build: custom no catch block rule (#915)

* build: custom no catch block rule

* comment

* fix that

* fix that

* pr feedback

* Update packages/eslint-rules/src/rules/no_empty_catch.ts

Co-authored-by: Spencer Stolworthy <[email protected]>

---------

Co-authored-by: Spencer Stolworthy <[email protected]>

Author: Kamil Sobol

.changeset/lucky-pillows-approve.md

@@ -0,0 +1,5 @@
+---
+'@aws-amplify/platform-core': patch
+---
+
+fix empty catch block

.eslintrc.cjs

@@ -7,6 +7,7 @@ module.exports = {
   extends: [
     'eslint:recommended',
     'plugin:@typescript-eslint/recommended',
+    'plugin:amplify-backend-rules/recommended',
     'plugin:jsdoc/recommended-typescript-error',
     'plugin:promise/recommended',
     'prettier',
@@ -29,6 +30,7 @@ module.exports = {
   },
   plugins: [
     '@typescript-eslint',
+    'amplify-backend-rules',
     'unicorn',
     'jsdoc',
     'import',

package-lock.json

@@ -69,6 +69,7 @@
     "eslint": "^8.38.0",
     "eslint-config-prettier": "^8.8.0",
     "eslint-config-xo-typescript": "^0.57.0",
+    "eslint-plugin-amplify-backend-rules": "^0.0.1",
     "eslint-plugin-check-file": "^2.6.2",
     "eslint-plugin-import": "^2.27.5",
     "eslint-plugin-jsdoc": "^43.0.6",

package.json

@@ -0,0 +1,3 @@
+# ES lint rules
+
+This package contains custom linter rules used to validate amplify backend codebase.

packages/eslint-rules/README.md

@@ -0,0 +1,14 @@
+{
+  "name": "eslint-plugin-amplify-backend-rules",
+  "private": true,
+  "version": "0.0.1",
+  "type": "commonjs",
+  "main": "lib/index.js",
+  "dependencies": {
+    "@typescript-eslint/utils": "^6.18.1"
+  },
+  "devDependencies": {
+    "@typescript-eslint/rule-tester": "^6.18.1"
+  },
+  "license": "Apache-2.0"
+}

packages/eslint-rules/package.json

@@ -0,0 +1,14 @@
+import { rule } from './rules/no_empty_catch.js';
+
+export const rules: Record<string, unknown> = {
+  'no-empty-catch': rule,
+};
+
+export const configs = {
+  recommended: {
+    plugins: ['amplify-backend-rules'],
+    rules: {
+      'amplify-backend-rules/no-empty-catch': 'error',
+    },
+  },
+};

packages/eslint-rules/src/index.ts

@@ -0,0 +1,48 @@
+import * as nodeTest from 'node:test';
+import { RuleTester } from '@typescript-eslint/rule-tester';
+import { rule } from './no_empty_catch.js';
+
+RuleTester.afterAll = nodeTest.after;
+// See https://typescript-eslint.io/packages/rule-tester/#with-specific-frameworks
+// Node test runner methods return promises which are not relevant in the context of testing.
+// We do ignore them in other places with void keyword.
+// eslint-disable-next-line @typescript-eslint/no-misused-promises
+RuleTester.it = nodeTest.it;
+// eslint-disable-next-line @typescript-eslint/no-misused-promises
+RuleTester.describe = nodeTest.describe;
+
+const ruleTester = new RuleTester();
+
+ruleTester.run('no-empty-catch', rule, {
+  valid: [
+    'try {} catch (e) { console.log(e); }',
+    'try {} catch (e) { \n /* some comment*/ \n console.log(e); }',
+    'try {} catch (e) { \n // some comment \n console.log(e); }',
+  ],
+  invalid: [
+    {
+      code: 'try {} catch (e) { /* some comment */ }',
+      errors: [
+        {
+          messageId: 'noEmptyCatch',
+        },
+      ],
+    },
+    {
+      code: 'try {} catch (e) { \n // some comment \n }',
+      errors: [
+        {
+          messageId: 'noEmptyCatch',
+        },
+      ],
+    },
+    {
+      code: 'try {} catch (e) { }',
+      errors: [
+        {
+          messageId: 'noEmptyCatch',
+        },
+      ],
+    },
+  ],
+});

packages/eslint-rules/src/rules/no_empty_catch.test.ts

@@ -0,0 +1,36 @@
+import { ESLintUtils } from '@typescript-eslint/utils';
+
+/**
+ * This rule flags empty catch blocks. Even if they contain comments.
+ *
+ * This rule differs from built in https://github.com/eslint/eslint/blob/main/lib/rules/no-empty.js
+ * in such a way that it uses typescript-eslint and typescript AST
+ * which does not include comments as statements in catch clause body block.
+ */
+export const rule = ESLintUtils.RuleCreator.withoutDocs({
+  create(context) {
+    return {
+      // This naming comes from @typescript-eslint/utils types.
+      // eslint-disable-next-line @typescript-eslint/naming-convention
+      CatchClause(node) {
+        if (node.body.body.length === 0) {
+          context.report({
+            messageId: 'noEmptyCatch',
+            node,
+          });
+        }
+      },
+    };
+  },
+  meta: {
+    docs: {
+      description: 'Catch block should contain error-handling logic.',
+    },
+    messages: {
+      noEmptyCatch: 'Catch block must not be empty.',
+    },
+    type: 'problem',
+    schema: [],
+  },
+  defaultOptions: [],
+});

packages/eslint-rules/src/rules/no_empty_catch.ts

@@ -0,0 +1,5 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": { "rootDir": "src", "outDir": "lib", "allowJs": true },
+  "references": []
+}