Add internal rule that enforces valid default options

Author: FloEdelmann

Diff for: eslint-internal-rules/no-invalid-meta-default-options.js

@@ -0,0 +1,156 @@
+/**
+ * @fileoverview Internal rule to enforce valid default options.
+ * @author Flo Edelmann
+ */
+
+'use strict'
+
+const Ajv = require('ajv')
+const metaSchema = require('ajv/lib/refs/json-schema-draft-04.json')
+
+// from https://github.com/eslint/eslint/blob/main/lib/shared/ajv.js
+const ajv = new Ajv({
+  meta: false,
+  useDefaults: true,
+  validateSchema: false,
+  missingRefs: 'ignore',
+  verbose: true,
+  schemaId: 'auto'
+})
+ajv.addMetaSchema(metaSchema)
+ajv._opts.defaultMeta = metaSchema.id
+
+// from https://github.com/eslint/eslint/blob/main/lib/config/flat-config-helpers.js
+const noOptionsSchema = Object.freeze({
+  type: 'array',
+  minItems: 0,
+  maxItems: 0
+})
+function getRuleOptionsSchema(schema) {
+  if (schema === false || typeof schema !== 'object' || schema === null) {
+    return null
+  }
+
+  if (!Array.isArray(schema)) {
+    return schema
+  }
+
+  if (schema.length === 0) {
+    return { ...noOptionsSchema }
+  }
+
+  return {
+    type: 'array',
+    items: schema,
+    minItems: 0,
+    maxItems: schema.length
+  }
+}
+
+/**
+ * @param {RuleContext} context
+ * @param {ASTNode} node
+ * @returns {any}
+ */
+function getNodeValue(context, node) {
+  try {
+    // eslint-disable-next-line no-eval
+    return eval(context.getSourceCode().getText(node))
+  } catch (error) {
+    return undefined
+  }
+}
+
+/**
+ * Gets the property of the Object node passed in that has the name specified.
+ *
+ * @param {string} propertyName Name of the property to return.
+ * @param {ASTNode} node The ObjectExpression node.
+ * @returns {ASTNode} The Property node or null if not found.
+ */
+function getPropertyFromObject(propertyName, node) {
+  if (node && node.type === 'ObjectExpression') {
+    for (const property of node.properties) {
+      if (property.type === 'Property' && property.key.name === propertyName) {
+        return property
+      }
+    }
+  }
+  return null
+}
+
+module.exports = {
+  meta: {
+    type: 'problem',
+    docs: {
+      description: 'enforce correct use of `meta` property in core rules',
+      categories: ['Internal']
+    },
+    schema: [],
+    messages: {
+      defaultOptionsNotMatchingSchema:
+        'Default options do not match the schema.'
+    }
+  },
+
+  create(context) {
+    /** @type {ASTNode} */
+    let exportsNode
+
+    return {
+      AssignmentExpression(node) {
+        if (
+          node.left &&
+          node.right &&
+          node.left.type === 'MemberExpression' &&
+          node.left.object.name === 'module' &&
+          node.left.property.name === 'exports'
+        ) {
+          exportsNode = node.right
+        }
+      },
+
+      'Program:exit'() {
+        const metaProperty = getPropertyFromObject('meta', exportsNode)
+        if (!metaProperty) {
+          return
+        }
+
+        const metaSchema = getPropertyFromObject('schema', metaProperty.value)
+        const metaDefaultOptions = getPropertyFromObject(
+          'defaultOptions',
+          metaProperty.value
+        )
+
+        if (
+          !metaSchema ||
+          !metaDefaultOptions ||
+          metaDefaultOptions.value.type !== 'ArrayExpression'
+        ) {
+          return
+        }
+
+        const defaultOptions = getNodeValue(context, metaDefaultOptions.value)
+        const schema = getNodeValue(context, metaSchema.value)
+
+        if (!defaultOptions || !schema) {
+          return
+        }
+
+        let validate
+        try {
+          validate = ajv.compile(getRuleOptionsSchema(schema))
+        } catch (error) {
+          return
+        }
+
+        if (!validate(defaultOptions)) {
+          context.report({
+            node: metaDefaultOptions.value,
+            messageId: 'defaultOptionsNotMatchingSchema'
+          })
+        }
+      }
+    }
+  }
+}

Diff for: eslint.config.js

@@ -35,6 +35,7 @@ module.exports = [
       internal: {
         rules: {
           'no-invalid-meta': require('./eslint-internal-rules/no-invalid-meta'),
+          'no-invalid-meta-default-options': require('./eslint-internal-rules/no-invalid-meta-default-options'),
           'no-invalid-meta-docs-categories': require('./eslint-internal-rules/no-invalid-meta-docs-categories'),
           'require-eslint-community': require('./eslint-internal-rules/require-eslint-community')
         }
@@ -224,6 +225,7 @@ module.exports = [
         { pattern: 'https://eslint.vuejs.org/rules/{{name}}.html' }
       ],
       'internal/no-invalid-meta': 'error',
+      'internal/no-invalid-meta-default-options': 'error',
       'internal/no-invalid-meta-docs-categories': 'error'
     }
   },
@@ -232,6 +234,7 @@ module.exports = [
     rules: {
       'eslint-plugin/require-meta-docs-url': 'off',
       'internal/no-invalid-meta': 'error',
+      'internal/no-invalid-meta-default-options': 'error',
       'internal/no-invalid-meta-docs-categories': 'error'
     }
   },