Solving the UNPREDICTABLE_GAS_LIMIT Issue in Uniswap V3 Multihop Swaps скачать в хорошем качестве

Solving the UNPREDICTABLE_GAS_LIMIT Issue in Uniswap V3 Multihop Swaps

Learn how to effectively solve the `UNPREDICTABLE_GAS_LIMIT` error in Uniswap V3 when performing multihop swaps using the SwapRouter. --- This video is based on the question https://stackoverflow.com/q/71112147/ asked by the user 'mps' ( https://stackoverflow.com/u/18202431/ ) and on the answer https://stackoverflow.com/a/71156441/ provided by the user 'Naum PS' ( https://stackoverflow.com/u/6243016/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Can't use Uniswap V3 SwapRouter for multihop swaps, SwapRouter.exactInput(params) throws 'UNPREDICTABLE_GAS_LIMIT' Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- Troubleshooting the UNPREDICTABLE_GAS_LIMIT Error in Uniswap V3 Multihop Swaps When working with the exciting world of decentralized finance (DeFi), encountering obstacles can often feel like part of the journey. One such challenge developers face is the UNPREDICTABLE_GAS_LIMIT error while executing multihop swaps using Uniswap V3's SwapRouter. In this guide, we will delve into this issue and provide a clear solution to ensure your token swaps are seamless and efficient. Understanding the Issue What is the UNPREDICTABLE_GAS_LIMIT Error? This error typically arises when the Ethereum network (or any other blockchain, like Polygon) cannot accurately estimate the gas required for executing a transaction. In your specific case, it happens while trying to use the exactInput method of the SwapRouter for multihop swaps. The Context of the Problem While direct swaps work perfectly, attempting multihop swaps results in an error. It seems you have encountered an impediment regarding the encoded transaction parameters for your multihop swaps involving different token paths and fees. A Step-by-Step Solution 1. Rethinking the Path Encoding The key to resolving your issue lies in accurately encoding the parameters, specifically the fee values in your path. Here’s a simple breakdown of how to adjust your encodePath function to rectify the problem: Original Code Snippet: [[See Video to Reveal this Text or Code Snippet]] Modify the Fee Size: Change the FEE_SIZE from 3 to 6 to align with the correct encoding size for fees in the Uniswap V3 ecosystem. 2. The Revised Encoding Function Here is how your updated encodePath function should look after integrating the necessary changes: [[See Video to Reveal this Text or Code Snippet]] 3. Adjusting Your Swap Function Once you've revised the encoding function, ensure that your swapping logic calls it correctly. Here's an example for clarity: [[See Video to Reveal this Text or Code Snippet]] Conclusion In summary, the UNPREDICTABLE_GAS_LIMIT error when performing multihop swaps in Uniswap V3 can be effectively resolved by revisiting how you encode the path and associated fees. Ensuring the fee size is specified as 6 will align with the encoding expectations of the SwapRouter, paving the way for successful token swaps. Final Tips Regularly check the Uniswap documentation for updates or changes in the API. Validate each part of your coding logic with error handling to capture issues promptly. Engage with the developer community if you face hurdles; platforms like GitHub or Stack Overflow can be invaluable. Now take this knowledge and sharpen your skills in executing multihop swaps! Happy swapping!