Function verify 

pub fn verify(
    script_pubkey: &impl ScriptPubkeyExt,
    amount: Option<i64>,
    tx_to: &impl TransactionExt,
    input_index: usize,
    flags: Option<u32>,
    spent_outputs: &[impl TxOutExt],
) -> Result<(), KernelError>

Verifies a transaction input against its corresponding output script.

This function checks that the transaction input at the specified index properly satisfies the spending conditions defined by the output script. The verification process depends on the script type and the consensus rules specified by the flags.

Arguments

• script_pubkey - The output script (locking script) to verify against
• amount - The amount in satoshis of the output being spent. Required for SegWit and Taproot scripts (when VERIFY_WITNESS or VERIFY_TAPROOT flags are set). Optional for pre-SegWit scripts.
• tx_to - The transaction containing the input to verify (the spending transaction)
• input_index - The zero-based index of the input within tx_to to verify
• flags - Verification flags specifying which consensus rules to enforce. If None, defaults to VERIFY_ALL. Combine multiple flags using bitwise OR (|).
• spent_outputs - The outputs being spent by the transaction. For SegWit and Taproot, this should contain all outputs spent by all inputs in the transaction. For pre-SegWit, this can be empty or contain just the output being spent. The length must either be 0 or match the number of inputs in the transaction.

Returns

• Ok(()) - Verification succeeded; the input properly spends the output
• Err(KernelError::ScriptVerify(ScriptVerifyError::TxInputIndex)) - Input index out of bounds
• Err(KernelError::ScriptVerify(ScriptVerifyError::SpentOutputsMismatch)) - The spent_outputs length is non-zero but doesn’t match the number of inputs
• Err(KernelError::ScriptVerify(ScriptVerifyError::InvalidFlags)) - Invalid verification flags
• Err(KernelError::ScriptVerify(ScriptVerifyError::InvalidFlagsCombination)) - Incompatible combination of flags
• Err(KernelError::ScriptVerify(ScriptVerifyError::SpentOutputsRequired)) - Spent outputs are required for this script type but were not provided
• Err(KernelError::ScriptVerify(ScriptVerifyError::Invalid)) - Script verification failed; the input does not properly satisfy the output’s spending conditions

Examples

Verifying a P2PKH transaction

let prev_output = prev_tx.output(0).unwrap();

let result = verify(
    &prev_output.script_pubkey(),
    None,
    &spending_tx,
    0,
    Some(VERIFY_ALL),
    &[] as &[TxOut],
);

Using custom flags

// Only verify P2SH and DERSIG rules
let custom_flags = VERIFY_P2SH | VERIFY_DERSIG;

let result = verify(
    &prev_output.script_pubkey(),
    None,
    &spending_tx,
    0,
    Some(custom_flags),
    &[] as &[TxOut],
);

Panics

This function does not panic under normal circumstances. All error conditions are returned as Result::Err.