Rollback/Reapply
Building on our pre-confirmation system, Arch implements a sophisticated rollback and reapply mechanism to maintain state consistency between Bitcoin's finality model and Arch's high-performance execution environment. This architecture uses the DAG Graph to track transaction dependencies, enabling deterministic handling of cross-chain inconsistencies.
Rollback Process
When Bitcoin-anchored transactions fail to confirm (due to mempool eviction, chain reorganizations, or transaction drops), Arch initiates a rollback:
- Graph Construction: Starting from the failed transaction, the system walks backward to gather dependencies and forward to identify affected children
- Validation: Confirms anchoring status of each transaction, excluding previously rolled-back nodes
- Recursive Execution: Traverses and marks all affected transactions, applying rollbacks in dependency-aware order
Importantly, this process operates with transaction-level granularity, allowing the system to roll back specific transaction chains without disrupting the entire network.
Reapply Process
When previously failed transactions eventually confirm on Bitcoin:
- Graph Rebuild: Starting with the reapply candidate, the system rebuilds dependencies and forward-traverses to include affected children
- Topological Execution: Ensures dependencies execute in the correct order
Developer Benefits
This mechanism automatically manages the complexities of Bitcoin's probabilistic finality while preserving Arch's high-performance capabilities. Developers gain:
- Clean application logic without Bitcoin-specific error handling
- Transaction consistency regardless of Bitcoin confirmation delays
- Graceful handling of chain reorganizations
- The security guarantees of Bitcoin with responsive performance
The rollback/reapply architecture allows developers to build confidently on Bitcoin without sacrificing reliability or user experience, even under volatile network conditions.