fix(require-meta-schema-description): handle non-iterable schema properties (#493)

Author: JoshuaKGoldberg

Diff for: lib/rules/require-meta-schema-description.js

@@ -87,9 +87,11 @@ module.exports = {
           case 'properties': {
             hadChildren = true;
 
-            for (const property of value.properties) {
-              if (property.value?.type === 'ObjectExpression') {
-                checkSchemaElement(property.value);
+            if (Array.isArray(value.properties)) {
+              for (const property of value.properties) {
+                if (property.value?.type === 'ObjectExpression') {
+                  checkSchemaElement(property.value);
+                }
               }
             }
 

Diff for: tests/lib/rules/require-meta-schema-description.js

@@ -145,6 +145,41 @@ module.exports = {
   create() {}
 };
 `,
+    `
+module.exports = {
+  meta: {
+    schema: [
+      {
+        type: 'object',
+        properties: null,
+        additionalProperties: false
+      }
+    ],
+  },
+  create() {}
+}
+  `,
+    `
+const DEFAULT_OPTIONS = Object.freeze({});
+
+module.exports = {
+  meta: {
+    schema: [
+      {
+        type: 'object',
+        properties: Object.fromEntries(
+          Object.keys(DEFAULT_OPTIONS).map((code) => [
+            code,
+            { type: 'boolean' }
+          ])
+        ),
+        additionalProperties: false
+      }
+    ],
+  },
+  create() {}
+}
+  `,
   ],
 
   invalid: [