Potential Bug: setValue does not always work for unregistered inputs

[joniaiuser]

I have this piece of code in my app

const removeFile = useCallback(
		({ _id, actionType }: { _id?: string; actionType: ContractActionType }) => {
			const newAttachmentArray =
				attachments.get(actionType)?.filter((att) => att._id !== _id) ?? [];

			setAttachments(
				produce((prev) => prev.set(actionType, newAttachmentArray))
			);
			const idx = getIndex(actionType);
			const currentData = getValues(
				`loanContractActions.${idx}` as "loanContractActions.0"
			);
			register(`loanContractActions.${idx}` as "loanContractActions.0");
			setValue(
				`loanContractActions.${idx}` as "loanContractActions.0",
				{ ...currentData, attachments: newAttachmentArray },
				{ shouldDirty: true }
			);
		},
		[attachments, setValue, getValues, setAttachments, getIndex, register]
	);

If I remove the line
register(`loanContractActions.${idx}` as "loanContractActions.0");
There will be instances where after calling router.replace(router.asPath) in nextjs, the setValue will be unable to set the value of the attachments array back to an empty array. It will work again after a hard refresh.

I have yet to do a repro in code sandbox, as I managed to fix it using register. But this is different behaviour from what is suggested in the documentation where register is only 'recommended'.

I am using version 7.12.1 react-hook-form and NextJS version 11.0.1

[bluebill1049]

Try with the next version v7.12.1-next.0 it's always a little bit harder to setValue with out register tho, consider hook form is all about inptus.

[joniaiuser]

I see. Just gave it a try. Same issue if I remove the register line. Adding it back fixes it.