Ethereum: Why Outputs’ Spendable and Solvable Are False
In the world of blockchain technology, especially in Ethereum, the concept of spendable and solvable outputs can be misleading. As a developer or researcher familiar with the Ethereum ecosystem, it’s essential to understand what these terms mean and why they might appear false.
What are expendable and solvable outputs?
In Ethereum, a transaction is considered “spendable” when its output is redeemable for Ether (ETH) at a rate of one ETH per unit. In other words, an output can be spent on something in exchange for a certain amount of ETH. This output’s ability to be expendable determines whether it has any value or utility.
On the other hand, an output is considered “solvable” when its weight (i.e., the number of gas units needed to call a function) is solvable by the Ethereum Virtual Machine (EVM). Solvability refers to whether the function’s gas limit can be fulfilled within the transaction’s execution time frame. When an output has both spendable and solvable properties, it means that:
- Spendable: The output cannot be spent directly for ETH without some additional process or action.
- Solvable: The output’s weight is within the EVM’s gas limit, allowing it to be executed.
Why are both expendable and solvable outputs false?
The reason inputs (i.e., the “spendable” part) might appear false is that they have been removed from the transaction. In Ethereum, when a transaction includes an input, it means that the output has already been spent or has no value. This is because transactions are designed to be one-way: once the transaction is executed, the inputs and outputs are no longer “spendable” in the traditional sense.
On the other hand, an output’s solvable property can still hold even if its input is removed from the transaction. For instance, if a function call has been optimized or cached by the EVM to reduce gas consumption, it can still be executed with the same weight (i.e., solvable). However, this does not mean the original output was “spendable.”
What does this mean for developers and users?
If you encounter an Ethereum transaction that appears to have a spendable but not solvable output, there are several possibilities:
- Function has been optimized: The function call might have been rewritten to reduce gas consumption, making it more efficient to execute.
- Gas limit was increased: The user or developer might have manually increased the EVM’s gas limit on an input or function call to account for optimization or caching.
- Transaction is incomplete: In some cases, a transaction can be partially executed without including all necessary inputs or outputs.
To verify whether a particular output is expendable and solvable in Ethereum:
- Check the transaction details: Look at the “txid” field to ensure the input has been removed from the transaction.
- Check the function name and parameters: Ensure that the function call has not been optimized for caching or other purposes.
- Use tools like
ethers.jsoreth-abito inspect the EVM’s gas usage and output weights.
In conclusion, Ethereum’s spendable and solvable outputs can appear false due to various reasons such as function optimizations or increased gas limits. Developers and users should be aware of these nuances when working with transactions in this ecosystem.