Erc20flash mint #407

Ifechukwudaniel · 2024-11-14T04:27:09Z

Resolves #355

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Ifechukwudaniel · 2024-11-14T04:27:46Z

This is my initial draft

0xNeshi

Hi @Ifechukwudaniel!
Thanks for the contribution!

The PR overall looks good, let's polish it a bit

0xNeshi · 2024-11-14T07:54:53Z

contracts/src/flashloan/borrower.rs

+
+use stylus_sdk::stylus_proc::sol_interface;
+
+sol_interface! {


@bidzyyys @qalisander @ggonzalez94 on the one hand this should be defined inside contracts/src/token/erc20/extensions/flashmint.rs, similar to how IERC721Receiver is defined inside contracts/src/token/erc721/mod.rs

But on the other hand, Solidity version treats this trait (interface) as a standalone file within contracts/interfaces, similar to how we've done by placing Erc1155Receiver in the same folder as Erc1155.

What is the convention we want to use here?

EDIT: actually both examples I linked to (IERC721Receiver and Erc1155Receiver) technically use a similar convention, the difference being the latter's module is just placed in a separate file.

Making a whole file is not necessary and is not the way it has been done in the codebase. Instead, what I did was add it to the utility of ERC-20, as it is isolated to ERC-20

To follow the existing convention, place IERC3156FlashBorrower inside contracts/src/token/erc20/extensions/flashmint.rs (see the EDIT in my previous message).

contracts/src/flashloan/borrower.rs

contracts/src/token/erc20/extensions/flashmint.rs

0xNeshi · 2024-11-14T08:29:50Z

contracts/src/token/erc20/extensions/flashmint.rs

+    pub fn _flash_fee_receiver(&self) -> Address {
+        Address::ZERO
+    }
+}


Missing unit tests

0xNeshi · 2024-11-14T08:30:11Z

contracts/src/token/erc20/extensions/flashmint.rs

+    pub fn _flash_fee_receiver(&self) -> Address {
+        Address::ZERO
+    }
+}


Missing integration tests

0xNeshi · 2024-11-14T08:30:31Z

contracts/src/token/erc20/extensions/flashmint.rs

+    pub fn _flash_fee_receiver(&self) -> Address {
+        Address::ZERO
+    }
+}


Update CHANGELOG

0xNeshi · 2024-11-14T08:43:59Z

contracts/src/token/erc20/extensions/flashmint.rs

+    pub fn _flash_fee_receiver(&self) -> Address {
+        Address::ZERO
+    }
+}


Update antora docs docs/modules/ROOT/pages/erc20.adoc

Co-authored-by: Nenad <[email protected]>

chore: fixed tab

Create erc20-flashloan.adoc

chore: fixes

Ifechukwudaniel · 2024-11-18T03:21:35Z

@0xNeshi what do you think about the new implementation for the extension

0xNeshi · 2024-11-18T07:05:30Z

scripts/e2e-tests.sh

 cargo build --release --target wasm32-unknown-unknown -Z build-std=std,panic_abort -Z build-std-features=panic_immediate_abort

 export RPC_URL=http://localhost:8547

-cargo test --features std,e2e --test "*"
+cargo test --features std,e2e --test "erc20-flashloan"  -- --nocapture 


revert changes to this file

yeah will do that

0xNeshi · 2024-11-18T07:11:22Z

examples/erc20/src/lib.rs

@@ -6,7 +6,10 @@ use alloc::vec::Vec;
 use alloy_primitives::{Address, FixedBytes, U256};
 use openzeppelin_stylus::{
    token::erc20::{
-        extensions::{capped, Capped, Erc20Metadata, IErc20Burnable},
+        extensions::{
+            capped, flashmint::IERC3156FlashLender, Capped, Erc20Metadata,


What purpose does the trait import serve here?

0xNeshi · 2024-11-18T07:34:18Z

examples/erc20-flashmint/src/constructor.sol

+    uint256 private _totalSupply;
+    uint256 private _flash_fee_amount;
+    address private _flash_fee_receiver_address;
+    constructor(address flash_fee_receiver_address_, uint256 flash_fee_amount_) {


Format the contract to make it a bit more readable, you can use Remix to do that

0xNeshi · 2024-11-18T07:38:40Z

examples/erc20-flashmint/src/ERC3156FlashBorrowerMock.sol

+import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v5.1.0/contracts/interfaces/IERC3156FlashBorrower.sol";
+
+
+contract ERC3156FlashBorrowerMock is IERC3156FlashBorrower {


Format the contract

0xNeshi · 2024-11-18T07:47:05Z

examples/erc20-flashmint/src/ERC3156FlashBorrowerMock.sol

+
+            if (data.length > 0) {
+                // WARNING: This code is for testing purposes only! Do not use.
+                Address.functionCall(token, data);


I think you may be missing some imports (Address, IERC20), did you verify the tests pass?

0xNeshi · 2024-11-18T08:16:23Z

contracts/src/token/erc20/extensions/flashmint.rs

+    ) -> Result<bool, Self::Error>;
+}
+
+/// A Permit error.


Still wrong docs, please resolve a comment only after it's been fully addressed

0xNeshi · 2024-11-18T08:52:47Z

contracts/src/token/erc20/extensions/flashmint.rs

+
+}
+
+const RETURN_VALUE: B256 =


Actually, let's make the const clearer by default:

const RETURN_VALUE: [u8; 32] = keccak_const::Keccak256::new() .update("ERC3156FlashBorrower.onFlashLoan".as_bytes()) .finalize();

0xNeshi · 2024-11-18T10:01:12Z

contracts/src/token/erc20/extensions/flashmint.rs

@@ -0,0 +1,326 @@
+//! Optional Flashloan extension of the ERC-20 standard.


Copy/paste docs from the Solidity contract version, and update as appropriate for Stylus (follow the convention set in other contracts)

Check this out -> https://docs.openzeppelin.com/contracts/5.x/api/token/erc20#ERC20FlashMint

0xNeshi · 2024-11-18T10:13:00Z

contracts/src/token/erc20/extensions/flashmint.rs

+
+sol_storage! {
+    pub struct Erc20Flashmint  {
+       uint256 _flash_fee_amount;


Why do you need this contract state?

0xNeshi · 2024-11-18T10:15:08Z

contracts/src/token/erc20/extensions/flashmint.rs

+}
+
+sol_storage! {
+    pub struct Erc20Flashmint  {


I think a different (and arguably simpler) approach is warranted for implementing the flash mint contract.

The ERC20FlashMint contract extends ERC20 with 3 new functions, and by the spec, it does not introduce any new state nor override existing ERC20 functions (see Solidity version).
In other words, this means that this contract (extension) should inherit and include all ERC20 functionality, and just add these 3 new functions.

In short, it should be enough to simply implement the IERC3156FlashLender trait for Erc20 (similar to IErc20Burnable).

Implement the IERC3156FlashLender trait for Erc20.

Copy/paste the logic from the Solidity version linked above.

Create meaningful unit and integration tests (use Solidity version tests as inspiration).

Remove redundant code/comments that are spread throughout the PR.

Update comment docs to follow already set conventions, e.g. use SafeErc20 as inspiration (some may consider comments as overly detailed, but it is better to be clear when building potentially widely used OS code). You can generally copy/paste Solidity contract docs, and update where necessary.

Add missing ADOC content for the contract, e.g. see Erc20Permit docs.

Format Solidity code according to conventions set in other contracts.

Format Rust code and markdown according to GUIDELINES.md.

(optional) add benchmarks (see ./benches)

What do you think about this?

it does implement the internal functions _flash_fee and _flash_fee_receiver so they can be overridden and support extensibility, any suggestion of an approach I can use for that

The reason why i went with that current approach is because of those internal functions @0xNeshi

_flash_fee and _flash_fee_receiver are not part of the spec (see EIP-3156), so they are not required to exist.

Also, since inheritance is still limited in Stylus, overriding does not work as you might expect in other more object-oriented languages.

In short, _flash_fee and _flash_fee_receiver don't make as much sense in Stylus as they do in Solidity.

smaller chages

bidzyyys

Thanks for your contribution @Ifechukwudaniel!
I left some comments. Do you want to solve them by yourself or should we handle them?

bidzyyys · 2024-11-25T14:07:25Z

contracts/src/token/erc20/extensions/flashmint.rs

@@ -0,0 +1,326 @@
+//! Optional Flashloan extension of the ERC-20 standard.


Check this out -> https://docs.openzeppelin.com/contracts/5.x/api/token/erc20#ERC20FlashMint

contracts/src/token/erc20/utils/borrower.rs

examples/erc20-flashmint/src/lib.rs

bidzyyys · 2024-11-25T14:13:46Z

contracts/src/token/erc20/utils/borrower.rs

I believe there should be module erc20::extensions::flashmint with borrower.rs file.

examples/erc20-flashmint/src/lib.rs

bidzyyys · 2024-11-25T14:19:29Z

examples/erc20-flashmint/src/lib.rs

+    }
+}
+
+impl Erc20FlashMintExample {


Why do we need additional logic in the example? Is it possible to include this logic in FlashMint Extension code?

for cases where we users would like to implement custom borrower and receiver functions

bidzyyys · 2024-11-25T14:20:09Z

examples/erc20-flashmint/tests/erc20-flashloan.rs

+    let Erc20Flashmint::totalSupplyReturn { totalSupply } =
+        contract.totalSupply().call().await?;
+
+    // let Erc20Flashmint::maxFlashLoanReturn { maxLoan: testMaxLoan } =


Unused logic, please make it work.

bidzyyys · 2024-11-25T14:21:00Z

examples/erc20-flashmint/tests/erc20-flashloan.rs

+    Ok(())
+}
+
+// #[e2e::test]


Unused test, please make it work.

Ifechukwudaniel · 2024-11-27T00:21:47Z

I can handle them

Co-authored-by: Daniel Bigos <[email protected]>

Ifechukwudaniel added 3 commits November 13, 2024 21:31

chore: Implemented ERC3156FlashLender and ERC3156FlashBorrower

ab91bbe

chore: removed lender

7862012

chore: flashmint

a7c0160

Ifechukwudaniel requested review from bidzyyys, qalisander and 0xNeshi as code owners November 14, 2024 04:27

Merge branch 'main' into erc20flashMint

70d67a1

0xNeshi reviewed Nov 14, 2024

View reviewed changes

Ifechukwudaniel and others added 18 commits November 14, 2024 12:08

chore : cargo format

47053bc

Update contracts/src/token/erc20/extensions/flashmint.rs

6ea75eb

Co-authored-by: Nenad <[email protected]>

Update contracts/src/token/erc20/extensions/flashmint.rs

53ee21a

Co-authored-by: Nenad <[email protected]>

chore: added docs for IERC3156FlashBorrower

3bd25cf

chore: fixed tab

chore: docs

b9cce5d

Merge branch 'main' into erc20flashMint

03f6f38

Create erc20-flashloan.adoc

6aa5b6d

Merge pull request #1 from Ifechukwudaniel/patch-1

ebee8d5

Create erc20-flashloan.adoc

chore: removed flashlaon and smaller changes

55672f6

chore: cargo format

626ae03

chore: abi and constructor

f8cdcf2

chore: flashloan example setup

85e62b1

chore: changed erc20FlashMint to erc20FlashMint

5feeb90

chore: erc20flashmint example

47aad90

chore: mock, abi and initial e2e test

99a8089

chore: created Erc3156FlashBorrowerMock

1b20ea6

chore: minor changes

4d08485

chore: cargo fmt fix

c3271bf

chore: fixes

0xNeshi reviewed Nov 18, 2024

View reviewed changes

Ifechukwudaniel and others added 7 commits November 19, 2024 16:23

Merge branch 'main' into erc20flashMint

fc229cd

chore: uint test

890807d

smaller chages

chore: smaller fixes

ea3a9b3

Merge branch 'main' into erc20flashMint

93fb0c0

chore : e2e flashmints

53afee1

chore: smaller changes

e464bf2

Merge branch 'main' into erc20flashMint

51dc8f1

bidzyyys reviewed Nov 25, 2024

View reviewed changes

bidzyyys and others added 5 commits November 25, 2024 15:22

Merge branch 'main' into erc20flashMint

c2fac88

chore: smaller changes

5b27cc8

chore: changes

258a081

Merge remote-tracking branch 'origin/erc20flashMint' into commites

4c660b3

Merge branch 'main' into erc20flashMint

857f437

Ifechukwudaniel and others added 3 commits November 27, 2024 14:45

Update contracts/src/token/erc20/utils/borrower.rs

170705c

Co-authored-by: Daniel Bigos <[email protected]>

chore: removed map_err

407f1be

Merge branch 'main' into erc20flashMint

46461b3

		import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v5.1.0/contracts/interfaces/IERC3156FlashBorrower.sol";


		contract ERC3156FlashBorrowerMock is IERC3156FlashBorrower {

		@@ -0,0 +1,326 @@
		//! Optional Flashloan extension of the ERC-20 standard.

Erc20flash mint #407

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Erc20flash mint #407

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Ifechukwudaniel commented Nov 14, 2024

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Ifechukwudaniel commented Nov 27, 2024

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