Empty array flatten regression since "improve flatten performance by reducing copy"

[wader]

gojq master

$ go run cmd/gojq/main.go -n '[] | flatten'
null

gojq a1a2550~1

$ go run cmd/gojq/main.go -n '[] | flatten'
[]

I think the problem is that the new version ends up doing [] | add for [] input. Just add a special case or is there some neater way?

[itchyny]

Thanks for catch.

[wader]

👍