Add rule 'no-self-import'

CHANGELOG.md

@@ -54,6 +54,7 @@ Yanked due to critical issue in eslint-module-utils with cache key resulting fro
 - [`no-anonymous-default-export`] rule: report anonymous default exports ([#712], thanks [@duncanbeevers]).
 - Add new value to [`order`]'s `newlines-between` option to allow newlines inside import groups ([#627], [#628], thanks [@giodamelio])
 - Add `count` option to the [`newline-after-import`] rule to allow configuration of number of newlines expected ([#742], thanks [@ntdb])
+- Add [`no-self-import`] rule: forbids a module from importing itself. ([#727], [#449], [#447], thanks [@giodamelio]).
 
 ### Changed
 - [`no-extraneous-dependencies`]: use `read-pkg-up` to simplify finding + loading `package.json` ([#680], thanks [@wtgtybhertgeghgtwtg])
@@ -433,6 +434,7 @@ for info on changes for earlier releases.
 [`no-anonymous-default-export`]: ./docs/rules/no-anonymous-default-export.md
 [`exports-last`]: ./docs/rules/exports-last.md
 [`group-exports`]: ./docs/rules/group-exports.md
+[`no-self-import`]: ./docs/rules/no-self-import.md
 
 [`memo-parser`]: ./memo-parser/README.md
 
@@ -444,6 +446,7 @@ for info on changes for earlier releases.
 [#744]: https://github.com/benmosher/eslint-plugin-import/pull/744
 [#742]: https://github.com/benmosher/eslint-plugin-import/pull/742
 [#737]: https://github.com/benmosher/eslint-plugin-import/pull/737
+[#727]: https://github.com/benmosher/eslint-plugin-import/pull/727
 [#721]: https://github.com/benmosher/eslint-plugin-import/pull/721
 [#712]: https://github.com/benmosher/eslint-plugin-import/pull/712
 [#696]: https://github.com/benmosher/eslint-plugin-import/pull/696
@@ -468,6 +471,7 @@ for info on changes for earlier releases.
 [#489]: https://github.com/benmosher/eslint-plugin-import/pull/489
 [#485]: https://github.com/benmosher/eslint-plugin-import/pull/485
 [#461]: https://github.com/benmosher/eslint-plugin-import/pull/461
+[#449]: https://github.com/benmosher/eslint-plugin-import/pull/449
 [#444]: https://github.com/benmosher/eslint-plugin-import/pull/444
 [#428]: https://github.com/benmosher/eslint-plugin-import/pull/428
 [#395]: https://github.com/benmosher/eslint-plugin-import/pull/395
@@ -533,6 +537,7 @@ for info on changes for earlier releases.
 [#456]: https://github.com/benmosher/eslint-plugin-import/issues/456
 [#453]: https://github.com/benmosher/eslint-plugin-import/issues/453
 [#452]: https://github.com/benmosher/eslint-plugin-import/issues/452
+[#447]: https://github.com/benmosher/eslint-plugin-import/issues/447
 [#441]: https://github.com/benmosher/eslint-plugin-import/issues/441
 [#423]: https://github.com/benmosher/eslint-plugin-import/issues/423
 [#416]: https://github.com/benmosher/eslint-plugin-import/issues/416

README.md

@@ -23,6 +23,7 @@ This plugin intends to support linting of ES2015+ (ES6+) import/export syntax, a
 * Forbid `require()` calls with expressions ([`no-dynamic-require`])
 * Prevent importing the submodules of other modules ([`no-internal-modules`])
 * Forbid Webpack loader syntax in imports ([`no-webpack-loader-syntax`])
+* Forbid a module from importing itself ([`no-self-import`])
 
 [`no-unresolved`]: ./docs/rules/no-unresolved.md
 [`named`]: ./docs/rules/named.md
@@ -33,6 +34,7 @@ This plugin intends to support linting of ES2015+ (ES6+) import/export syntax, a
 [`no-dynamic-require`]: ./docs/rules/no-dynamic-require.md
 [`no-internal-modules`]: ./docs/rules/no-internal-modules.md
 [`no-webpack-loader-syntax`]: ./docs/rules/no-webpack-loader-syntax.md
+[`no-self-import`]: ./docs/rules/no-self-import.md
 
 **Helpful warnings:**
 

docs/rules/no-self-import.md

@@ -0,0 +1,30 @@
+# Forbid a module from importing itself
+
+Forbid a module from importing itself. This can sometimes happen during refactoring.
+
+## Rule Details
+
+### Fail
+
+```js
+// foo.js
+import foo from './foo';
+
+const foo = require('./foo');
+```
+
+```js
+// index.js
+import index from '.';
+
+const index = require('.');
+```
+
+### Pass
+
+```js
+// foo.js
+import bar from './bar';
+
+const bar = require('./bar');
+```

src/index.js

@@ -11,6 +11,7 @@ export const rules = {
   'no-internal-modules': require('./rules/no-internal-modules'),
   'group-exports': require('./rules/group-exports'),
 
+  'no-self-import': require('./rules/no-self-import'),
   'no-named-default': require('./rules/no-named-default'),
   '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 +1,41 @@
+/**
+ * @fileOverview Forbids a module from importing itself
+ * @author Gio d'Amelio
+ */
+
+import resolve from 'eslint-module-utils/resolve'
+import isStaticRequire from '../core/staticRequire'
+
+function isImportingSelf(context, node, requireName) {
+  const filePath = context.getFilename()
+
+  // If the input is from stdin, this test can't fail
+  if (filePath !== '<text>' && filePath === resolve(requireName, context)) {
+    context.report({
+        node,
+        message: 'Module imports itself.',
+    })
+  }
+}
+
+module.exports = {
+  meta: {
+    doc: {
+      description: 'Forbid a module from importing itself',
+      recommended: true,
+    },
+    schema: [],
+  },
+  create: function (context) {
+    return {
+      ImportDeclaration(node) {
+        isImportingSelf(context, node, node.source.value)
+      },
+      CallExpression(node) {
+        if (isStaticRequire(node)) {
+          isImportingSelf(context, node, node.arguments[0].value)
+        }
+      },
+    }
+  },
+}

tests/files/index.js

@@ -0,0 +1 @@
+// Used in `no-self-import` tests

tests/files/no-self-import-folder/index.js

@@ -0,0 +1 @@
+// Used in `no-self-import` tests

tests/files/no-self-import.js

@@ -0,0 +1 @@
+// Used in `no-self-import` tests

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

@@ -0,0 +1,121 @@
+import { test, testFilePath } from '../utils'
+
+import { RuleTester } from 'eslint'
+
+const ruleTester = new RuleTester()
+    , rule = require('rules/no-self-import')
+
+const error = {
+  ruleId: 'no-self-import',
+  message: 'Module imports itself.',
+}
+
+ruleTester.run('no-self-import', rule, {
+  valid: [
+    test({
+      code: 'import _ from "lodash"',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'import find from "lodash.find"',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'import foo from "./foo"',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'import foo from "../foo"',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'import foo from "foo"',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'import foo from "./"',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'import foo from "@scope/foo"',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var _ = require("lodash")',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var find = require("lodash.find")',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var foo = require("./foo")',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var foo = require("../foo")',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var foo = require("foo")',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var foo = require("./")',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var foo = require("@scope/foo")',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var bar = require("./bar/index")',
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var bar = require("./bar")',
+      filename: testFilePath('./bar/index.js'),
+    }),
+    test({
+      code: 'var bar = require("./bar")',
+      filename: '<text>',
+    }),
+  ],
+  invalid: [
+    test({
+      code: 'import bar from "./no-self-import"',
+      errors: [error],
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var bar = require("./no-self-import")',
+      errors: [error],
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var bar = require("./no-self-import.js")',
+      errors: [error],
+      filename: testFilePath('./no-self-import.js'),
+    }),
+    test({
+      code: 'var bar = require(".")',
+      errors: [error],
+      filename: testFilePath('./index.js'),
+    }),
+    test({
+      code: 'var bar = require("./")',
+      errors: [error],
+      filename: testFilePath('./index.js'),
+    }),
+    test({
+      code: 'var bar = require("././././")',
+      errors: [error],
+      filename: testFilePath('./index.js'),
+    }),
+    test({
+      code: 'var bar = require("../no-self-import-folder")',
+      errors: [error],
+      filename: testFilePath('./no-self-import-folder/index.js'),
+    }),
+  ],
+})