Enum Error 

#[non_exhaustive]
pub enum Error {
    WrongLength {
        family: HeaderFamily,
        expected: usize,
        actual: usize,
    },
    VersionBit31Set,
    VersionBit31Clear,
    ReservedFlags(u8),
    InvalidHex,
    CompactNegative(u32),
    CompactOverflow(u32),
    BitsNotPowLimit {
        bits: u32,
        expected: u32,
    },
    TargetNotMet,
}

Why a header could not be decoded or does not satisfy a rule.

Each variant names the upstream rule it stands in for, so a rejection can be traced to the reference: the codec’s length check (codec/codec.js decode, “trailing bytes after BlockHeader”), the header-family selection on version bit 31 (siding/lib/parents.mjs, SPEC 3.2), Bitcoin Core’s arith_uint256::SetCompact overflow and negative cases, and siding’s pow rule (SPEC 4 step 1).

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

WrongLength

The byte slice is not the family’s wire size (80 or 164).

Fields

family: HeaderFamily

The family the bytes were decoded as.

expected: usize

That family’s wire size.

actual: usize

The length actually supplied.

VersionBit31Set

A stock header’s version has bit 31 set. Beside a stock parent the producer keeps it clear (siding/lib/block.mjs buildBlock, test/stock-header-test.mjs “version keeps bit 31 clear”); on a BLAKE2b-family chain the same bit would select the v2 layout, so a stock header carrying it is not a header of either family.

VersionBit31Clear

A v2 header’s version has bit 31 clear: the bytes are not a v2 header (isHeaderV2 in codec/pow/knots-header-v2.js).

ReservedFlags(u8)

A v2 header’s flags has a reserved bit (6 or 7) set (knots:rule-header-flags-reserved, error code bad-flags-highbits).

InvalidHex

A hex string was not 64 hex characters.

CompactNegative(u32)

Compact bits with the sign bit set and a non-zero mantissa (Core’s fNegative).

CompactOverflow(u32)

Compact bits whose mantissa would not fit in 256 bits (Core’s fOverflow).

BitsNotPowLimit

The header’s bits is not the compact encoding of the chain’s powLimit. Siding sets every block’s bits to that value (siding/lib/chain.mjs: compactFromTarget(powLimit)) and the kernel’s difficulty rule holds it there (powNoRetargeting).

Fields

bits: u32

The header’s bits.

expected: u32

powLimit in compact form.

TargetNotMet

The block hash, read as a 256-bit number, exceeds the target bits encodes (btc:rule-header-pow; SPEC 4 step 1).

Trait Implementations

impl Clone for Error

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Error

impl Debug for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Error

impl Error for Error

Available on crate feature std only.

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for Error

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Error