Cannot read data send from rust client on non anchor contract

Question

I'm doing unit test for my non anchor project and I'm trying to send transaction with data to contract. Here is the code:

#[derive(BorshDeserialize, BorshSerialize)]
    struct InitState<'a> {
        variant: &'a u8,
    }
    let param_init_state = InitState {
        variant: &4,
    };
let mut transaction = Transaction::new_with_payer(
        &[Instruction::new_with_borsh(
            program_id,
            &param_init_state,
            vec![
                AccountMeta::new(payer.pubkey(), true),
                AccountMeta::new(*state_account.key, false),
                AccountMeta::new(system_program::ID, false),
            ],
        )],
        Some(&payer.pubkey()),
    );

    transaction.sign(&[&payer], recent_blockhash);

    match banks_client.process_transaction(transaction).await {
        Ok(()) => (),
        Err(e) => panic!("{}", e),
    }

In solana tutorial, they use try_from_slice_unchecked(input)?; to read instruction data but it does not work for me. The compiler return Custom { kind: InvalidInput, error: "Unexpected length of input" } error if I use another way:

#[derive(BorshDeserialize, Debug)]
struct GachaMarketplacePayload {
    nft_contract: Pubkey, // program id,
    token_id: Pubkey,     // ATA
    price: u128,
    file_name: String,
    description: String,
    cash_back: u8,
    qty: u8,
    fee: u128,
    item_id: u128,
    variant: u8,
}
        let payload = GachaMarketplacePayload::try_from_slice(input).unwrap();

Answer 1

 #[derive(BorshDeserialize, BorshSerialize)]
 struct InitState<'a> {
     variant: &'a u8,
 }
 let param_init_state = InitState {
     variant: &4,
 };
 let mut transaction = Transaction::new_with_payer(
     &[Instruction::new_with_borsh(
         program_id,
         &param_init_state,
         vec![
             AccountMeta::new(payer.pubkey(), true),
             AccountMeta::new(*state_account.key, false),
             AccountMeta::new(system_program::ID, false),
         ],
     )],
     Some(&payer.pubkey()),
 );

 transaction.sign(&[&payer], recent_blockhash);

 match banks_client.process_transaction(transaction).await {
     Ok(()) => (),
     Err(e) => panic!("{}", e),

Answer 2

The param in the instruction have to match the payload for try_from_slice