Error

An Error is a Lua table that identifies a failure with a stable code and a human-readable message. Native bindings raise these values, and scripts can create them with mux.error.new or mux.error.raise. Use an Error as the second result in the recoverable nil, err convention, or raise it when the current operation cannot continue.

Fields

string code

The dotted error code. It can be compared as a string, but checked symbols from mux.error.codes catch misspellings at lookup time.

string message

A readable description of the failure.

any detail

Optional structured context supplied by the producer. Native argument errors use a table containing argument.

any cause

Optional earlier error or other Lua value. mux.error.wrap stores the normalized wrapped value here.

string traceback

Optional traceback attached by mux.error.pcall when it catches a failure.

Methods

is

error:is(code)

string or code node code

A comparison string or a node from mux.error.codes or mux.error.namespace. Plain strings are used verbatim and are not syntax-validated.

Returns true when this error’s code is an exact match or begins with code at a dotted segment boundary.

root

error:root()

Returns this error’s deepest table-valued cause; it returns the error itself when there is no table-valued cause. Traversal is limited to 64 cause links.

Notes

tostring(error) renders code: message. Code matching is exact for a leaf, or matches a dotted prefix at a segment boundary: mux.state matches every mux.state.* error but not mux.statement.

Failed callbacks are always written to the Lua problem log. The lua.error_reporting setting controls player-visible notifications: off sends none, wizards sends details only to Wizards, and all sends details to everyone; otherwise notified players see A script error occurred.

See Also

• mux.error
• mux.error.codes
• Lua errors