The blacklist!

[owodunni]

We need to be able to blacklist tokens. This can be done at two points.

1. When finding the tokens
2. When dpoing trades

When can use the Hardhat network to trade against a forked ethereum chain. On that chain we can detect any bad tokens and add them to the blacklist!

[owodunni]

Creat article regarding why tokens can be weird:
https://medium.com/hummingbot/the-myth-of-the-erc-20-token-standard-ab0d76cf8532

[owodunni]

Even though the #97 took away some of the main issues that required the implementation of the Blacklist it is still a valid feature.

Here is a log from executing a trade against a invlaid token:

2021-01-23 09:36:42,842 [MainThread  ] [INFO ]  Executing trade 
Trade(
    pools:[
Pool(
  Tokens: [Token(Name: NiceToken, Price: 0.364173587419268, Address: 0x53F64bE99Da00fec224EAf9f8ce2012149D2FC88), Token(Name: Wrapped Ether, Price: 1, Address: 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2)],
  Balances: [Balance(Token: NiceToken, Value: 30.019577880574428), Balance(Token: Wrapped Ether, Value: 9.12832906154464)],
  Weights: [Balance(Token: NiceToken, Value: 0.5), Balance(Token: Wrapped Ether, Value: 0.5)],
  Fee: 0.003
  Address: 0x6D5416567E09b99D7B4b7897129Edb19C2F1305A), 
Pool(
  Tokens: [Token(Name: NiceToken, Price: 0.364173587419268, Address: 0x53F64bE99Da00fec224EAf9f8ce2012149D2FC88), Token(Name: Tether USD, Price: 0.0008174873575946463, Address: 0xdAC17F958D2ee523a2206206994597C13D831ec7)],
  Balances: [Balance(Token: NiceToken, Value: 4.8879831779332665), Balance(Token: Tether USD, Value: 2260.513207)],
  Weights: [Balance(Token: NiceToken, Value: 0.5), Balance(Token: Tether USD, Value: 0.5)],
  Fee: 0.003
  Address: 0x2CC61dA33Bc68e541ED9e4BcE07AD3FD3d37ff60), 
Pool(
  Tokens: [Token(Name: RottenToken, Price: 2.601781834255753e-06, Address: 0xD04785C4d8195e4A54d9dEc3a9043872875ae9E2), Token(Name: Tether USD, Price: 0.0008174873575946463, Address: 0xdAC17F958D2ee523a2206206994597C13D831ec7)],
  Balances: [Balance(Token: RottenToken, Value: 690242.9748620626), Balance(Token: Tether USD, Value: 2207.706655)],
  Weights: [Balance(Token: RottenToken, Value: 0.5), Balance(Token: Tether USD, Value: 0.5)],
  Fee: 0.003
  Address: 0xE488C45ADEa8d83E25EbC548F711CeF799E5A24E), 
Pool(
  Tokens: [Token(Name: BloodyToken, Price: 5.125515127799606e-07, Address: 0x892F5A0B08BB7B1eeCCCC63EF3916fF201c93664), Token(Name: RottenToken, Price: 2.601781834255753e-06, Address: 0xD04785C4d8195e4A54d9dEc3a9043872875ae9E2)],
  Balances: [Balance(Token: BloodyToken, Value: 9476862.44238604), Balance(Token: RottenToken, Value: 1535591.0704434272)],
  Weights: [Balance(Token: BloodyToken, Value: 0.5), Balance(Token: RottenToken, Value: 0.5)],
  Fee: 0.003
  Address: 0x7d2C778A923648A7288e38554b9433BE8d51B57E), 
Pool(
  Tokens: [Token(Name: BloodyToken, Price: 5.125515127799606e-07, Address: 0x892F5A0B08BB7B1eeCCCC63EF3916fF201c93664), Token(Name: Wrapped Ether, Price: 1, Address: 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2)],
  Balances: [Balance(Token: BloodyToken, Value: 10628726.711341627), Balance(Token: Wrapped Ether, Value: 5.447769954822926)],
  Weights: [Balance(Token: BloodyToken, Value: 0.5), Balance(Token: Wrapped Ether, Value: 0.5)],
  Fee: 0.003
  Address: 0xc01E75AFbEdD5F9B9B8BCC619852D839B182cD38)],
    path:[Token(Name: Wrapped Ether, Price: 1, Address: 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2), Token(Name: NiceToken, Price: 0.364173587419268, Address: 0x53F64bE99Da00fec224EAf9f8ce2012149D2FC88), Token(Name: Tether USD, Price: 0.0008174873575946463, Address: 0xdAC17F958D2ee523a2206206994597C13D831ec7), Token(Name: RottenToken, Price: 2.601781834255753e-06, Address: 0xD04785C4d8195e4A54d9dEc3a9043872875ae9E2), Token(Name: BloodyToken, Price: 5.125515127799606e-07, Address: 0x892F5A0B08BB7B1eeCCCC63EF3916fF201c93664), Token(Name: Wrapped Ether, Price: 1, Address: 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2)],
    amount_in:0.106377372391389,
    profit:0.0231498027283421,
    balance:None,
    ratio:0.6648477650447155)
2021-01-23 09:36:42,940 [MainThread  ] [WARNI]  execution reverted: UniswapV2: K

Idealy this should add the failing token to the Blacklist.