feat: readonly properties for static class (ex: summary)

src/index.ts

@@ -28,6 +28,7 @@ import { getConnectionWithVersion } from './rules/getConnectionsWithVersion';
 import { noOclifFlagsCommandImport } from './rules/noOclifFlagsCommandImport';
 import { noBuiltinFlags } from './rules/migration/noBuiltinFlags';
 import { dashO } from './rules/dash-o';
+import { readOnlyProperties } from './rules/readOnlyProperties';
 
 const recommended = {
   plugins: ['sf-plugin'],
@@ -47,6 +48,7 @@ const recommended = {
     'sf-plugin/json-flag': 'error',
     'sf-plugin/run-matches-class-type': 'error',
     'sf-plugin/no-oclif-flags-command-import': 'error',
+    'sf-plugin/read-only-properties': 'warning',
   },
 };
 export = {
@@ -93,5 +95,6 @@ export = {
     'no-oclif-flags-command-import': noOclifFlagsCommandImport,
     'no-builtin-flags': noBuiltinFlags,
     'dash-o': dashO,
+    'read-only-properties': readOnlyProperties,
   },
 };

src/rules/readOnlyProperties.ts

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2020, salesforce.com, inc.
+ * All rights reserved.
+ * Licensed under the BSD 3-Clause license.
+ * For full license text, see LICENSE.txt file in the repo root or https://opensource.org/licenses/BSD-3-Clause
+ */
+import { AST_NODE_TYPES, ESLintUtils } from '@typescript-eslint/utils';
+import { extendsSfCommand, isInCommandDirectory } from '../shared/commands';
+
+const props = ['summary', 'description', 'examples', 'flags', 'requiresProject', 'hidden'];
+
+export const readOnlyProperties = ESLintUtils.RuleCreator.withoutDocs({
+  meta: {
+    docs: {
+      description: 'Class-level static properties, like flags or descriptions, should be marked read-only',
+      recommended: 'error',
+    },
+    messages: {
+      message: 'The {{prop}} property should be read-only',
+    },
+    type: 'problem',
+    fixable: 'code',
+    schema: [],
+  },
+  defaultOptions: [],
+  create(context) {
+    return isInCommandDirectory(context)
+      ? {
+          PropertyDefinition(node): void {
+            if (
+              !node.readonly &&
+              node.static &&
+              node.key.type === AST_NODE_TYPES.Identifier &&
+              props.includes(node.key.name) &&
+              node.parent.type === AST_NODE_TYPES.ClassBody &&
+              node.parent.parent.type === AST_NODE_TYPES.ClassDeclaration &&
+              extendsSfCommand(node.parent.parent)
+            ) {
+              context.report({
+                node,
+                messageId: 'message',
+                data: { prop: node.key.name },
+                fix: (fixer) => fixer.insertTextBefore(node.key, 'readonly '),
+              });
+            }
+          },
+        }
+      : {};
+  },
+});

test/rules/readOnlyProperties.test.ts

@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2020, salesforce.com, inc.
+ * All rights reserved.
+ * Licensed under the BSD 3-Clause license.
+ * For full license text, see LICENSE.txt file in the repo root or https://opensource.org/licenses/BSD-3-Clause
+ */
+import path from 'path';
+import { ESLintUtils } from '@typescript-eslint/utils';
+import { readOnlyProperties } from '../../src/rules/readOnlyProperties';
+
+const ruleTester = new ESLintUtils.RuleTester({
+  parser: '@typescript-eslint/parser',
+});
+
+ruleTester.run('readOnlyProperties', readOnlyProperties, {
+  valid: [
+    {
+      name: 'correct example for a command',
+      code: `
+export default class EnvCreateScratch extends SfCommand<ScratchCreateResponse> {
+  public static readonly summary = 'foo'
+  public static readonly examples = 'baz'
+}
+`,
+    },
+    {
+      name: 'not an sf command',
+      code: `
+export default class EnvCreateScratch extends somethingElse<ScratchCreateResponse> {
+  public static description = 'bar'
+}
+`,
+    },
+    {
+      name: 'not in the commands folder',
+      filename: path.normalize('foo.ts'),
+      code: `
+export default class EnvCreateScratch extends SfCommand<ScratchCreateResponse> {
+  public static description = 'bar'
+  public static summary = 'baz'
+}
+`,
+    },
+  ],
+  invalid: [
+    {
+      name: 'does not have readonly',
+      filename: path.normalize('src/commands/foo.ts'),
+      errors: [
+        {
+          messageId: 'message',
+          data: { prop: 'description' },
+        },
+        {
+          messageId: 'message',
+          data: { prop: 'summary' },
+        },
+      ],
+      code: `
+export default class EnvCreateScratch extends SfCommand<ScratchCreateResponse> {
+  public static description = 'bar'
+  public static summary = 'baz'
+}
+`,
+      output: `
+export default class EnvCreateScratch extends SfCommand<ScratchCreateResponse> {
+  public static readonly description = 'bar'
+  public static readonly summary = 'baz'
+}
+`,
+    },
+  ],
+});