Implement new rule: no-reaching-inside

Author: spalger

Diff for: docs/rules/no-reaching-inside.md

@@ -0,0 +1,64 @@
+# no-reaching-inside
+
+Use this rule to prevent importing the submodules of other modules.
+
+## Rule Details
+
+This rule has one option, `allow` which is an array of minimatch patterns to identify directories whose children can be imported explicitly.
+
+### Examples
+
+Given the following folder structure:
+
+```
+my-project
+├── actions
+│   └── getUser.js
+│   └── updateUser.js
+├── reducer
+│   └── index.js
+│   └── user.js
+├── redux
+│   └── index.js
+│   └── configureStore.js
+└── app
+│   └── index.js
+│   └── settings.js
+└── entry.js
+```
+
+And the .eslintrc file:
+```
+{
+  ...
+  "rules": {
+    "import/no-reaching-inside": [ "error", {
+      "allow": [ "**/actions", "source-map-support/*" ]
+    } ]
+  }
+}
+```
+
+The following patterns are considered problems:
+
+```js
+/**
+ *  in my-project/entry.jz
+ */
+
+import { settings } from './app/index'; // Reaching into "./app" is not allowed
+import userReducer from './reducer/user'; // Reaching into "./reducer" is not allowed
+import configureStore from './redux/configureStore'; // Reaching into "./redux" is not allowed
+```
+
+The following patterns are NOT considered problems:
+
+```js
+/**
+ *  in my-project/entry.jz
+ */
+
+import 'source-map-support/register';
+import { settings } from '../app';
+import getUser from '../actions/getUser';
+```

Diff for: package.json

@@ -79,6 +79,7 @@
     "lodash.endswith": "^4.0.1",
     "lodash.find": "^4.3.0",
     "lodash.findindex": "^4.3.0",
+    "minimatch": "^3.0.3",
     "object-assign": "^4.0.1",
     "pkg-dir": "^1.0.0",
     "pkg-up": "^1.0.0"

Diff for: 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-reaching-inside': require('./rules/no-reaching-inside'),
 
   'no-named-as-default': require('./rules/no-named-as-default'),
   'no-named-as-default-member': require('./rules/no-named-as-default-member'),

Diff for: src/rules/no-reaching-inside.js

@@ -0,0 +1,99 @@
+import path from 'path'
+import find from 'lodash.find'
+import minimatch from 'minimatch'
+
+import importType from '../core/importType'
+import isStaticRequire from '../core/staticRequire'
+
+module.exports = function noReachingInside(context) {
+  const options = context.options[0] || {}
+  const dirname = path.dirname(context.getFilename())
+  const allowRegexps = (options.allow || []).map(p => minimatch.makeRe(p))
+
+  // test if reaching into this directory is allowed by the
+  // config, path.sep is automatically added so that globs like
+  // "lodash/**" will match both "lodash" (which requires the trailing /) and "lodash/get"
+  function reachingAllowed(someDir) {
+    return !!find(allowRegexps, re => re.test(someDir) || re.test(someDir + path.sep))
+  }
+
+  function isRelativeStep (step) {
+    return step === '' || step === '.' || step === '..'
+  }
+
+  function report(reachedTo, node) {
+    context.report({
+      node,
+      message: `Reaching into "${reachedTo}" is not allowed.`,
+    })
+  }
+
+  function findNotAllowedReach(importPath, startingBase, join, ignoreStep) {
+    const steps = importPath.split('/').filter(Boolean)
+    let parentDir = startingBase
+    while (steps.length) {
+      const step = steps.shift()
+      parentDir = join(parentDir, step)
+
+      if (ignoreStep && ignoreStep(step)) continue
+
+      if (steps.length) {
+        if (!reachingAllowed(parentDir)) {
+          return parentDir
+        }
+      }
+    }
+  }
+
+  function checkRelativeImportForReaching(importPath, node) {
+    const reachedInto = findNotAllowedReach(importPath, dirname, path.resolve, isRelativeStep)
+    if (reachedInto) report(path.relative(dirname, reachedInto), node)
+  }
+
+  function checkAbsoluteImportForReaching(importPath, node) {
+    const reachedInto = findNotAllowedReach(importPath, '', path.join)
+    if (reachedInto) report(reachedInto, node)
+  }
+
+  function checkImportForReaching(importPath, node) {
+    switch (importType(importPath, context)) {
+      case 'parent':
+      case 'index':
+      case 'sibling':
+        return checkRelativeImportForReaching(importPath, node)
+
+      case 'external':
+      case 'internal':
+        return checkAbsoluteImportForReaching(importPath, node)
+      default:
+        return
+    }
+  }
+
+  return {
+    ImportDeclaration(node) {
+      checkImportForReaching(node.source.value, node.source)
+    },
+    CallExpression(node) {
+      if (isStaticRequire(node)) {
+        const [ firstArgument ] = node.arguments
+        checkImportForReaching(firstArgument.value, firstArgument)
+      }
+    },
+  }
+}
+
+module.exports.schema = [
+  {
+    type: 'object',
+    properties: {
+      allow: {
+        type: 'array',
+        items: {
+          type: 'string',
+        },
+      },
+    },
+    additionalProperties: false,
+  },
+]

Diff for: tests/files/reaching-inside/api/service/index.js

@@ -0,0 +1,94 @@
+import { RuleTester } from 'eslint'
+import rule from 'rules/no-reaching-inside'
+
+import { test, testFilePath } from '../utils'
+
+const ruleTester = new RuleTester()
+
+ruleTester.run('no-reaching-inside', rule, {
+  valid: [
+    test({
+      code: 'import a from "./plugin2"',
+      filename: testFilePath('./reaching-inside/plugins/plugin.js'),
+      options: [],
+    }),
+    test({
+      code: 'const a = require("./plugin2")',
+      filename: testFilePath('./reaching-inside/plugins/plugin.js'),
+    }),
+    test({
+      code: 'const a = require("./plugin2/")',
+      filename: testFilePath('./reaching-inside/plugins/plugin.js'),
+    }),
+    test({
+      code: 'const dynamic = "./plugin2/"; const a = require(dynamic)',
+      filename: testFilePath('./reaching-inside/plugins/plugin.js'),
+    }),
+    test({
+      code: 'import b from "./internal.js"',
+      filename: testFilePath('./reaching-inside/plugins/plugin2/index.js'),
+    }),
+    test({
+      code: 'import get from "lodash.get"',
+      filename: testFilePath('./reaching-inside/plugins/plugin2/index.js'),
+    }),
+    test({
+      code: 'import b from "../../api/service"',
+      filename: testFilePath('./reaching-inside/plugins/plugin2/internal.js'),
+      options: [ {
+        allow: [ '**/api' ],
+      } ],
+    }),
+    test({
+      code: 'import "jquery/dist/jquery"',
+      filename: testFilePath('./reaching-inside/plugins/plugin2/internal.js'),
+      options: [ {
+        allow: [ 'jquery/**' ],
+      } ],
+    }),
+    test({
+      code: 'import "/app/index.js"',
+      filename: testFilePath('./reaching-inside/plugins/plugin2/internal.js'),
+      options: [ {
+        allow: [ '/app' ],
+      } ],
+    }),
+  ],
+
+  invalid: [
+    test({
+      code: 'import b from "./plugin2/internal"',
+      filename: testFilePath('./reaching-inside/plugins/plugin.js'),
+      errors: [ {
+        message: 'Reaching into "plugin2" is not allowed.',
+        line: 1,
+        column: 15,
+      } ],
+    }),
+    test({
+      code: 'import a from "../api/service/index"',
+      filename: testFilePath('./reaching-inside/plugins/plugin.js'),
+      options: [ {
+        allow: [ '**/reaching-inside/*' ],
+      } ],
+      errors: [
+        {
+          message: 'Reaching into "../api/service" is not allowed.',
+          line: 1,
+          column: 15,
+        },
+      ],
+    }),
+    test({
+      code: 'import get from "lodash/get"',
+      filename: testFilePath('./reaching-inside/plugins/plugin.js'),
+      errors: [
+        {
+          message: 'Reaching into "lodash" is not allowed.',
+          line: 1,
+          column: 17,
+        },
+      ],
+    }),
+  ],
+})