Enum ErrorDomain 

#[repr(i32)]
pub enum ErrorDomain {
    None = 0,
    Parser = 1,
    Tree = 2,
    Namespace = 3,
    Dtd = 4,
    Html = 5,
    Io = 8,
    XPath = 12,
    Xslt = 22,
    SchemasValidate = 17,
    RelaxNGValidate = 19,
    SchematronValidate = 28,
    Validation = 23,
    Encoding = 27,
}

Which subsystem raised the error.

Mirrors xmlErrorDomain from libxml2 (include/libxml/xmlerror.h) so that errors can be categorised without inspecting the message string, AND so that domain as i32 produces the exact numeric value a C caller sees through xmlError::domain after going through the [crates/compat] FFI shim. See thoughts/c_abi_implementation_plan.md § “Unified Rust error type, free conversion to libxml2 layout.”

Variant discriminants are pinned — do not renumber — they are part of the C ABI surface.

Variants

None = 0

No domain — used by libxml2 as the default value for fields it hasn’t initialised. We rarely emit this from Rust; included for round-trip.

Parser = 1

XML parser (well-formedness violations, unexpected tokens, etc.).

Tree = 2

Document tree manipulation.

Namespace = 3

Namespace resolution (undeclared prefix, duplicate declarations, etc.).

Dtd = 4

DTD processing and entity expansion.

Html = 5

HTML parsing errors (malformed tag soup, recovered errors from the HTML5 tree-construction algorithm).

Io = 8

I/O errors (file not found, read failure, etc.).

XPath = 12

XPath expression parsing or evaluation.

Xslt = 22

XSLT processing — stylesheet compile, transform errors.

SchemasValidate = 17

W3C XML Schema (XSD) validation. lxml’s error.domain_name → "SCHEMASV".

RelaxNGValidate = 19

RELAX NG validation. lxml’s error.domain_name → "RELAXNGV".

SchematronValidate = 28

Schematron validation. lxml’s error.domain_name → "SCHEMATRONV".

Validation = 23

Schema or DTD validation.

Encoding = 27

Character encoding errors (invalid UTF-8, unsupported encoding). libxml2 calls this domain “I18N” but it’s the encoding/charset error bucket.

Trait Implementations

impl Clone for ErrorDomain

fn clone(&self) -> ErrorDomain

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ErrorDomain

impl Debug for ErrorDomain

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

Formats the value using the given formatter.

impl Eq for ErrorDomain

impl PartialEq for ErrorDomain

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for ErrorDomain