can we raise custom error message when a constraint fails ?

[subramanian0331]

count: >5 @error( server count should be >5 )

can we create custom error to cue constraints?

[verdverm]

Not currently, unless you use the GoAPI to parse it out and present it. I think there is an open issue around supporting this, but the design space is a little more complicated.

consider:

port: int @error(port must be set)

port: >1024 @error(port must not be privileged)

(https://cuelang.org/play/?id=k5YIOKjxMhm#cue@export@cue)

Which error should be presented here?

Attributes are also stripped through references, so the error message can be lost

prod: count: >5   @error( server count should be >5 )

fleet: {
  count: prod.count
}

(https://cuelang.org/play/?id=wANF_9YPb3a#cue@export@cue)

This one is intentional because of

#A: {
	x: int @protobuf(1,int64)
	y: int @protobuf(2,int64)
}

a: {
	x: 1
	y: x // propagation issue here
}

-- output --

// would result in a conflict for indexes
a: {
	y: 1 @protobuf(1,int64) @protobuf(2,int64)
}