ETH Fees Too Low? Pallet-Revive & 18 Decimals

Hey guys,

I'm diving deep into an issue I encountered while integrating the pallet-revive into my live chain, and I wanted to share the problem, my findings, and hopefully get some insights from you all. My chain currently operates with 18 decimals, and after updating the NativeToEthRatio to 1 (it was previously 1,000,000 when the chain used 12 decimals), I've been running into transaction failures. The logs indicate that the calculated ETH fee seems to be lower than what's actually required, and this is where things get interesting. So, let's break this down, analyze the logs, and figure out if pallet-revive is fully compatible with chains having 18 decimals or if there's a deeper issue at play.

The Problem: ETH Fee Calculation Discrepancy

The core issue revolves around the difference between the calculated ETH fee and the actual fee required for a transaction. When a transaction is attempted, the logs reveal a discrepancy that leads to the transaction's failure. The system calculates an ETH fee, but this calculated fee is lower than the actual fee the transaction demands. This is a critical problem because it directly impacts the usability of the chain and the pallet-revive functionality. Users are unable to execute transactions because the fee mechanism isn't accurately reflecting the network's demands. This not only frustrates users but also hinders the adoption and smooth operation of the chain. Imagine trying to send a transaction and continuously having it fail due to a fee miscalculation – it's a roadblock that needs immediate attention. So, understanding why this discrepancy occurs is crucial for maintaining a healthy and functional blockchain environment.

Decoding the Transaction Details: A Closer Look

To really understand what's going on, let's dissect the transaction details. The logs I've included provide a wealth of information, and each piece of data contributes to the bigger picture. We're talking about the Nonce, the Chain ID, the recipient address (To), the Value being transferred, the Gas limit, and the Gas Price. These are the fundamental components of any Ethereum-like transaction, and they all play a role in determining the transaction fee. When we look at the convert_evm_to_native function, we see it's responsible for converting values between the EVM (Ethereum Virtual Machine) and the native chain's representation. This is super important because we're dealing with different decimal precisions, and any miscalculation here can throw off the entire fee calculation. The NativeToEthRatio is particularly crucial – it dictates how values are translated between the native chain's units and ETH. Getting this ratio right is essential for accurate fee conversions. So, by meticulously examining these details, we can start to pinpoint where the fee calculation might be going awry.

Analyzing the Logs

Let's dive into those logs and see what they tell us! The logs provide a step-by-step breakdown of the fee calculation process, and they're our best tool for diagnosing the issue. We see the transaction details clearly laid out: Nonce, Chain ID, recipient address, value, gas limit, and gas price. Then, the logs show the convert_evm_to_native function in action, converting both the transaction value and the raw ETH fee. This conversion is where the NativeToEthRatio comes into play, and we can see its value is set to 1. This seems correct, given the chain's 18 decimals and the previous adjustment from a 12-decimal setup. However, the critical part is the comparison at the end: actual_fee: 127000000933060127 versus eth_fee: 125000001960000000. This discrepancy – the ETH fee being lower than the actual fee – is the heart of the problem. The logs clearly indicate that the calculated ETH fee is insufficient, leading to transaction failures. By carefully tracing these values and understanding the conversion process, we can start to formulate hypotheses about why this underestimation is happening. Maybe there's a rounding issue, or perhaps the gas estimation within pallet-revive isn't fully accounting for the cost of operations on a chain with 18 decimals. The logs are our roadmap to finding the root cause.

The Role of NativeToEthRatio and Decimal Precision

Now, let's talk precision. The NativeToEthRatio is the bridge between our native chain's currency and Ether. It's how we translate values back and forth, and it's super important for getting the fees right. When we shifted from 12 decimals to 18 decimals, we updated this ratio, but it seems like there might still be some lingering issues. With 18 decimals, we're dealing with much smaller fractions, and even tiny discrepancies in calculations can add up. The convert_evm_to_native function is designed to handle these conversions, but we need to make sure it's doing so perfectly. We're seeing that the calculated ETH fee is lower than the actual fee, so it's possible that the conversion process is losing some precision somewhere along the line. Maybe there's a rounding error, or maybe the gas estimation within pallet-revive isn't fully accounting for the intricacies of an 18-decimal chain. It's also worth considering how the EVM itself handles these higher precisions and whether there might be any interactions causing the miscalculation. Understanding these nuances is key to fine-tuning the fee calculation mechanism.

Is Pallet-Revive Fully Compatible with 18 Decimals?

This is the million-dollar question! Is pallet-revive playing nice with our 18-decimal chain? Based on the logs, there's a strong suspicion that something's not quite right. The fee discrepancy suggests that the pallet might not be fully accounting for the higher precision when calculating gas costs. It's possible that some internal calculations or conversions are optimized for lower decimal counts, and that's causing the underestimation. To really nail this down, we need to dig into the pallet's code and see how it handles gas calculations and value conversions. We should be looking for any potential rounding errors, integer overflows, or assumptions about decimal precision that might be causing the issue. It's also worth checking if there are any known issues or discussions within the Substrate and pallet-revive communities about compatibility with chains using 18 decimals. If others have encountered similar problems, their insights could be invaluable. Ultimately, we need to be confident that pallet-revive can accurately handle the intricacies of our chain's decimal setup, or we'll continue to see these transaction failures.

Potential Causes and Troubleshooting Steps

Alright, let's put on our detective hats and brainstorm some potential causes for this fee discrepancy. First off, rounding errors are a classic suspect when dealing with decimal conversions. Even tiny rounding mistakes can add up, especially when you're multiplying by gas limits and prices. We need to meticulously review the convert_evm_to_native function and any other relevant code to make sure rounding is being handled correctly. Integer overflows are another potential culprit. If we're dealing with very large numbers due to the 18 decimals, it's possible that some intermediate calculations are exceeding the maximum value of an integer type, leading to unexpected results. Gas estimation within pallet-revive could also be the issue. The pallet needs to accurately predict the gas cost of operations on our chain, and if it's underestimating, that could explain the fee discrepancy. We should examine how pallet-revive calculates gas and whether it's taking into account the specific characteristics of our 18-decimal setup. Finally, it's worth considering interactions with other pallets or runtime logic. Maybe there's a subtle conflict or unexpected behavior that's influencing the fee calculation. To troubleshoot, we can start by adding more logging to the relevant functions, giving us a more granular view of the calculations. We can also try simplifying the transaction to isolate the issue and rule out any external factors. Debugging this might be a bit of a puzzle, but with careful analysis, we can crack it!

Seeking Community Insights and Solutions

This is where we tap into the collective brainpower of the Substrate community! I'm posting this because I believe that someone out there has either faced a similar issue or has the expertise to shed some light on this. Have you guys encountered fee calculation problems with pallet-revive on chains with high decimal precision? Any insights or suggestions on where to look for the root cause would be incredibly helpful. Maybe you've got a knack for debugging Substrate runtime code or have a deep understanding of how gas estimation works. Sharing your knowledge could save me (and others) a lot of time and frustration. The Substrate community is known for its collaborative spirit, and I'm confident that together, we can unravel this mystery. So, if anything in this post resonates with you, please chime in! Your thoughts and experiences are highly valued.

I hope this detailed breakdown helps in understanding the issue and potentially finding a solution. Let's discuss this further and get those fees calculated correctly!