[Bug] BE crash when doing alter task

[morningman]

Search before asking

• I had searched in the issues and found no similar issues.

Version

trunk 61c9d11

What's Wrong?

BE crash when visiting _input_batch of rowset reader.

What You Expected?

Not crash

How to Reproduce?

If the rowset reader is not initialized successfully, the reader should not be used.

Anything Else?

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct