feat: circulating supply helper

.github/workflows/ci.yaml

@@ -1,6 +1,6 @@
 name: CI Workflow
 
-on: [push, pull_request]
+on: [push]
 
 jobs:
 

contracts/StablecoinLens.vy

@@ -2,28 +2,67 @@
 
 from interfaces import IPegKeeper
 from interfaces import IController
+from interfaces import IControllerFactory
+from interfaces import IMonetaryPolicy
 
-MAX_CONTROLLERS: constant(uint256) = 50000  # TODO check actual number
-MAX_PEG_KEEPERS: constant(uint256) = 100  # TODO check actual number
+# bound from factory
+MAX_CONTROLLERS: constant(uint256) = 50000
+# bound from monetary policy
+MAX_PEG_KEEPERS: constant(uint256) = 1001
+# could have been any other controller
+WETH_CONTROLLER_IDX: constant(uint256) = 3
 
-controllers: DynArray[address, MAX_CONTROLLERS]
-peg_keepers: DynArray[address, MAX_PEG_KEEPERS]
+# the crvusd controller factory
+factory: immutable(IControllerFactory)
+
+
+@deploy
+def __init__(_factory: IControllerFactory):
+    factory = _factory
 
 
 @view
 @external
 def circulating_supply() -> uint256:
-    total_supply: uint256 = 0
+    """
+    @notice Compute the circulating supply for crvUSD, `totalSupply` is
+        incorrect since it takes into account all minted crvUSD (i.e. flashloans)
+    @dev This function sacrifices some gas to fetch peg keepers from a
+        unique source of truth to avoid having to manually maintain multiple
+        lists across several contracts.
+        For this reason we read the list of peg keepers contained in
+        the monetary policy returned by a controller in the factory.
+        factory -> weth controller -> monetary policy -> peg keepers
+    """
+
+    circulating_supply: uint256 = 0
+
+    # Fetch the weth controller (index 3) under the assumption that
+    # weth will always be a valid collateral for crvUSD, therefore its
+    # monetary policy should always be up to date.
+    controller: IController = staticcall factory.controllers(3)
+
+    # We obtain the address of the current monetary policy used by the
+    # weth controller because it contains a list of all the peg keepers.
+    monetary_policy: IMonetaryPolicy = staticcall controller.monetary_policy()
 
-    # TODO how to optimize this
-    for pk: address in self.peg_keepers:
-        if pk != empty(address):
-            total_supply += staticcall IPegKeeper(pk).debt()
+    # Iterate over the peg keepers (since it's a fixed size array we
+    # wait for a zero address to stop iterating).
+    for i: uint256 in range(MAX_PEG_KEEPERS):
+        pk: IPegKeeper = staticcall monetary_policy.peg_keepers(i)
+
+        if pk.address == empty(address):
+            # end of array
+            break
+
+        circulating_supply += staticcall pk.debt()
+
+    n_controllers: uint256 = staticcall factory.n_collaterals()
 
-    # TODO get correct value for this
-    n_controllers: uint256 = 0
     for i: uint256 in range(n_controllers, bound=MAX_CONTROLLERS):
-        controller: address = self.controllers[i]
-        total_supply += staticcall IController(controller).total_debt()
+        controller = staticcall factory.controllers(i)
+
+        # add crvUSD minted by controller
+        circulating_supply += staticcall controller.total_debt()
 
-    return total_supply
+    return circulating_supply

contracts/interfaces/IController.vyi

@@ -1,4 +1,15 @@
+# pragma version ~=0.4.0
+
+import IMonetaryPolicy
+
+
 @view
 @external
 def total_debt() -> uint256:
     ...
+
+
+@view
+@external
+def monetary_policy() -> IMonetaryPolicy:
+    ...

contracts/interfaces/IControllerFactory.vyi

@@ -0,0 +1,15 @@
+# pragma version ~=0.4.0
+
+import IController
+
+
+@external
+@view
+def controllers(i: uint256) -> IController:
+    ...
+
+
+@external
+@view
+def n_collaterals() -> uint256:
+    ...

contracts/interfaces/IMonetaryPolicy.vyi

@@ -0,0 +1,9 @@
+# pragma version ~=0.4.0
+
+import IPegKeeper
+
+
+@view
+@external
+def peg_keepers(i: uint256) -> IPegKeeper:
+    ...

contracts/interfaces/IPegKeeper.vyi

@@ -1,3 +1,5 @@
+# pragma version ~=0.4.0
+
 @view
 @external
 def debt() -> uint256:

contracts/interfaces/IStablecoinLens.vyi

@@ -1,4 +1,4 @@
-# Functions
+# pragma version ~=0.4.0
 
 @view
 @external

pyproject.toml

@@ -4,7 +4,6 @@ version = "0.1.0"
 description = ""
 authors = ["Curve.fi"]
 readme = "README.md"
-package-mode = false
 
 [tool.black]
 line-length = 100
@@ -14,11 +13,11 @@ target_version = ['py312']
 python = "^3.12.6"
 poetry = "^1.8.3"
 vyper = "0.4.0"
-titanoboa = { git = "https://github.com/vyperlang/titanoboa.git", branch = "master" }
+titanoboa = { git = "https://github.com/vyperlang/titanoboa.git", rev = "4768207288ec8fb23a4817ae193bd707ab9d1e8f" }
 snekmate = "0.1.0"
 
 [tool.poetry.group.dev.dependencies]
-mamushi = "0.0.4a1"
+mamushi = "0.0.4a3"
 pre-commit = "^3.8.0"
 black = "24.8.0"
 pytest = "^8.2.2"

tests/integration/conftest.py

@@ -0,0 +1,26 @@
+import os
+
+import boa
+import pytest
+
+boa.set_etherscan(api_key=os.getenv("ETHERSCAN_API_KEY"))
+
+
+@pytest.fixture(scope="module")
+def rpc_url():
+    return os.getenv("ETH_RPC_URL") or "https://rpc.ankr.com/eth"
+
+
+@pytest.fixture(scope="module", autouse=True)
+def forked_env(rpc_url):
+    boa.fork(rpc_url, block_identifier=18801970)
+
+
+@pytest.fixture(scope="module")
+def controller_factory():
+    return boa.from_etherscan("0xC9332fdCB1C491Dcc683bAe86Fe3cb70360738BC", "controller_factory")
+
+
+@pytest.fixture(scope="module")
+def lens(controller_factory):
+    return boa.load("contracts/StablecoinLens.vy", controller_factory)

tests/integration/test_fork_circulating_supply.py

@@ -0,0 +1,5 @@
+def test_fork_circulating_supply(lens):
+    # TODO mint more crvusd and make sure this increases accordingly
+    # TODO increase flashloan debt ceiling and make
+    #  sure supply doesn't increase
+    print("{:2e}".format(lens.circulating_supply()))

tests/mocks/MockController.vy

@@ -0,0 +1,14 @@
+# pragma version ~=0.4.0
+
+from contracts.interfaces import IController
+from contracts.interfaces import IMonetaryPolicy
+
+implements: IController
+
+_monetary_policy: address
+total_debt: public(uint256)
+
+@external
+@view
+def monetary_policy() -> IMonetaryPolicy:
+    return IMonetaryPolicy(self._monetary_policy)

tests/mocks/MockControllerFactory.vy

@@ -0,0 +1,18 @@
+# pragma version ~=0.4.0
+
+from contracts.interfaces import IControllerFactory
+from contracts.interfaces import IController
+
+implements: IControllerFactory
+
+_controllers: DynArray[IController, 10000]
+
+@external
+@view
+def controllers(i: uint256) -> IController:
+    return self._controllers[i]
+
+@external
+@view
+def n_collaterals() -> uint256:
+    return len(self._controllers)

tests/mocks/MockMonetaryPolicy.vy

@@ -0,0 +1,13 @@
+# pragma version ~=0.4.0
+
+from contracts.interfaces import IMonetaryPolicy
+from contracts.interfaces import IPegKeeper
+
+implements: IMonetaryPolicy
+
+peg_keeper: IPegKeeper
+
+@external
+@view
+def peg_keepers(i: uint256) -> IPegKeeper:
+    return self.peg_keeper

tests/unitary/conftest.py

@@ -36,9 +36,7 @@ def role_manager():
 def vault(vault_factory, crvusd, role_manager):
     vault_deployer = boa.load_partial("contracts/yearn/Vault.vy")
 
-    address = vault_factory.deploy_new_vault(
-        crvusd, "Staked crvUSD", "st-crvUSD", role_manager, 0
-    )
+    address = vault_factory.deploy_new_vault(crvusd, "Staked crvUSD", "st-crvUSD", role_manager, 0)
 
     return vault_deployer.at(address)