Long Tail contracts

Long Tail is Arbitrum's cheapest and most rewarding AMM.

Deployments

Superposition Testnet

AMM contract deployments

Deployment name	Deployment address
Long Tail AMM	0x839c5cf32d9Bc2CD46027691d2941410251ED557
Long Tail NFT manager	0xC96F6A050382d4aA73fd91f7A4D02aB8E5654338

Useful testing token deployments

Deployment name	Deployment address
fUSDC	0xA8EA92c819463EFbEdDFB670FEfC881A480f0115
WETH	0xde104342B32BCa03ec995f999181f7Cf1fFc04d7
USDC	0x6437fdc89cED41941b97A9f1f8992D88718C81c5
WSPN	0x22b9fa698b68bBA071B513959794E9a47d19214c

Access graph

A publicly available graph for Superposition Testnet is available. It includes documentation. https://testnet-graph.long.so.

Errors

Currently, to save on space, errors generated by the contract are terse. Decode the hex to the appropriate error in this table:

No	Hex	Explanation
0	0x00	Denominator is 0
1	0x01	Result is U256::MAX
2	0x02	Sqrt price is 0
3	0x03	Sqrt price is less than or equal to quotient
4	0x04	Can not get most significant bit or least significant bit on zero value
5	0x05	Liquidity is 0
6	0x06	require((product = amount * sqrtPX96) / amount == sqrtPX96 && numerator1 > product);
7	0x07	Denominator is less than or equal to prod_1
8	0x08	Liquidity Sub
9	0x09	Liquidity Add
10	0x0a	The given tick must be less than, or equal to, the maximum tick
11	0x0b	Second inequality must be < because the price can never reach the price at the max tick
12	0x0c	Overflow when casting to U160
13	0x0d	Liquidity higher than max
14	0x0e	Fee growth sub overflow
15	0x0f	ERC20 call reverted
16	0x10	ERC20 call reverted with no data
17	0x11	Pool is already initialised
18	0x12	Contract is already initialised
19	0x13	Price limit too high
20	0x14	Price limit too low
21	0x15	Checked abs called on an unexpected positive number
22	0x16	Checked abs called on an unexpected negative number
23	0x17	Checked abs called on uint.min
24	0x18	Fee result too high
25	0x19	Swap result too high
26	0x1a	Internal swap amounts not matched
27	0x1b	Internal swap result was positive
28	0x1c	Minimum out not reached
29	0x1d	Only the position owner can use this
30	0x1e	Only the NFT manager can use this
31	0x1f	Only the Seawater admin can use this
32	0x20	Operation unavailable when the pool is disabled

If more bytes are in the error, then the issue was produced by the ERC20 token. Convert any error types to their keccak form to see. For example, an allowance error might be hard to unpack, and it'll be several bytes.g

Security

Security instructions

Contributors

Building

Superposition AMM is a diamond-like contract, with the frontend to access the Stylus diamond facets implemented in Solidity. So, Stylus is needed with Rust for the implementation contracts, and Foundry is needed to compile the contract.

To save on contract size, and to reduce gas overhead, this contract stores the addresses of the swap router, and the admin address, at compile-time.

So these variables must set at compile-time, like so:

Build variables

Name	Description
`FLU_SEAWATER_PERMIT2_ADDR`	Uniswap Permit2 router
`FLU_SEAWATER_FUSDC_ADDR`	USDC Super Asset to route every trade through

Build dependencies

Name	Source
Rust (nightly version)	Installer
Cargo Stylus subcommand	Repo
Foundry	Installer
Make	`build-essentials` if you're on Linux

Build process

make build

Testing

Testing is done either on-chain with the live Ethers-powered environment (at the time of writing, there is no native on-chain testing with a forking suite), or via a hosted test using cargo features with the testing flag.

Testing dependencies

Name	Source
Node	Website
NPM	Website
Nitro testnode	Repo

Testing the local environment using Ethers is the process of:

Deploying a local Stylus testnode.
Running the ethers test suite.

Running the Ethers test suite is as simple as running ./tests.sh, which will also run tests on the host environment with stubbed out ERC20.

Running a local testnode

Clone the Nitro repo with submodules on the stylus branch.
Run the testing script ./test-node.bash --init. This will run the Stylus suite using Docker Compose, and make it available locally.

Testing process

./tests.sh

Cargo test tracing

Some of the cargo tests have optional logging, which might help with debugging. To see these logs, enable the testing-dbg-<test> feature and run the tests without capturing stdout, ie cargo test --features=testing,testing-dbg-erc20 -- --nocapture.

Testing tools are available with the with_storage macro, which lets you set slots and maximum balances for ERC20 transfers. Reproducing on-chain transactions is possible by using a tracer on the chain the transaciton took place, then examining the storage slots that were accessed (perhaps by looking at SLOADs), and setting it explicitly with the macro.

Name	Description
`SEAWATER_PROXY_ADMIN`	Address that's permitted to administrate the code, including deploying updates, and creating pools.
`STYLUS_ENDPOINT`	URL to access the Stylus node.
`STYLUS_PRIVATE_KEY`	Private key to use for deployment.
`FLU_SEAWATER_FUSDC_ADDR`	Super USDC address to use as the base asset for each pool.

Long Tail AMM contracts docs