amount (BigNumber) gets changed when using walletConnect

[ghost]

Hi community,

I got a very strange behaviour and I absolutly couldnt find a reason for.
I am writing a little dapp using
"vue": "^3.2.45"
"ethers": "^5.4.7"
"@web3-onboard/vue": "^2.7.10",
"@web3-onboard/walletconnect": "^2.4.5"

The app was done, everything works nice using Browser on Windows with MM, TW or WC with TW.
Tested on my OnePlus 6T. Everything fine.
Wanted to show this to a frind of mine on his Oneplus Nord100. And this happens.

I inserted some debug output to show the variables commited.
The strangest thing, the amount got crippled random. So it is not everytime the same amount getting missed. Sometimes it a very little more, sometime less.

    async approve(context,payload) {
        context.commit("setlasttxHash",'')
        const amount = ethers.utils.parseUnits(payload.toString(),'ether')
        context.commit("setLastError",amount.toString())
        if(context.getters.getNsfwAllowance.lte(amount)) {
            context.commit("setWaitForTransaction",true)
            console.log(amount.toString())
            context.getters.getNsfwContract.approve( context.getters.getNsfwSlotContractAddress, amount).then(
                (receipt) => {
                    context.commit("setlasttxHash",receipt.hash)
                    context.getters.getProvider.waitForTransaction(receipt.hash, 1, 60000)
                        .catch(err => {
                            context.commit("setLastError",err.msg)
                            context.commit("setWaitForTransaction",false)
                        } )
                        .finally( async ()  => {
                            context.commit("setWaitForTransaction",false)
                            await context.dispatch('refresh', context)
                        })
                }
            ).catch((err) => {
                context.commit("setWaitForTransaction",false)
                context.commit("setLastError",err.msg)
            } )
        }
    }

Here is the relevant code fragment. I tested some more devices, and it seems to be device specific.
Oneplus 6T - OK
iPhone XS - OK
Samsung A50 - OK
Oneplus Nord - Failed
uleFone Note P9 - Failed

I have absolutely no idea where this comes from and am grateful for any tip.

[ricmoo]

That looks like you aren’t using exact values. My guess is maybe typeof(payload) is number. When using Ethereum you should make sure you never use a JavaScript number (which is an IEEE 754 64-bit floating point).

The value should only ever be a string or BigInt (or in v5 a BigNumber); never let it get converted to a number. The parseEther utility will convert from a decimal string to a BigInt for you, retaining all precision and all maths using proper non-number maths will retain precision.

When using large values, you will expect about 50% of the time a number to be slightly too small and 50% of the time slightly too large. The only values that will be save are values that are safe in 64-bit floating points, which are quite rare.

Does that make sense?

[ricmoo]

Also, are you sure it is because of the device, and not because of the balance, etc. of the user? What if you use the same account on a Oneplus vs an iPhone?

[ghost]

Same amount on OnePlus 6T or iPhone works as described.

[ghost]

I added all those toString() (s) after I noticed the issue.
it's not the first time i've built dapps.
but the first time I come across such strange errors.
what has changed compared to the other projects is actually only walletconnect from V1 to V2 and vue from 2 to 3 (vite instead of vue-cli-service).

[ricmoo]

It is quite surprising to me that it would be platform dependant. I’m not really sure what it could be…

[ghost]

Same here .... i`ve hanging on this for days now.
Maybe the answer is to simple to see

[ghost]

Found the solution... its from the inside of vuex (currently using 4.1.0)
Tested some other dApps using the same setup, found the same strange behavior.
Recode my dapp with pinia 2.1.6, everything works as expected

Thanks for all the replies