The types defined in the errdefs package do not
satisfy the `error` interface, because they do not
implement `Error()`.
Instead of returning the matched interface, return
the original error.
When matching _multiple_ interfaces/types, Golang doesn't complain:
func getImplementer(err error) error {
switch e := err.(type) {
case
ErrNotFound,
ErrInvalidParameter:
return e
default:
return err
}
}
But matching a single interface/type:
func getImplementer(err error) error {
switch e := err.(type) {
case
ErrNotFound:
return e
default:
return err
}
}
Produces an error:
cannot use e (type ErrNotFound) as type error in return argument: ErrNotFound does not implement error (missing Error method)
Return the original `err` instead of the matched interface/type instead.
Also added some additional tests
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
