Proposal - Error types

[luismoyano]

Hello @json-logic/core!

This is probably related with #18 and #36

Recently I've been working out on the errors system according to the specifications decided here and found that there's no discussions/concensus yet about which types of errors to expect. Given that the whole point of JSONLogic is to expect same behavior on every language, we also need to deliver the same error types everywhere.

Keep in mind I decided for a new proposal instead of introducing this concern as a comment in #20 because a decision had already been achieved there.

My proposal is inspired on the existing work made in datalogic-rs since there seems to be handlers for every possible scenario around JSONLogic (or at least most of it).

Error values

In order to provide useful contextual information about the errors, it would be great to deliver values about them. I believe the right format would be:

{ type: "Some error", values:[{ name: <value_name:string>, value: <value_content:any> }, #...] }

This way, users can traverse a list of values without the need to worry about unexpected or specific key names.

Error types

Subject	Type value	Possible values
Invalid operator name	Invalid operator	operator/operator_name:string
Invalid arguments for an operator	Invalid arguments	operator/operator_name:string, got/value_type:string, expected/value_type:string
Variable not found in context	Value not found	value/value_name:string
Invalid context level access	Invalid context level access	Not sure yet about this case
Type conversion/coercion error	Cast error	value/value_content:any, from/value_type:string, to/value_type:string
Arithmetic error (division by zero, overflow, etc.)	Arithmetic error	kind/event_type:string (division by zero, infinity, overflow, etc...)
Custom error for extensions	Custom	operator/operator_name:string
JSON parsing/serialization error	Parsing error	Maybe we could deliver the json's parser failure here, right away
Thrown error from throw operator	Thrown	Nothing
Invalid format string or pattern	Invalid format	Not sure about this one yet
Index out of bounds for array operations	Index out of bounds	index/index_value:number, length/length_value:number
Invalid operator configuration	Invalid configuration	Not sure about this one yet.

Would love to read your thoughts. Thanks!!

[luismoyano]

@TotalTechGeek Any opinions on this proposal?

[TotalTechGeek]

I think our preference is to define error types with the operators as we develop a comprehensive test suite for each operator.

Example here:

• https://github.com/orgs/json-logic/discussions/21

Some of these error types don't really match the behavior of how the operators are defined like: "Variable not found in context"

We find it's generally best to build bottom-up.

[luismoyano]

Understood, thanks for your time!