: Spark Core
• Labels: pull-request-available
• Assignee: Serge Rielau
• Reporter: Serge Rielau
• Created: 19/Apr/24 04:29
• Updated: 22/Apr/24 20:53
• Resolved: 22/Apr/24 20:53

Description

Recently we dissolved the lexer equivalence between '!' and 'NOT'.
! is a prefix operator and a synonym for NOT only in that case.
But NOT is used in many more cases in the grammar.
Given that there are a handful of known scenearios where users have exploited the undocumented loophole it's best to add a config.
Usage found so far is:

`c1 ! IN(1, 2)`
`c1 ! BETWEEN 1 AND 2`
`c1 ! LIKE 'a%'`

 But there are worse cases:
c1 IS ! NULL
CREATE TABLE T(c1 INT ! NULL)
or even
CREATE TABLE IF ! EXISTS T(c1 INT)

Issue Links

• links to: GitHub Pull Request #46138