Enum DecodeError 

#[non_exhaustive]
pub enum DecodeError {
    BadMagic,
    VersionMismatch {
        supported: u8,
        received: u8,
    },
    UnknownMessageType(u8),
    UnknownDurability(u8),
    HeaderCrcMismatch {
        expected: u32,
        computed: u32,
    },
    PayloadCrcMismatch {
        expected: u32,
        computed: u32,
    },
    TruncatedFrame,
    PayloadTooLarge {
        len: usize,
        cap: usize,
    },
    ReservedFlagsSet {
        flags: u8,
    },
    TrailingBytes {
        extra: usize,
    },
}

All errors that can occur when decoding a weir wire frame.

Each variant identifies a specific frame-validation failure, and the daemon maps it to a distinct Nack reason byte: VersionMismatch is kept separate from BadMagic and HeaderCrcMismatch so the daemon can return its WIRE_VERSION in the Nack payload. The variants are NOT declared in strict decode order — the decoder validates magic → version → header CRC → message_type / durability → payload fields (so e.g. UnknownMessageType only arises on an already-CRC-valid header). Match on the variant, never on its position.

#[non_exhaustive]: the decode taxonomy is expected to grow (wire v1 already gained ReservedFlagsSet and TrailingBytes during the 1.0 hardening), so downstream matches must include a wildcard arm and adding a variant later is not a breaking change.

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.

BadMagic

First four bytes are not b"WEIR". Not a weir frame or stream is desynced.

VersionMismatch

Version byte does not equal WIRE_VERSION. Carries both sides for error messaging. Checked before header CRC so a version-mismatched frame from a newer client gets VersionMismatch, not a confusing HeaderCrcMismatch.

Fields

supported: u8

The WIRE_VERSION this build supports.

received: u8

The version byte carried by the rejected frame.

UnknownMessageType(u8)

Message type byte has no known variant.

UnknownDurability(u8)

Durability byte has no known variant.

HeaderCrcMismatch

Header CRC32 (bytes [12..16]) does not match CRC of bytes [0..12].

Fields

expected: u32

CRC carried in the header.

computed: u32

CRC computed over bytes [0..12].

PayloadCrcMismatch

Payload CRC32 (trailing 4 bytes) does not match CRC of the payload bytes.

Fields

expected: u32

CRC carried in the trailing 4 bytes.

computed: u32

CRC computed over the payload bytes.

TruncatedFrame

Buffer is shorter than the declared frame length.

PayloadTooLarge

payload_len exceeds the hard cap. Rejection happens before any heap allocation.

Fields

len: usize

The declared payload length.

cap: usize

The hard cap it exceeded.

ReservedFlagsSet

The reserved flags byte was nonzero. In wire v1 flags must be zero; a daemon rejects a frame that sets any flag bit rather than silently ignoring it (F52). Carries the offending byte.

Fields

flags: u8

The nonzero flags byte the frame carried.

TrailingBytes

The buffer was longer than the single frame it declared. Envelope::decode requires its input to be exactly one frame (HEADER_LEN + payload_len + 4 bytes): a longer buffer is rejected rather than decoding the first frame and silently discarding the remainder, so the caller — not the codec — owns framing and an over-long buffer surfaces as an error, not lost data (G18).

Fields

extra: usize

The number of bytes past the declared frame length.

Trait Implementations

impl Debug for DecodeError

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

Formats the value using the given formatter.

impl Display for DecodeError

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

Formats the value using the given formatter.

impl Eq for DecodeError

impl Error for DecodeError

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 From<DecodeError> for WeirError

fn from(e: DecodeError) -> Self

Converts to this type from the input type.

impl PartialEq for DecodeError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for DecodeError