Add custom linting rules (#4132)

Co-authored-by: Francisco Giordano <fg@frang.io>
Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>

scripts/solhint-custom/index.js

@@ -0,0 +1,84 @@
+const path = require('path');
+const minimatch = require('minimatch');
+
+// Files matching these patterns will be ignored unless a rule has `static global = true`
+const ignore = ['contracts/mocks/**/*', 'test/**/*'];
+
+class Base {
+  constructor(reporter, config, source, fileName) {
+    this.reporter = reporter;
+    this.ignored = this.constructor.global || ignore.some(p => minimatch(path.normalize(fileName), p));
+    this.ruleId = this.constructor.ruleId;
+    if (this.ruleId === undefined) {
+      throw Error('missing ruleId static property');
+    }
+  }
+
+  error(node, message) {
+    if (!this.ignored) {
+      this.reporter.error(node, this.ruleId, message);
+    }
+  }
+}
+
+module.exports = [
+  class extends Base {
+    static ruleId = 'interface-names';
+
+    ContractDefinition(node) {
+      if (node.kind === 'interface' && !/^I[A-Z]/.test(node.name)) {
+        this.error(node, 'Interface names should have a capital I prefix');
+      }
+    }
+  },
+
+  class extends Base {
+    static ruleId = 'private-variables';
+
+    VariableDeclaration(node) {
+      const constantOrImmutable = node.isDeclaredConst || node.isImmutable;
+      if (node.isStateVar && !constantOrImmutable && node.visibility !== 'private') {
+        this.error(node, 'State variables must be private');
+      }
+    }
+  },
+
+  class extends Base {
+    static ruleId = 'leading-underscore';
+
+    VariableDeclaration(node) {
+      if (node.isDeclaredConst) {
+        if (/^_/.test(node.name)) {
+          // TODO: re-enable and fix
+          // this.error(node, 'Constant variables should not have leading underscore');
+        }
+      } else if (node.visibility === 'private' && !/^_/.test(node.name)) {
+        this.error(node, 'Non-constant private variables must have leading underscore');
+      }
+    }
+
+    FunctionDefinition(node) {
+      if (node.visibility === 'private' || (node.visibility === 'internal' && node.parent.kind !== 'library')) {
+        if (!/^_/.test(node.name)) {
+          this.error(node, 'Private and internal functions must have leading underscore');
+        }
+      }
+      if (node.visibility === 'internal' && node.parent.kind === 'library') {
+        if (/^_/.test(node.name)) {
+          this.error(node, 'Library internal functions should not have leading underscore');
+        }
+      }
+    }
+  },
+
+  // TODO: re-enable and fix
+  // class extends Base {
+  //   static ruleId = 'no-external-virtual';
+  //
+  //   FunctionDefinition(node) {
+  //     if (node.visibility == 'external' && node.isVirtual) {
+  //       this.error(node, 'Functions should not be external and virtual');
+  //     }
+  //   }
+  // },
+];

scripts/solhint-custom/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "solhint-plugin-openzeppelin",
+  "private": true
+}