[FLINK-15546] Obscure error message from ScalarOperatorGens::generateCast

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 1.11.0
• Component/s: Table SQL / API
• Labels: pull-request-available
• Assignee: Zhenghua Gao
• Reporter: Rui Li
• Created: 10/Jan/20 07:02
• Updated: 11/Feb/20 04:05
• Resolved: 11/Feb/20 04:05

Description

Consider the following case:

Flink SQL> describe foo;
root
 |-- x: ROW<`f1` DOUBLE, `f2` VARCHAR(10)>


Flink SQL> insert into foo select row(1.1,'abc');
[INFO] Submitting SQL update statement to the cluster...
[ERROR] Could not execute SQL statement. Reason:
org.apache.flink.table.planner.codegen.CodeGenException: Unsupported cast from 'ROW' to 'ROW'.

Users are unlikely to figure out what goes wrong from the above error message. Something like Unsupported cast from 'ROW<DECIMAL(2,1), CHAR(3)>' to 'ROW<DOUBLE, VARCHAR(10)>' will be more helpful.

Issue Links

• relates to: FLINK-15584 Give nested data type of ROWs in ValidationException
• links to: GitHub Pull Request #11021