Add a Custom Curve Pool Implementation Handling RAI #144

stefanionescu · 2021-10-20T16:02:05Z

What I did

Related issue: N/A

This PR adds a new type of Curve pool meant to handle stablecoins with a floating target price such as RAI.

How I did it

All changes and test descriptions can be found here.

How to verify it

You can verify the Quantstamp audit for this pool which can be seen here. Please note QSP#2 that mentions the pool does not update and fetch RAI's redemption price prior to every action because it would be expensive to do so. This means we have to mention this tradeoff to the community.

…rate

Pool rai

locking pragma for RAI pool

michwill · 2021-11-02T11:13:17Z

contracts/pools/rai/StableSwapRAI.vy

+N_COINS: constant(int128) = 2
+MAX_COIN: constant(int128) = N_COINS - 1
+REDEMPTION_COIN: constant(int128) = 0  # Index of asset with moving target redemption price
+REDMPTION_PRICE_SCALE: constant(int128) = 10 ** 9


I think better to have it being uint256

michwill · 2021-11-02T11:14:26Z

contracts/pools/rai/StableSwapRAI.vy

+        if i == REDEMPTION_COIN:
+            x = xp[i] + (_dx * self._get_scaled_redemption_price() / PRECISION)
+        else:
+            x = xp[i] + _dx


I guess this line is never reached if we have 2-coin pools right? So it is just in case ever a 3-coin pool is needed?

michwill · 2021-11-02T11:15:42Z

contracts/pools/rai/StableSwapRAI.vy

+
+@pure
+@internal
+def _xp_mem(_redemption_price: uint256, _vp_rate: uint256, _balances: uint256[N_COINS]) -> uint256[N_COINS]:


Probably can pass a rates array instead. This is hardcoded for 2-coin pools (which is fine) but also makes it a bit more verbose. Though doesn't do anything bad also

michwill · 2021-11-02T11:33:15Z

tests/pools/rai/integration/test_redemption_rate_handling.py

+    def rule_adjust_redemption_price(self, st_red_prices):
+        self.redemption_price_snap.setRedemptionPriceSnap(st_red_prices)
+
+    def invariant_check_virtual_price(self):


This checks only base virtual price. It will never go down, that's checked in other places. But the actual swap virtual price could!

And this makes it hard to test. Price going down inevitably leads to a loss, but in principle price going up should lead to virtual_price going up: maybe that's something which can be tested.

michwill · 2021-11-02T11:40:29Z

One more significant thing. Virtual price here is not an invariant and it involves price of RAI going up or down. It will show crazy high positive or crazy high negative apy which is no good. So describing what can be done...

michwill · 2021-11-02T11:48:14Z

Can make another kind of virtual_price (virtual_price_2?) which can (similarly to virtual pool prices) defined as:

balances: uint256[2] = self.balances
xp: uint256[2] = self._xp()
virtual_price_2 = 2 * sqrt(balances[0] * xp[1]) / token_amount

Needs to use sqrt (which can use either decimal data type which sucks, or be implemented from scratch which we do in crypto contracts).

virtual_price_2 will be close to something between the price of LP token in USD and in RAI which makes sense. And that will behave really smoother than the traditional virtual price.

And still, that stays somewhat an experiment

michwill · 2021-11-02T15:55:31Z

Ok, more stable is:

virtual_price_2 = virtual_price / sqrt(redemption_price)

who would have thought huh?

stefanionescu · 2021-11-17T02:10:25Z

We did some improvements to the RAI pool code here (as advised by Michael):

reflexer-labs#5 (comment)

These also need a final thumbs up so we can merge here as well.

halito22

thank you I am sorry for the delay

halito22 · 2021-11-17T02:15:44Z

contracts/pools/rai/DepositRAI.vy

@@ -0,0 +1,376 @@
+# @version 0.2.12
+"""


halito22 · 2021-11-17T02:16:33Z

tests/pools/rai/unitary/test_rp_caching.py

@@ -0,0 +1,20 @@
+import pytest


halito22 · 2021-11-17T02:17:10Z

tests/pools/rai/unitary/test_rp_caching.py

+import pytest
+
+pytestmark = pytest.mark.usefixtures("add_initial_liquidity")
+


halito22 · 2021-11-17T02:17:54Z

tests/pools/rai/unitary/test_remove_liquidity_moving_rp.py

+        assert coin.balanceOf(swap) == amount / 2
+
+    assert pool_token.balanceOf(alice) == n_coins * 10 ** 18 * base_amount / 2
+    assert pool_token.totalSupply() == n_coins * 10 ** 18 * base_amount / 2


halito22 · 2021-11-17T02:18:19Z

tests/pools/rai/unitary/test_remove_liquidity_imbalance_moving_rp.py

+
+    # Ensure the max burn moves with the redemption price to reflect the proportion of liquidity value removed
+    with brownie.reverts("Slippage screwed you"):
+        swap.remove_liquidity_imbalance(amounts, max_burn * 0.999, {"from": alice})


halito22 · 2021-11-17T02:22:47Z

contracts/testing/RedemptionPriceSnapMock.sol

+    function snappedRedemptionPrice() public view returns (uint256) {
+        return internalSnappedRedemptionPrice;
+    }
+}


halito22 · 2021-11-17T02:23:10Z

contracts/pools/rai/pooldata.json

+            "underlying_address": "0x6c3F90f043a72FA612cbac8115EE7e52BDe6E490"
+        }
+    ]
+}


halito22 · 2021-11-17T02:24:00Z

contracts/pools/rai/README.md

+
+* `DAI`: [0x6b175474e89094c44da98b954eedeac495271d0f](https://etherscan.io/address/0x6b175474e89094c44da98b954eedeac495271d0f)
+* `USDC`: [0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48](https://etherscan.io/address/0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48)
+* `USDT`: [0xdac17f958d2ee523a2206206994597c13d831ec7](https://etherscan.io/address/0xdac17f958d2ee523a2206206994597c13d831ec7)


halito22 · 2021-11-17T02:24:14Z

contracts/pools/rai/DepositRAI.vy

+
+    base_tokens: uint256 = CurveBase(self.base_pool).calc_token_amount(base_amounts, _is_deposit)
+    meta_amounts[MAX_COIN] = base_tokens
+


halito22 · 2021-11-17T02:25:01Z

.gitignore

@@ -1,6 +1,7 @@
 __pycache__
 .history
 .hypothesis/
+.idea/


halito22 · 2021-11-17T02:41:47Z

contracts/pools/rai/StableSwapRAI.vy

@@ -1,4 +1,4 @@
-# @version ^0.2.12
+# @version 0.2.12


Curve review

halito22 · 2021-12-03T14:54:09Z

contracts/pools/rai/StableSwapRAI.vy

+N_COINS: constant(uint256) = 2
+MAX_COIN: constant(uint256) = N_COINS - 1
+REDEMPTION_COIN: constant(uint256) = 0  # Index of asset with moving target redemption price
+REDMPTION_PRICE_SCALE: constant(uint256) = 10 ** 9



halito22 · 2021-12-03T14:54:36Z

contracts/pools/rai/StableSwapRAI.vy


 FEE_DENOMINATOR: constant(uint256) = 10 ** 10
 PRECISION: constant(uint256) = 10 ** 18  # The precision to convert to
-BASE_N_COINS: constant(int128) = 3
+BASE_N_COINS: constant(uint256) = 3


This pool provides documentation for the pull request to adapt curve v1 Contracts so a non-peggie (such as RAI) and a peggie (such as UST) can be swapped as described at [gitcoin](https://gitcoin.co/issue/reflexer-labs/curve-contract/6/100027296).

Raiust pool is covered by all preexisting common tests, and I have added some specific test for moving redemption price.

The detailed Readme document to describe implementation.

Two Coin Pool with peggie and non-peggie, Raiust Pool

Gitcoin submission review

stobiewan and others added 7 commits September 14, 2021 09:23

feat: RAI pool, new meta pool customised to handle redemption rate

218168b

test: RAI pool, add pool specific tests focused on moving redemption …

a0ee346

…rate

docs: RAI pool, add temporary doc detailing changes made for RAI pool

314dde1

Merge pull request #3 from stobiewan/pool_rai

a6a29eb

Pool rai

Remove RAI readme

f6cf407

locking pragma for RAI pool

6c5d52e

Merge pull request #4 from reflexer-labs/audit

3104128

locking pragma for RAI pool

stefanionescu changed the title ~~Add the Custom RAI Curve Pool Implementation~~ Add a Custom Curve Pool Implementation Handling RAI Oct 20, 2021

michwill reviewed Nov 2, 2021

View reviewed changes

fabiohild added 7 commits November 3, 2021 00:03

changing state vars to uint256

f793ac7

Uniting _rates instead of single vars for each rate

291b16f

removing unreachable code on get_dy_underlying

016c7a6

Improving invariant_check_virtual_price test on RAI integration tests

6657b28

Curve review points

60824a3

updating virtual_price_2 formula

f6492b4

include sqrt in the contract, remove donate_admin_fees

0046953

halito22 approved these changes Nov 17, 2021

View reviewed changes

contracts/pools/rai/StableSwapRAI.vy

@@ -1,4 +1,4 @@

# @version ^0.2.12

# @version 0.2.12

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halito22 Nov 17, 2021

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good

halito22 approved these changes Nov 17, 2021

View reviewed changes

fabiohild and others added 2 commits November 17, 2021 13:28

fixing scaling issue on get_virtual_price_2

73397ec

Merge pull request #5 from reflexer-labs/curve-review

d52df33

Curve review

halito22 approved these changes Dec 3, 2021

View reviewed changes

didadi and others added 11 commits December 24, 2021 01:47

Test: Raiust pool, add specific test for moving redemption price

d8799bf

Raiust pool is covered by all preexisting common tests, and I have added some specific test for moving redemption price.

Test: Raiust pool, add specific test for moving redemption price

43f0ae7

Raiust pool is covered by all preexisting common tests, and I have added some specific test for moving redemption price.

Doc: Raiust pool, readme to describe implementation

19365c5

The detailed Readme document to describe implementation.

Merge pull request #7 from fs1028/master

9d44747

Two Coin Pool with peggie and non-peggie, Raiust Pool

renaming RATES, adding virtual_price_2

f1954a8

removing temp README

763fa6f

Merge pull request #8 from reflexer-labs/gitcoin-submission-review

087915e

Gitcoin submission review

Rename StableSwapRaiust.vy to StableSwapRaiUst.vy

b60d49c

Update README.md

c612bcf

Update README.md

2297ab0

Provide feedback

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Add a Custom Curve Pool Implementation Handling RAI #144

Add a Custom Curve Pool Implementation Handling RAI #144

stefanionescu commented Oct 20, 2021 •

edited

michwill Nov 2, 2021

michwill Nov 2, 2021

michwill Nov 2, 2021

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michwill commented Nov 2, 2021 •

edited

michwill commented Nov 2, 2021

michwill commented Nov 2, 2021

stefanionescu commented Nov 17, 2021

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halito22 Dec 3, 2021

halito22 Dec 3, 2021

		import pytest

		pytestmark = pytest.mark.usefixtures("add_initial_liquidity")


		base_tokens: uint256 = CurveBase(self.base_pool).calc_token_amount(base_amounts, _is_deposit)
		meta_amounts[MAX_COIN] = base_tokens

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stefanionescu commented Oct 20, 2021 • edited

What I did

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michwill commented Nov 2, 2021 • edited

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stefanionescu commented Oct 20, 2021 •

edited

michwill commented Nov 2, 2021 •

edited