🐛 [client] Fix update error propagation

[matthiasgeihs]

Fixes a bug where updateGeneric discarded a PeerRejectedError and replaced it with a different error.

Signed-off-by: Matthias Geihs matthias@perun.network

[manoranjith]

Suggested change

	err = errors.WithMessagef(derr,
	"progressing update failed: %v, then discarding update failed", updateErr)
	if derr == nil {
	return err
	}
	return errors.WithMessagef(updateErr, "progressing update failed, then discarding update failed", derr)

In it's current form, when derr is nil, errors.WithMessagef will also return a nil. So updateErr will be missed even if it is not nil.

Separated into two returns because, when derr is nil, the phrase "then discarding update failed" will be confusing.

[manoranjith]

@matthiasgeihs

[matthiasgeihs]

derr cannot be nil there because ; derr != nil {

[manoranjith]

Sorry, i missed that part. Then, it can be as it was before.

However, I think you may have to do errors.Messagef(updateErr.. instead of errors.Messagef(derr.. Because if only the message of updateErr is included, I think it cannot be retrieved later using errors.As.

[matthiasgeihs]

OK. Changing the ordering seemed unclean. Instead I do according to your first suggestion, don't change the error, just log derr. Please have a look.

[manoranjith]

LGTM. You will have to rebase to latest dev and then I can approve it.