refactor(core): Add lint rule no-internal-package-import (#18724)

packages/@n8n/eslint-config/src/configs/frontend.ts

@@ -38,6 +38,9 @@ export const frontendConfig = tseslint.config(
 		rules: {
 			'import-x/no-extraneous-dependencies': 'warn',
 			'vue/one-component-per-file': 'off',
+
+			// TODO: remove these
+			'n8n-local-rules/no-internal-package-import': 'warn',
 		},
 	},
 	{
@@ -98,6 +101,7 @@ export const frontendConfig = tseslint.config(
 			'vue/no-side-effects-in-computed-properties': 'warn',
 			'vue/no-v-text-v-html-on-component': 'warn',
 			'vue/return-in-computed-property': 'warn',
+			'n8n-local-rules/no-internal-package-import': 'warn',
 		},
 	},
 	eslintConfigPrettier,

packages/@n8n/eslint-config/src/plugin.ts

@@ -24,6 +24,7 @@ export const localRulesPlugin = {
 				'n8n-local-rules/no-interpolation-in-regular-string': 'error',
 				'n8n-local-rules/no-unused-param-in-catch-clause': 'error',
 				'n8n-local-rules/no-useless-catch-throw': 'error',
+				'n8n-local-rules/no-internal-package-import': 'error',
 			},
 		},
 	},

packages/@n8n/eslint-config/src/rules/index.ts

@@ -14,6 +14,7 @@ import { NoTopLevelRelativeImportsInBackendModuleRule } from './no-top-level-rel
 import { NoConstructorInBackendModuleRule } from './no-constructor-in-backend-module.js';
 import type { AnyRuleModule } from '@typescript-eslint/utils/ts-eslint';
 import { NoArgumentSpreadRule } from './no-argument-spread.js';
+import { NoInternalPackageImportRule } from './no-internal-package-import.js';
 
 export const rules = {
 	'no-uncaught-json-parse': NoUncaughtJsonParseRule,
@@ -31,4 +32,5 @@ export const rules = {
 	'no-top-level-relative-imports-in-backend-module': NoTopLevelRelativeImportsInBackendModuleRule,
 	'no-constructor-in-backend-module': NoConstructorInBackendModuleRule,
 	'no-argument-spread': NoArgumentSpreadRule,
+	'no-internal-package-import': NoInternalPackageImportRule,
 } satisfies Record<string, AnyRuleModule>;

packages/@n8n/eslint-config/src/rules/no-internal-package-import.test.ts

@@ -0,0 +1,30 @@
+import { RuleTester } from '@typescript-eslint/rule-tester';
+import { NoInternalPackageImportRule } from './no-internal-package-import.js';
+
+const ruleTester = new RuleTester();
+
+ruleTester.run('no-internal-package-import', NoInternalPackageImportRule, {
+	valid: [
+		{ code: 'import { SomeDto } from "@n8n/api-types"' },
+		{ code: 'import { Logger } from "@n8n/backend-common"' },
+		{ code: 'import { NodeHelpers } from "@n8n/workflow"' },
+		{ code: 'import lodash from "lodash"' },
+		{ code: 'import { helper } from "./local-file"' },
+		{ code: 'import { utils } from "../utils"' },
+		{ code: 'import express from "express"' },
+		{ code: 'import { something } from "@other-org/package/src/file"' },
+	],
+
+	invalid: [
+		{
+			code: 'import { UpdateDataStoreDto } from "@n8n/api-types/src/dto/data-store/update-data-store.dto"',
+			output: 'import { UpdateDataStoreDto } from "@n8n/api-types"',
+			errors: [{ messageId: 'noInternalPackageImport' }],
+		},
+		{
+			code: 'import { helper } from "@n8n/backend-common/src/utils/helper"',
+			output: 'import { helper } from "@n8n/backend-common"',
+			errors: [{ messageId: 'noInternalPackageImport' }],
+		},
+	],
+});

packages/@n8n/eslint-config/src/rules/no-internal-package-import.ts

@@ -0,0 +1,39 @@
+import { ESLintUtils } from '@typescript-eslint/utils';
+
+export const NoInternalPackageImportRule = ESLintUtils.RuleCreator.withoutDocs({
+	meta: {
+		type: 'problem',
+		docs: {
+			description: 'Disallow imports from internal package paths (e.g. `@n8n/pkg/src/...`).',
+		},
+		messages: {
+			noInternalPackageImport:
+				'Import from "{{ packageRoot }}", not from the internal `/src/` path.',
+		},
+		fixable: 'code',
+		schema: [],
+	},
+	defaultOptions: [],
+	create(context) {
+		const INTERNAL_IMPORT_REGEX = /^(?<packageRoot>@n8n\/[^/]+)\/src\//;
+
+		return {
+			ImportDeclaration(node) {
+				if (typeof node.source.type !== 'string') return;
+
+				const match = node.source.value.match(INTERNAL_IMPORT_REGEX);
+
+				if (!match?.groups) return;
+
+				const { packageRoot } = match.groups;
+
+				context.report({
+					node: node.source,
+					messageId: 'noInternalPackageImport',
+					fix: (fixer) => fixer.replaceText(node.source, `"${packageRoot}"`),
+					data: { packageRoot },
+				});
+			},
+		};
+	},
+});