SBE > logging library flag

[anegg0]

@GreatSoshiant, please review the main issue. It seems there is a discrepancy in the basic_examples/events

[Cripto5588]

This task is a direct follow-up to the discrepancy noted in #2501.

Technical Context: > The current documentation in vm-differences.mdx (and others) still points to an obsolete way of handling events. As requested in #2501, we need to standardize the use of:

#[event] macro for ABI generation.

evm::log for proper host integration.

alloy-primitives for type safety.

Without these, the 'basic examples' mentioned by Pete in #2501 remain broken for end-users."

[Cripto5588]

Comparison & Fix Details (Line 563)
Current Obsolete State (Hidden Failure):

Solidity
// In docs/stylus/concepts/vm-differences.mdx
function process(uint256[] calldata data) public {
uint256[] memory results = engine.complex_calculation(data);
// Store results, emit events, etc. <--- Generic comment, no Rust implementation
}
Proposed Correct Implementation (Ready for v0.5.0+):

Rust
use stylus_sdk::{prelude::*, evm, msg};
use alloy_primitives::{Address, U256};

#[event]
pub struct Transfer {
#[indexed]
pub from: Address,
#[indexed]
pub to: Address,
pub value: U256,
}

// Inside the contract implementation:
evm::log(Transfer {
from: msg::sender(),
to,
value
});
Why this is mandatory:

ABI Visibility: Without #[event], the event is omitted from the generated JSON ABI, breaking frontend integration.

Host Integration: evm::log ensures the correct Stylus host call, preventing execution reverts or silent drops during testnet deployment.

Developer Experience: Replaces a theoretical comment with a copy-pasteable, working example.