MultiversX Sharp Edges

This skill alerts you to non-obvious behaviors, "gotchas," and platform-specific quirks that often lead to bugs.

1. Async Callbacks & Reverts

• The Edge: When an Async Call fails, the #[callback] is executed.
• The Sharp Logic:
  • If you don't implement a callback, the funds return to the contract, but state changes in the original transaction are NOT reverted automatically.
  • Mitigation: You must manually revert state in the callback if the sub-call failed (or use the synchronous back_transfers carefully).

2. Gas Limits & Out of Gas (OOG)

• The Edge: OOG raises a specific error but can leave the system in a partial state if not handled.
• The Sharp Logic:
  • Cross-shard OOG: If the destination shard runs OOG, the transaction fails, but the sender shard has already processed the transfer. The callback is triggered with an error.