"out of gas" bug

[kelonye]

Describe the bug

We're all of a sudden getting an "out of gas" error on some read calls (inflation_rate and working_supply) to this curve gauge contract. Please advice.

Reproduction steps

Please load up this example code, on mainnet.

Environment:

Note that this issue doesn't occur with Web3.js as evident in this demo.

[dbeal-eth]

this issue is most likely related to the Berlin upgrade. In the provided example code from @vbstreetz , if you add {gasLimit:100000} override to the inflation rate contract call, it works.

[ricmoo]

Read-only methods still have a gas limit, to prevent abuse. They do not cost ether, so services providing access to calls must protect their infrastructure another way.

Otherwise, you could imagine a contract with a method with while(1); in it, which when called with eth_call would chew up resources and hang the node forever.

Each backend chooses their own maximum gas limit for calls, I think some use twice the block gas limit, but it is up to each backend to choose this.

Each backend seems to have chosen its own set of rules too, regarding Berlin, in how it handles estimating gas and calls by default.

I can look into this and try adding logic to the BaseProvider to mitigate this, but in general it is best to include an explicit gasLimit, which in my own code I usually bake into the ABI. Both human-readable and JSON ABI support this, and if you use Vyper it is computed for you and included in the ABI.

[ricmoo]

Looking at your code, out of curiosity, what happens if you use the default provider instead of the window.ethereum wrapped in a Web3Provider? Also, are you certain your MetaMask (or such) is set to the correct network?

[dbeal-eth]

@ricmoo the example code link provided above can be edited, but I went ahead and used new ethers.providers.getDefaultProvider(); and the code worked.

[ricmoo]

If the code works with the default provider, my guess is whatever the source of your window.ethereum is is the source of the problem.

Is it MetaMask? Is it the latest version? It’s estimateGas method may be out of date; my guess is that it hasn’t updated its calculation for intrinsic gas cost. See if there is an update for it though. Berlin just came out, and there are certainly lots of parts of the community that are not completely ready yet… :s

[kelonye]

@ricmoo the example code link provided above can be edited, but I went ahead and used new ethers.providers.getDefaultProvider(); and the code worked.

Gotcha. Could it be the JsonRpcProvider, which I believe InfuraProvider is based on? See https://codesandbox.io/s/ethers-issue-0td32?file=/src/index.js.