Document msgpack.cfg.encode_error_as_ext

[Totktonada]

Product: Tarantool
Since:
Root document: https://www.tarantool.io/en/doc/latest/reference/reference_lua/msgpack/#msgpack-cfg
SME: @ locker
Peer reviewer: @

Details

The new option determines how error objects (see box.error.new) are
encoded in the msgpack format:

• If it's set, errors are encoded as the MP_ERROR msgpack extension.
  This is the default behavior.
• If it's unset, the encoded format depends on other msgpack
  configuration options (encode_load_metatables, encode_use_tostring,
  encode_invalid_as_nil). With the otherwise default configuration,
  they are encoded as strings (see error.message).

Functions affected by the default configuration (msgpack.cfg):

• msgpack and msgpackffi modules
• Storing errors in tuples and spaces (box.tuple.new)
• Returning errors from IPROTO CALL/EVAL

Requested by @locker in tarantool/tarantool@fa1652d