Added no-self-import rule

New rule checks against importing from the current file. Ref #447

Author: Pavel Žák

src/index.js

@@ -8,6 +8,7 @@ export const rules = {
   'no-mutable-exports': require('./rules/no-mutable-exports'),
   'extensions': require('./rules/extensions'),
   'no-restricted-paths': require('./rules/no-restricted-paths'),
+  'no-self-import': require('./rules/no-self-import'),
 
   'no-named-as-default': require('./rules/no-named-as-default'),
   'no-named-as-default-member': require('./rules/no-named-as-default-member'),

src/rules/no-self-import.js

@@ -0,0 +1,17 @@
+var path = require('path')
+
+module.exports = function (context) {
+  function checkSelfImport(node) {
+    var fileName = path.basename(context.getFilename())
+    var fileNameNoExtension = path.basename(fileName, path.extname(fileName))
+    var badPaths = ['./' + fileName, './' + fileNameNoExtension]
+
+    if (~badPaths.indexOf(node.source.value)) {
+      context.report(node, 'Importing from the current file.')
+    }
+  }
+
+  return {
+    'ImportDeclaration': checkSelfImport.bind(null),
+  }
+}

tests/src/rules/no-self-import.js

@@ -0,0 +1,73 @@
+import { test, SYNTAX_CASES } from '../utils'
+import { RuleTester } from 'eslint'
+
+const ruleTester = new RuleTester()
+    , rule = require('rules/no-self-import')
+
+ruleTester.run('no-self-import', rule, {
+  valid: [
+    test({ filename: 'foo', code: 'import "./bar"' }),
+    test({ filename: 'foo', code: 'import "./bar.js"' }),
+    test({ filename: 'foo.js', code: 'import "./bar"' }),
+    test({ filename: 'foo.js', code: 'import "./bar.js"' }),
+    test({ filename: 'foo.jsx', code: 'import "./bar"' }),
+    test({ filename: 'foo.jsx', code: 'import "./bar.jsx"' }),
+    test({ filename: 'foo.jsx', code: 'import "./foo.js"' }),
+
+    // es7
+    test({ filename: 'foo.js', code: 'export bar, { foo } from "./bar";', parser: 'babel-eslint' }),
+    test({ filename: 'foo.js', code: 'export bar from "./bar";', parser: 'babel-eslint' }),
+
+    ...SYNTAX_CASES,
+  ],
+
+  invalid: [
+    test({
+      code: 'import "./foo";',
+      filename: 'foo.jsx',
+      errors: [
+        { message: 'Importing from the current file.', type: 'ImportDeclaration' },
+      ]
+    }),
+
+    test({
+      code: 'import "./foo.jsx";',
+      filename: 'foo.jsx',
+      errors: [
+        { message: 'Importing from the current file.', type: 'ImportDeclaration' },
+      ]
+    }),
+
+    test({
+      code: 'import foo from "./foo";',
+      filename: 'foo.jsx',
+      errors: [
+        { message: 'Importing from the current file.', type: 'ImportDeclaration' },
+      ]
+    }),
+
+    test({
+      code: 'import foo from "./foo.jsx";',
+      filename: 'foo.jsx',
+      errors: [
+        { message: 'Importing from the current file.', type: 'ImportDeclaration' },
+      ]
+    }),
+
+    test({
+      code: 'import { foo } from "./foo";',
+      filename: 'foo.jsx',
+      errors: [
+        { message: 'Importing from the current file.', type: 'ImportDeclaration' },
+      ]
+    }),
+
+    test({
+      code: 'import { foo } from "./foo.jsx";',
+      filename: 'foo.jsx',
+      errors: [
+        { message: 'Importing from the current file.', type: 'ImportDeclaration' },
+      ]
+    }),
+  ],
+})