feat: Add StdConstants library (#654)

Fixes #267. Gathers up all
constants used throughout forge-std in a single library so they are
easier to access.

~~The refactoring around the constants is minimal, it's mostly
replacements of arbitrary values with references to the new library. No
changes are visible from the outside, the 3 constants removed from
`StdUtil` were private. Many more refactorings, like dropping other
private constants that are used more than once or are variations about
`type(uintXXX).max`, may be done in separate PRs.~~

Author: CodeSandwich

src/Base.sol

@@ -5,19 +5,26 @@ import {StdStorage} from "./StdStorage.sol";
 import {Vm, VmSafe} from "./Vm.sol";
 
 abstract contract CommonBase {
-    // Cheat code address, 0x7109709ECfa91a80626fF3989D68f67F5b1DD12D.
-    address internal constant VM_ADDRESS = address(uint160(uint256(keccak256("hevm cheat code"))));
-    // console.sol and console2.sol work by executing a staticcall to this address.
+    /// @dev Cheat code address.
+    /// Calculated as `address(uint160(uint256(keccak256("hevm cheat code"))))`.
+    address internal constant VM_ADDRESS = 0x7109709ECfa91a80626fF3989D68f67F5b1DD12D;
+    /// @dev console.sol and console2.sol work by executing a staticcall to this address.
+    /// Calculated as `address(uint160(uint88(bytes11("console.log"))))`.
     address internal constant CONSOLE = 0x000000000000000000636F6e736F6c652e6c6f67;
-    // Used when deploying with create2, https://github.com/Arachnid/deterministic-deployment-proxy.
+    /// @dev Used when deploying with create2.
+    /// Taken from https://github.com/Arachnid/deterministic-deployment-proxy.
     address internal constant CREATE2_FACTORY = 0x4e59b44847b379578588920cA78FbF26c0B4956C;
-    // Default address for tx.origin and msg.sender, 0x1804c8AB1F12E6bbf3894d4083f33e07309d1f38.
-    address internal constant DEFAULT_SENDER = address(uint160(uint256(keccak256("foundry default caller"))));
-    // Address of the test contract, deployed by the DEFAULT_SENDER.
+    /// @dev The default address for tx.origin and msg.sender.
+    /// Calculated as `address(uint160(uint256(keccak256("foundry default caller"))))`.
+    address internal constant DEFAULT_SENDER = 0x1804c8AB1F12E6bbf3894d4083f33e07309d1f38;
+    /// @dev The address of the first contract `CREATE`d by a running test contract.
+    /// When running tests, each test contract is `CREATE`d by `DEFAULT_SENDER` with nonce 1.
+    /// Calculated as `VM.computeCreateAddress(VM.computeCreateAddress(DEFAULT_SENDER, 1), 1)`.
     address internal constant DEFAULT_TEST_CONTRACT = 0x5615dEB798BB3E4dFa0139dFa1b3D433Cc23b72f;
-    // Deterministic deployment address of the Multicall3 contract.
+    /// @dev Deterministic deployment address of the Multicall3 contract.
+    /// Taken from https://www.multicall3.com.
     address internal constant MULTICALL3_ADDRESS = 0xcA11bde05977b3631167028862bE2a173976CA11;
-    // The order of the secp256k1 curve.
+    /// @dev The order of the secp256k1 curve.
     uint256 internal constant SECP256K1_ORDER =
         115792089237316195423570985008687907852837564279074904382605163141518161494337;
 

src/Script.sol

@@ -10,6 +10,7 @@ import {console2} from "./console2.sol";
 import {safeconsole} from "./safeconsole.sol";
 import {StdChains} from "./StdChains.sol";
 import {StdCheatsSafe} from "./StdCheats.sol";
+import {StdConstants} from "./StdConstants.sol";
 import {stdJson} from "./StdJson.sol";
 import {stdMath} from "./StdMath.sol";
 import {StdStorage, stdStorageSafe} from "./StdStorage.sol";

src/StdConstants.sol

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.6.2 <0.9.0;
+
+import {IMulticall3} from "./interfaces/IMulticall3.sol";
+import {Vm} from "./Vm.sol";
+
+library StdConstants {
+    /// @dev Cheat code address.
+    /// Calculated as `address(uint160(uint256(keccak256("hevm cheat code"))))`.
+    Vm internal constant VM = Vm(0x7109709ECfa91a80626fF3989D68f67F5b1DD12D);
+    /// @dev console.sol and console2.sol work by executing a staticcall to this address.
+    /// Calculated as `address(uint160(uint88(bytes11("console.log"))))`.
+    address internal constant CONSOLE = 0x000000000000000000636F6e736F6c652e6c6f67;
+    /// @dev Used when deploying with create2.
+    /// Taken from https://github.com/Arachnid/deterministic-deployment-proxy.
+    address internal constant CREATE2_FACTORY = 0x4e59b44847b379578588920cA78FbF26c0B4956C;
+    /// @dev The default address for tx.origin and msg.sender.
+    /// Calculated as `address(uint160(uint256(keccak256("foundry default caller"))))`.
+    address internal constant DEFAULT_SENDER = 0x1804c8AB1F12E6bbf3894d4083f33e07309d1f38;
+    /// @dev The address of the first contract `CREATE`d by a running test contract.
+    /// When running tests, each test contract is `CREATE`d by `DEFAULT_SENDER` with nonce 1.
+    /// Calculated as `VM.computeCreateAddress(VM.computeCreateAddress(DEFAULT_SENDER, 1), 1)`.
+    address internal constant DEFAULT_TEST_CONTRACT = 0x5615dEB798BB3E4dFa0139dFa1b3D433Cc23b72f;
+    /// @dev Deterministic deployment address of the Multicall3 contract.
+    /// Taken from https://www.multicall3.com.
+    IMulticall3 internal constant MULTICALL3_ADDRESS = IMulticall3(0xcA11bde05977b3631167028862bE2a173976CA11);
+    /// @dev The order of the secp256k1 curve.
+    uint256 internal constant SECP256K1_ORDER =
+        115792089237316195423570985008687907852837564279074904382605163141518161494337;
+}

src/Test.sol

@@ -13,6 +13,7 @@ import {safeconsole} from "./safeconsole.sol";
 import {StdAssertions} from "./StdAssertions.sol";
 import {StdChains} from "./StdChains.sol";
 import {StdCheats} from "./StdCheats.sol";
+import {StdConstants} from "./StdConstants.sol";
 import {stdError} from "./StdError.sol";
 import {StdInvariant} from "./StdInvariant.sol";
 import {stdJson} from "./StdJson.sol";

test/CommonBase.t.sol

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.7.0 <0.9.0;
+
+import {CommonBase} from "../src/Base.sol";
+import {StdConstants} from "../src/StdConstants.sol";
+import {Test} from "../src/Test.sol";
+
+contract CommonBaseTest is Test {
+    function testVmAddressValue() public pure {
+        assertEq(VM_ADDRESS, address(StdConstants.VM));
+    }
+
+    function testConsoleValue() public pure {
+        assertEq(CONSOLE, StdConstants.CONSOLE);
+    }
+
+    function testCreate2FactoryValue() public pure {
+        assertEq(CREATE2_FACTORY, StdConstants.CREATE2_FACTORY);
+    }
+
+    function testDefaultSenderValue() public pure {
+        assertEq(DEFAULT_SENDER, StdConstants.DEFAULT_SENDER);
+    }
+
+    function testDefaultTestContractValue() public pure {
+        assertEq(DEFAULT_TEST_CONTRACT, StdConstants.DEFAULT_TEST_CONTRACT);
+    }
+
+    function testMulticall3AddressValue() public pure {
+        assertEq(MULTICALL3_ADDRESS, address(StdConstants.MULTICALL3_ADDRESS));
+    }
+
+    function testSecp256k1OrderValue() public pure {
+        assertEq(SECP256K1_ORDER, StdConstants.SECP256K1_ORDER);
+    }
+
+    function testUint256MaxValue() public pure {
+        assertEq(UINT256_MAX, type(uint256).max);
+    }
+
+    function testVmValue() public pure {
+        assertEq(address(vm), address(StdConstants.VM));
+    }
+}

test/StdConstants.t.sol

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.7.0 <0.9.0;
+
+import {StdConstants} from "../src/StdConstants.sol";
+import {Test} from "../src/Test.sol";
+
+contract StdConstantsTest is Test {
+    function testVm() public view {
+        assertEq(StdConstants.VM.getBlockNumber(), 1);
+    }
+
+    function testVmDerivation() public pure {
+        assertEq(address(StdConstants.VM), address(uint160(uint256(keccak256("hevm cheat code")))));
+    }
+
+    function testConsoleDerivation() public pure {
+        assertEq(StdConstants.CONSOLE, address(uint160(uint88(bytes11("console.log")))));
+    }
+
+    function testDefaultSender() public view {
+        assertEq(StdConstants.DEFAULT_SENDER, msg.sender);
+    }
+
+    function testDefaultSenderDerivation() public pure {
+        assertEq(StdConstants.DEFAULT_SENDER, address(uint160(uint256(keccak256("foundry default caller")))));
+    }
+
+    function testDefaultTestContract() public {
+        assertEq(StdConstants.DEFAULT_TEST_CONTRACT, address(new Dummy()));
+    }
+
+    function testDefaultTestContractDerivation() public view {
+        assertEq(address(this), StdConstants.VM.computeCreateAddress(StdConstants.DEFAULT_SENDER, 1));
+        assertEq(StdConstants.DEFAULT_TEST_CONTRACT, StdConstants.VM.computeCreateAddress(address(this), 1));
+    }
+}
+
+contract Dummy {}