TS TSender UI (Read Contract Wagmi) Can't read allowance

[Leosmart855]

I doubt if this mock token address 0xe7f1725E7734CE288F8367e1Bb143E90bb3F0512 is still an erc20 contract, it has zero token when imported and can't read the allowance function. How do I get pass this error please..

[EngrPips]

Did you follow the instructions on this page https://github.com/Cyfrin/ts-tsender-ui-cu/blob/main/CONTRIBUTING.md to spin up your local Anvil chain?

[Leosmart855]

Sure I did, using tsender-deployed.json node via anvil --load-state tsender-deployed.json. I followed instruction through and through. On importing the token on the anvil local chain, it showed 0 MT balance unlike 100 MT in Patrick's tut

[EngrPips]

It may appear to change on the interface, but confirm in MetaMask itself that the current active network is Anvil. MetaMask sometimes defaults to the previously active network when you switch to a new network.

[Leosmart855]

I have done all of that. I believe the issue is from the MT contract. I even set up Anvil chain on another MetaMask wallet and imported the MT address and it is the same issue..

[EngrPips]

So I loaded the state and imported the wallet on my metamask and the balance showed up for me

[EngrPips]

So I also spun up the front-end and then transfer token, which worked fine for me. You can see images below

[EngrPips]

You can share your address with me so that I can send some token to you and we can see if you receive it. It seems like a problem on your end, not the code, not the contract.

[Leosmart855]

Hello EngrPips! First of all I really want to appreciate you immensely for your contribution so far, you are a gem bud!
So apparently I discovered that contract address does not work because when import, the MT token decimal defaults to 0 instead of 18 and MetaMask won't allow me edit it hence the zero balance I am getting indicating non existent contract. It never works and never will except the decimal changes to 18 like others, even at that, I can't send you address, remember it's the same default address for everyone where the token lives in so each user needs to spin up a deployed state on anvil for the import to work.

Well the good news is even though that did not work, I have been able to solve the major problem through the help of DeepSeek and errors are gone.

First, I made a mistake on my part by spinning up Anvil instead of pnpm run anvil, I forgot I saved load state in package.json script, hence missing the major error I should have got after loading state.

The second and major issue is that the state dump file (tsender-deployed.json) was created with an older version of Anvil that included detailed transaction tracing data (traces, decoded, ordering fields). While I am using a more recent Anvil version which uses a simpler, cleaner format without these fields, causing a version incompatibility.

I will outline the issue and solution directly from DeepSeek for the sake of others that may encounter this same issue in future

<Anvil State Dump Compatibility Issue - Solution Guide>

The Problem
When running pnpm run anvil with a state dump file, you get this error:
error: invalid value 'tsender-deployed.json' for '--load-state ': failed to parse json file: missing field index at line 371 column 15

Root Cause
The state dump file (tsender-deployed.json) was created with an older version of Anvil that included detailed transaction tracing data (traces, decoded, ordering fields). Your current Anvil version uses a simpler, cleaner format without these fields, causing a version incompatibility.

The Solution
Convert the old state dump format to the new, clean format that current Anvil versions expect.

Step 1: Create a conversion script
Create a file called convert-dump.js in your project root and paste the code:

const fs = require('fs');

// Load your old state dump
const oldData = JSON.parse(fs.readFileSync('tsender-deployed.json', 'utf8'));

// Create a clean state dump in current Anvil format
const newData = {
    block: {
        number: "0x0",
        beneficiary: "0x0000000000000000000000000000000000000000",
        timestamp: "0x1",
        gas_limit: 30000000,
        basefee: 1000000000,
        difficulty: "0x0",
        prevrandao: "0x0000000000000000000000000000000000000000000000000000000000000000",
        blob_excess_gas_and_price: {
            excess_blob_gas: 0,
            blob_gasprice: 1
        }
    },
    accounts: oldData.accounts,
    best_block_number: 0,
    blocks: [],
    transactions: [],
    historical_states: null
};

// Save in minified format
fs.writeFileSync('tsender-deployed-clean.json', JSON.stringify(newData));

console.log(' Converted to clean Anvil format');
console.log('File saved as: tsender-deployed-clean.json');
console.log('\nNow run: anvil --load-state tsender-deployed-clean.json');

Step 2: Run the conversion script
node convert-dump.js

Step 3: Update your package.json
Change the anvil script to use the new clean file:

"scripts": {
  "anvil": "anvil --load-state tsender-deployed-clean.json"
}

Step 4: Run Anvil
pnpm run anvil

Why This Works

1. Removes incompatible data: Strips out traces, decoded, ordering, and index fields that newer Anvil versions don't recognize

2. Preserves your contracts: Keeps all deployed contracts from the accounts object

3. Matches current format: Creates a state dump in the exact format your current Anvil version expects

Alternative Solution (If you have the contract source code)
If you have the original contract code, you can simply redeploy: But heck we don't have the original contract code.

Credits
This solution preserves your deployed contracts while converting to a format compatible with modern Anvil versions (Foundry).

With this I was able to get pass the error and arrive at same answer with our tutor. I hope this helps.

[EngrPips]

Welldone Man, Great Job!