Improve consistency and documentation on error handling in in UDFs #11618
Description
Is your feature request related to a problem or challenge?
When writing a new UDF, a developer needs to decide how to perform error management in functions that return Result, such as return_type and invoke. Looking at the existing codebase it is not obvious what are the error management best practices
Errors in return type
-
Regexp like uses an
. Is this check redundant?plan_errdata types of args do not match the expected types -
Except expects two arguments but doesn't check the length, just the type
.
Errors in invoke
In the resize function, there is a check on argument lengths in invoke which is not present in the return_type function
The same function also returns exec_err, and internal_datafusion_err
Describe the solution you'd like
As a developers of custom UDF I would like to know:
- what errors I need to check for and what are already checked by the planner (number of arguments?)
- what type of errors need to be raised in which conditions
Describe alternatives you've considered
No response
Additional context
No response