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Move error-subclass-name lint rule to GitHub
Summary: Ports an internal ESLint rule used at Facebook, `error-subclass-name`, to cover the React Native codebase. This rule enforces that error classes ( = those with PascalCase names ending with `Error`) only extend other error classes, and that regular functions don't have names that could be mistaken for those of error classes.

Reviewed By: rubennorte

Differential Revision: D17829298

fbshipit-source-id: 834e457343034a0897ab394b6a2d941789953d2e
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motiz88 authored and facebook-github-bot committed Oct 9, 2019
1 parent 1dc03f4 commit 6611c4b8f42520add983cc48fe4e14f7a02cc7cf
Showing 9 changed files with 228 additions and 5 deletions.
@@ -11,7 +11,8 @@
"Libraries/**/*.js",
],
rules: {
'@react-native-community/no-haste-imports': 2
'@react-native-community/no-haste-imports': 2,
'@react-native-community/error-subclass-name': 2,
}
},
{
@@ -119,7 +119,7 @@
"devDependencies": {
"@babel/core": "^7.0.0",
"@babel/generator": "^7.0.0",
"@react-native-community/eslint-plugin": "1.0.0",
"@react-native-community/eslint-plugin": "file:packages/eslint-plugin-react-native-community",
"@reactions/component": "^2.0.2",
"async": "^2.4.0",
"babel-eslint": "10.0.1",
@@ -0,0 +1,23 @@
load("@fbsource//tools/build_defs/third_party:yarn_defs.bzl", "yarn_workspace")

yarn_workspace(
name = "yarn-workspace",
srcs = glob(
["**/*.js"],
exclude = [
"**/__fixtures__/**",
"**/__flowtests__/**",
"**/__mocks__/**",
"**/__server_snapshot_tests__/**",
"**/__tests__/**",
"**/node_modules/**",
"**/node_modules/.bin/**",
"**/.*",
"**/.*/**",
"**/.*/.*",
"**/*.xcodeproj/**",
"**/*.xcworkspace/**",
],
),
visibility = ["PUBLIC"],
)
@@ -19,3 +19,15 @@ Add to your eslint config (`.eslintrc`, or `eslintConfig` field in `package.json
"plugins": ["@react-native-community"]
}
```

## Rules

### `error-subclass-name`

**NOTE:** This rule is primarily used for developing React Native itself and is not generally applicable to other projects.

Enforces that error classes ( = classes with PascalCase names ending with `Error`) only extend other error classes, and that regular functions don't have names that could be mistaken for those of error classes.

### `no-haste-imports`

Disallows Haste module names in `import` statements and `require()` calls.
@@ -0,0 +1,100 @@
/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @emails oncall+react_native
* @format
*/

'use strict';

const ESLintTester = require('./eslint-tester.js');

const rule = require('../error-subclass-name.js');

const eslintTester = new ESLintTester();

const INVALID_SUPERCLASS_MESSAGE =
"'SomethingEndingWithError' must extend an error class (like 'Error') because its name is in PascalCase and ends with 'Error'.";
const INVALID_OWN_NAME_MESSAGE =
"'Foo' may not be the name of an error class. It should be in PascalCase and end with 'Error'.";
const MISSING_OWN_NAME_MESSAGE =
"An error class should have a PascalCase name ending with 'Error'.";
const INVALID_FUNCTION_NAME_MESSAGE =
"'SomethingEndingWithError' is a reserved name. PascalCase names ending with 'Error' are reserved for error classes and may not be used for regular functions. Either rename this function or convert it to a class that extends 'Error'.";

eslintTester.run('../error-subclass-name', rule, {
valid: [
'class FooError extends Error {}',
'(class FooError extends Error {})',
'class FooError extends SomethingEndingWithError {}',
'(class FooError extends SomethingEndingWithError {})',
'function makeError() {}',
'(function () {})',

// The following cases are currently allowed but could be disallowed in the
// future. This is technically an escape hatch.
'class Foo extends SomeLibrary.FooError {}',
'(class extends SomeLibrary.FooError {})',
],
invalid: [
{
code: 'class SomethingEndingWithError {}',
errors: [{message: INVALID_SUPERCLASS_MESSAGE}],
},
{
code: '(class SomethingEndingWithError {})',
errors: [{message: INVALID_SUPERCLASS_MESSAGE}],
},
{
code: 'class Foo extends Error {}',
errors: [{message: INVALID_OWN_NAME_MESSAGE}],
},
{
code: '(class Foo extends Error {})',
errors: [{message: INVALID_OWN_NAME_MESSAGE}],
},
{
code: 'class Foo extends SomethingEndingWithError {}',
errors: [{message: INVALID_OWN_NAME_MESSAGE}],
},
{
code: '(class Foo extends SomethingEndingWithError {})',
errors: [{message: INVALID_OWN_NAME_MESSAGE}],
},
{
code: '(class extends Error {})',
errors: [{message: MISSING_OWN_NAME_MESSAGE}],
},
{
code: 'class SomethingEndingWithError extends C {}',
errors: [{message: INVALID_SUPERCLASS_MESSAGE}],
},
{
code: '(class SomethingEndingWithError extends C {})',
errors: [{message: INVALID_SUPERCLASS_MESSAGE}],
},
{
code: 'function SomethingEndingWithError() {}',
errors: [{message: INVALID_FUNCTION_NAME_MESSAGE}],
},
{
code: '(function SomethingEndingWithError() {})',
errors: [{message: INVALID_FUNCTION_NAME_MESSAGE}],
},

// The following cases are intentionally disallowed because the member
// expression `SomeLibrary.FooError` doesn't imply that the superclass is
// actually declared with the name `FooError`.
{
code: 'class SomethingEndingWithError extends SomeLibrary.FooError {}',
errors: [{message: INVALID_SUPERCLASS_MESSAGE}],
},
{
code: '(class SomethingEndingWithError extends SomeLibrary.FooError {})',
errors: [{message: INVALID_SUPERCLASS_MESSAGE}],
},
],
});
@@ -0,0 +1,22 @@
/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @format
*/

'use strict';

const ESLintTester = require('eslint').RuleTester;

ESLintTester.setDefaultConfig({
parser: 'babel-eslint',
parserOptions: {
ecmaVersion: 6,
sourceType: 'module',
},
});

module.exports = ESLintTester;
@@ -0,0 +1,66 @@
/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @format
*/

'use strict';

module.exports = function rule(context) {
function classVisitor(node) {
const {superClass, id} = node;
const nodeIsError = isErrorLikeId(id);
const superIsError = isErrorLikeId(superClass);
if (nodeIsError && !superIsError) {
const idName = getNameFromId(id);
context.report({
node: superClass || id,
message: `'${idName}' must extend an error class (like 'Error') because its name is in PascalCase and ends with 'Error'.`,
});
} else if (superIsError && !nodeIsError) {
const idName = getNameFromId(id);
context.report({
node: id || node,
message: idName
? `'${idName}' may not be the name of an error class. It should be in PascalCase and end with 'Error'.`
: "An error class should have a PascalCase name ending with 'Error'.",
});
}
}

function functionVisitor(node) {
const {id} = node;
const nodeIsError = isErrorLikeId(id);
if (nodeIsError) {
const idName = getNameFromId(id);
context.report({
node: id,
message: `'${idName}' is a reserved name. PascalCase names ending with 'Error' are reserved for error classes and may not be used for regular functions. Either rename this function or convert it to a class that extends 'Error'.`,
});
}
}

return {
ClassDeclaration: classVisitor,
ClassExpression: classVisitor,
FunctionExpression: functionVisitor,
FunctionDeclaration: functionVisitor,
};
};

// Checks whether `node` is an identifier (or similar name node) with a
// PascalCase name ending with 'Error'.
function isErrorLikeId(node) {
return (
node && node.type === 'Identifier' && /^([A-Z].*)?Error$/.test(node.name)
);
}

// If `node` is an identifier (or similar name node), returns its name as a
// string. Otherwise returns null.
function getNameFromId(node) {
return node ? node.name : null;
}
@@ -8,5 +8,6 @@
*/

exports.rules = {
'error-subclass-name': require('./error-subclass-name'),
'no-haste-imports': require('./no-haste-imports'),
};
@@ -1145,10 +1145,8 @@
shell-quote "1.6.1"
ws "^1.1.0"

"@react-native-community/eslint-plugin@1.0.0":
"@react-native-community/eslint-plugin@file:packages/eslint-plugin-react-native-community":
version "1.0.0"
resolved "https://registry.yarnpkg.com/@react-native-community/eslint-plugin/-/eslint-plugin-1.0.0.tgz#ae9a430f2c5795debca491f15a989fce86ea75a0"
integrity sha512-GLhSN8dRt4lpixPQh+8prSCy6PYk/MT/mvji/ojAd5yshowDo6HFsimCSTD/uWAdjpUq91XK9tVdTNWfGRlKQA==

"@reactions/component@^2.0.2":
version "2.0.2"

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