chore: update linting configuration (#177)

## Description

This PR revamps linting settings and adds linting to files in `script`
and `test`.
This led to the following changes:
- Updated `solhint` to the latest version. Most notably,
`no-unused-import` has been introduced.
- Ignored a few new rules coming from the update. This is mostly because
we don't want to touch `src/` yet, I expect these rules to be dropped
eventually.
- Created dedicated config files for linting tests and scrips.
(Unfortunately, I didn't find a way to make them depend on each other
without creating a dedicated NPM package for this purpose.)
- Enforce Solidity pragma `^0.8` in tests and scripts. There's no need
to be strict (mentioned in f64f5df).
- Updated `package.json` with the new linting commands; in particular,
they will be used in CI.
- Fixed a few linting issues.
- Removed `NonPayable.sol` (unused).

## Known issues

1. Linting relies on `package.json`, which will eventually be removed
from this repo.
2. The Solidity VSCode extension linting isn't using the same linter
version used in CI. For example, it signals `custom-errors` despite it
being disabled (but through `gas-custom-errors`)

## Things to keep in mind for the future

The following features (from [Solhint's issue
tracker](https://github.com/protofire/solhint/issues/)) would be
helpful:
- 359 (overrides in `.solhint.json`)
- 302 (extensible configs)
- 571 (enforce import ordering; this is being worked on!)
- 496 (`"no-empty-blocks": ["error", { "ignoreConstructors": true }]`)
- 588 (`no-duplicated-import`)

## Test Plan

CI.

.solhint.json

@@ -3,8 +3,10 @@
   "plugins": ["prettier"],
   "rules": {
     "compiler-version": "off",
-    "no-global-import": "off",
     "func-visibility": ["warn", { "ignoreConstructors": true }],
+    "gas-custom-errors": "off",
+    "immutable-vars-naming": "off",
+    "no-global-import": "off",
     "prettier/prettier": "error"
   }
 }

package.json

@@ -14,8 +14,10 @@
     "build": "yarn build:sol && yarn build:ts",
     "build:sol": "hardhat compile --force",
     "build:ts": "tsc && tsc -p tsconfig.lib.esm.json && tsc -p tsconfig.lib.commonjs.json",
-    "lint": "yarn lint:sol && yarn lint:ts",
-    "lint:sol": "solhint 'src/contracts/**/*.sol'",
+    "lint": "yarn lint:sol:src && yarn lint:ts && yarn lint:sol:test && yarn lint:sol:script",
+    "lint:sol:script": "solhint --max-warnings 0 --config ./script/.solhint.json 'script/**/*.sol'",
+    "lint:sol:src": "solhint --max-warnings 0 'src/**/*.sol'",
+    "lint:sol:test": "solhint --max-warnings 0 --config ./test/.solhint.json 'test/**/*.sol'",
     "lint:ts": "eslint --max-warnings 0 .",
     "test": "hardhat test",
     "test:ignored-in-coverage": "MOCHA_CONF='ignored in coverage' hardhat test",
@@ -77,7 +79,7 @@
     "prettier": "^2.8.7",
     "prettier-plugin-solidity": "^1.1.3",
     "sinon": "^15.0.3",
-    "solhint": "^3.4.1",
+    "solhint": "^5.0.0",
     "solhint-plugin-prettier": "^0.0.5",
     "solidity-coverage": "^0.8.2",
     "ts-node": "^10.9.1",

script/.solhint.json

@@ -0,0 +1,11 @@
+{
+  "extends": "solhint:recommended",
+  "rules": {
+    "compiler-version": ["warn", "^0.8"],
+    "func-visibility": ["warn", { "ignoreConstructors": true }],
+    "gas-custom-errors": "off",
+    "immutable-vars-naming": "off",
+    "no-console": "off",
+    "no-global-import": "off"
+  }
+}

script/TransferOwnership.s.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {console} from "forge-std/Script.sol";
 

script/interfaces/ERC173.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0
-pragma solidity >=0.7.6 <0.9.0;
+pragma solidity ^0.8;
 
 // Copied from:
 // <https://eips.ethereum.org/EIPS/eip-173#specification>

script/lib/NetworksJson.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {Script} from "forge-std/Script.sol";
 

test/.solhint.json

@@ -0,0 +1,16 @@
+{
+  "extends": "solhint:recommended",
+  "rules": {
+    "compiler-version": ["warn", "^0.8"],
+    "const-name-snakecase": "off",
+    "func-name-mixedcase": "off",
+    "func-visibility": ["warn", { "ignoreConstructors": true }],
+    "gas-custom-errors": "off",
+    "immutable-vars-naming": "off",
+    "no-global-import": "off",
+    "no-inline-assembly": "off",
+    "one-contract-per-file": "off",
+    "reason-string": "off",
+    "state-visibility": "off"
+  }
+}

test/GPv2AllowListAuthenticator/AddSolver.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {GPv2AllowListAuthentication} from "src/contracts/GPv2AllowListAuthentication.sol";
 

test/GPv2AllowListAuthenticator/Helper.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {Test} from "forge-std/Test.sol";
 

test/GPv2AllowListAuthenticator/InitializeManager.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {GPv2AllowListAuthentication} from "src/contracts/GPv2AllowListAuthentication.sol";
 

test/GPv2AllowListAuthenticator/IsSolver.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {Helper} from "./Helper.sol";
 

test/GPv2AllowListAuthenticator/RemoveSolver.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {GPv2AllowListAuthentication} from "src/contracts/GPv2AllowListAuthentication.sol";
 

test/GPv2AllowListAuthenticator/SetManager.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {GPv2AllowListAuthentication} from "src/contracts/GPv2AllowListAuthentication.sol";
 

test/GPv2Interaction/Execute.t.sol

@@ -1,10 +1,12 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {Helper} from "./Helper.sol";
 
 import {GPv2Interaction} from "src/contracts/libraries/GPv2Interaction.sol";
 
+// Intentionally empty contract.
+// solhint-disable-next-line no-empty-blocks
 contract NonPayable {}
 
 contract Transfer is Helper {

test/GPv2Interaction/Helper.sol

@@ -1,6 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity >=0.7.6 <0.9.0;
-pragma abicoder v2;
+pragma solidity ^0.8;
 
 import {Test} from "forge-std/Test.sol";
 

test/GPv2Interaction/Selector.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {Helper} from "./Helper.sol";
 

test/GPv2SafeERC20/Helper.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {Test} from "forge-std/Test.sol";
 

test/GPv2SafeERC20/Transfer.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {IERC20} from "src/contracts/interfaces/IERC20.sol";
 

test/GPv2SafeERC20/TransferFrom.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {IERC20} from "src/contracts/interfaces/IERC20.sol";
 

test/GPv2Signing/Helper.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {IERC20} from "src/contracts/interfaces/IERC20.sol";
 import {GPv2Signing} from "src/contracts/mixins/GPv2Signing.sol";

test/GPv2VaultRelayer/BatchSwapWithFee.FeeTransfer.t.sol

@@ -1,9 +1,7 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
 pragma solidity ^0.8.0;
 
-import {
-    GPv2VaultRelayer, GPv2Transfer, IERC20, IVault, GPv2Transfer, GPv2Order
-} from "src/contracts/GPv2VaultRelayer.sol";
+import {GPv2Transfer, IERC20, IVault, GPv2Transfer, GPv2Order} from "src/contracts/GPv2VaultRelayer.sol";
 
 import {BatchSwapWithFeeHelper} from "./Helper.sol";
 

test/GPv2VaultRelayer/Helper.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {Test} from "forge-std/Test.sol";
 

test/GPv2VaultRelayer/TransferFromAccounts.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {IERC20, IVault, GPv2Transfer, GPv2Order} from "src/contracts/GPv2VaultRelayer.sol";
 

test/libraries/Bytecode.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {Vm} from "forge-std/Test.sol";
 import {Bytes} from "./Bytes.sol";

test/libraries/Bytes.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 library Bytes {
     function slice(bytes memory d, uint256 offset, uint256 length) internal pure returns (bytes memory) {

test/libraries/Order.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {IERC20, GPv2Order} from "src/contracts/libraries/GPv2Order.sol";
 import {GPv2Trade} from "src/contracts/libraries/GPv2Trade.sol";

test/libraries/Settlement.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {GPv2Settlement} from "src/contracts/GPv2Settlement.sol";
 import {SettlementEncoder} from "./encoders/SettlementEncoder.sol";

test/libraries/Sign.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {Vm} from "forge-std/Test.sol";
 

test/libraries/Trade.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {IERC20, GPv2Order, GPv2Trade, GPv2Signing} from "src/contracts/mixins/GPv2Signing.sol";
 import {Sign} from "./Sign.sol";

test/libraries/encoders/SettlementEncoder.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {Vm} from "forge-std/Test.sol";
 
@@ -106,6 +106,7 @@ library SettlementEncoder {
 
         // All the order refunds are encoded in the POST interactions so we take some liberty and
         // use a short variable to represent the POST stage.
+        // solhint-disable-next-line var-name-mixedcase
         uint256 POST = uint256(InteractionStage.POST);
         GPv2Interaction.Data[] memory postInteractions =
             new GPv2Interaction.Data[](state.interactions[POST].length + r.length);

test/libraries/encoders/SwapEncoder.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {Vm} from "forge-std/Test.sol";
 

test/libraries/encoders/TokenRegistry.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {IERC20, GPv2Order} from "src/contracts/libraries/GPv2Order.sol";
 

test/reader/AllowListStorageReader.t.sol

@@ -1,6 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-
-pragma solidity ^0.8.24;
+pragma solidity ^0.8;
 
 import {Test} from "forge-std/Test.sol";
 

test/reader/SettlementStorageReader.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {Test} from "forge-std/Test.sol";
 

test/reader/StorageAccessible.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {Test, Vm} from "forge-std/Test.sol";
 import {StorageAccessibleWrapper, ExternalStorageReader} from "./StorageAccessibleWrapper.sol";

test/reader/StorageAccessibleWrapper.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-only
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import "src/contracts/mixins/StorageAccessible.sol";
 
@@ -23,6 +23,7 @@ contract StorageAccessibleWrapper is StorageAccessible {
     mapping(uint256 => uint256) qux;
     FooBar foobar;
 
+    // solhint-disable-next-line no-empty-blocks
     constructor() {}
 
     function setFoo(uint256 foo_) public {

test/reader/StorageReadable.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {Test} from "forge-std/Test.sol";
 

test/reader/ViewStorageAccessible.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.0;
+pragma solidity ^0.8;
 
 import {Test} from "forge-std/Test.sol";
 

test/script/TransferOwnership.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {Test} from "forge-std/Test.sol";
 

test/script/lib/NetworksJson.t.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
-pragma solidity ^0.8.26;
+pragma solidity ^0.8;
 
 import {Test} from "forge-std/Test.sol";
 

test/src/ERC20PresetPermit.sol

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
+// solhint-disable-next-line compiler-version
 pragma solidity ^0.7.6;
 
 import "@openzeppelin/contracts/drafts/ERC20Permit.sol";

test/src/EventEmitter.sol

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
+// solhint-disable-next-line compiler-version
 pragma solidity >=0.7.6 <0.9.0;
 
 contract EventEmitter {

test/src/FeeClaimingERC20.sol

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: MIT
+// solhint-disable-next-line compiler-version
 pragma solidity ^0.7.6;
 
 import "@openzeppelin/contracts/presets/ERC20PresetMinterPauser.sol";

test/src/GPv2AllowListAuthenticationV2.sol

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
+// solhint-disable-next-line compiler-version
 pragma solidity >=0.7.6 <0.9.0;
 
 import "src/contracts/GPv2AllowListAuthentication.sol";

test/src/GPv2OrderTestInterface.sol

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
+// solhint-disable-next-line compiler-version
 pragma solidity >=0.7.6 <0.9.0;
 pragma abicoder v2;
 

test/src/GPv2SettlementTestInterface.sol

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
+// solhint-disable-next-line compiler-version
 pragma solidity >=0.7.6 <0.9.0;
 pragma abicoder v2;
 

test/src/GPv2SigningTestInterface.sol

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
+// solhint-disable-next-line compiler-version
 pragma solidity >=0.7.6 <0.9.0;
 pragma abicoder v2;
 

test/src/GPv2TradeTestInterface.sol

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
+// solhint-disable-next-line compiler-version
 pragma solidity >=0.7.6 <0.9.0;
 pragma abicoder v2;
 

test/src/GPv2TransferTestInterface.sol

@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: LGPL-3.0-or-later
+// solhint-disable-next-line compiler-version
 pragma solidity >=0.7.6 <0.9.0;
 pragma abicoder v2;