on_notify does not get triggered

Question

I am using a very simple example:

mycontract.hpp:

[[eosio::on_notify("eosio.token::transfer")]] 
void depos(name from, name to, asset quantity, string memo);

mycontract.cpp:

[[eosio::on_notify("eosio.token::transfer")]] 
void depos(name from, name to, asset quantity, string memo) {
  check(false, "notification handler triggered successfully");
}

By calling eosio.token::transfer, the transaction happens successfully, but my function depos does not get called.

Answer 1

It seems that the contract containing the on_notify attribute should be either the sender or reciever of the transfer. This is not clearly mentioned in the manual

Answer 2

Notification is delivered by require_recipient. eosio.token::transfer calls require_recipient for from (sender of token) and to (recipient of token) account. As @towi_parallelism mentioned, only sender and recipient can get notification.

https://github.com/EOSIO/eosio.contracts/blob/d7bc0a5c/contracts/eosio.token/src/eosio.token.cpp#L89-L90

Answer 3

If you are using EOSIO_DISPATCH with ACTION keyword, then replace ACTION keyword with [[eosio::action]] void from your .hpp file and remove EOSIO_DISPATCH from your .cpp file of smart contract.

As EOSIO_DISPATCH blocks eosio::on_notify.

Also check: [[eosio::on_notify("VALID_EOSIO_ACCOUNT_NAME::VALID_EOSIO_ACTION_NAME")]] Ref: https://developers.eos.io/manuals/eosio.cdt/v1.6/guides/generator-attributes

Please closely check eosio.token contract you will get how use. https://github.com/EOSIO/eosio.contracts/tree/master/contracts/eosio.token