Incorrect USD price of tokens in menu

[pavel-lens]

Describe the bug
The USD price of tokens in Menu is incorrect. It shows huge amount of USD - around ±100x more as the real value. I'm not sure if it's only a problem of decimal point or the prices are totally wrong. It's obviously connected to where token prices are coming from.

To Reproduce
Steps to reproduce the behavior:

1. Open Metamask extension
2. Click on the hamburger menu in top left corner
3. Scroll down to tokens
4. Inspect prices

Expected behavior
A correct value in USD should be displayed.

Examples of tokens with invalid USD prices: Crypto20 C20, Gnosis GNO

Screenshots
https://pasteboard.co/HSUIZwg.png

Browser details (please complete the following information):

• OS: MacOS 10.14 Mojave
• Browser: Brave Version 0.58.16 Chromium: 71.0.3578.98 (Official Build) (64-bit)
• MetaMask Version 5.2.2

Additional context
n/a

[tmashuang]

Has it updated after a while to the correct price? We use an external API for token prices/rates, they we have no control over.

[pavel-lens]

I saw some change in price in few seconds. But the prices I provided screenshot of are after the change. These prices are apparently way off, so I think there is some calculation error on Metamask side. If not, then the API prices are off. If you point me to the right file I can have a look and create a PR with fix.

[tmashuang]

I started here, where the API call starts. token-rates.js.

I just Postman'd the request for the Gnosis contract(0x6810e776880c02933d47db1b9fc05908e5386b96).
Request: https://exchanges.balanc3.net/pie?pairs[]=0x6810e776880c02933d47db1b9fc05908e5386b96/usd&autoConversion=true. But will investigate the calculation as well.

[pavel-lens]

Okay, the retrieval logic in token-rates.js seems fine.

I looked at how prices are displayed at token-cell.js. It's a bit complicated, but it seems that the problem is that this calculation is being done:

tokenAmount * ethUsdPrice * tokenUsdPrice

In short, multiplication by ethUsdPrice is not necessary since the API already returns price of token in USD. This should be removed / changed
https://github.com/MetaMask/metamask-extension/blob/develop/ui/app/components/token-cell.js#L66

Metamask should only multiply token price stored in state.metamask.conversionRate[address] and token amount in the wallet.

[tmashuang]

Looking deeper we select the native currency selected here
https://github.com/MetaMask/metamask-extension/blob/develop/app/scripts/controllers/token-rates.js#L32

I believe we should still have ethUsdPrice in the calculation.

[tmashuang]

Upon buying GNO tokens, it seems the price for that seems fine with the current calculation.

[aminelarhrib2020]

hi ,
We have the same issue with CRD token price .
https://ethplorer.io/address/0xcaaa93712bdac37f736c323c93d4d5fdefcc31cc
metamask is displaying the wrong price . could you please help . there is 10X price difference , which is very confusing
many thanks !!