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Error

Reference for mo:core/Error in the core library.

Error wraps async rejection values and classification helpers for recovery paths. Use it with the required try/catch style around awaits so failure behavior is explicit in both code and specs.

Import​

mo:core/Error

Status​

  • Runtime module

Public API​

Types​

  • Error, ErrorCode

Functions​

reject(msg : Text) : Error​

Reads or constructs the error value used by async rejection handling.

Contract

ensures message(result) == msg;

Use when: code or specifications need this operation with the documented contract.

code(error : Error) : ErrorCode​

Reads or constructs the error value used by async rejection handling.

Use when: code or specifications need this operation with the documented contract.

message(error : Error) : Text​

Reads or constructs the error value used by async rejection handling.

Use when: code or specifications need this operation with the documented contract.

isCleanReject(error : Error) : Bool​

Checks the predicate described by the return contract.

Contract

ensures result == (switch (code error) {
case (#system_fatal or #system_transient or #destination_invalid or #call_error _) true;
case _ false
});

Use when: a branch condition or contract needs this predicate as a named fact.

isRetryPossible(error : Error) : Bool​

Checks the predicate described by the return contract.

Contract

ensures result == (switch (code error) {
case (#system_transient or #system_unknown) true;
case _ false
});

Use when: a branch condition or contract needs this predicate as a named fact.

Summary​

  • Runtime module under mo:core/Error.
  • Exposes 5 public functions.