fix(markdown): scope user rule overrides away from md files (#844)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antfu

README.md

@@ -519,14 +519,17 @@ export default antfu(
     },
   },
   {
-    // Without `files`, they are general rules for all files
+    // Without `files`, they are general rules for all files (Markdown excluded — see note below)
     rules: {
       'style/semi': ['error', 'never'],
     },
   }
 )
 ```
 
+> [!NOTE]
+> Rule overrides without an explicit `files` constraint are automatically excluded from Markdown files, via [`composer.setDefaultIgnores`](https://github.com/antfu/eslint-flat-config-utils#composersetdefaultignores). This prevents JS-only rules (e.g. `no-irregular-whitespace`, `perfectionist/sort-imports`) from crashing on `@eslint/markdown`'s `SourceCode`, which doesn't expose JS-specific methods like `getAllComments()`. If you want a rule to apply to Markdown, scope it explicitly with `files: ['**/*.md']`.
+
 We also provided the `overrides` options in each integration to make it easier:
 
 ```js

fixtures/eslint.config.ts

@@ -1,4 +1,4 @@
-import { antfu } from './src'
+import { antfu } from '../src'
 
 export default antfu(
   {

fixtures/output/issue-837/javascript.js

@@ -0,0 +1,72 @@
+// This file is generated by ChatGPT
+
+// eslint-disable-next-line no-console
+const log = console.log
+
+// Define a class using ES6 class syntax
+class Person {
+  constructor(name, age) {
+    this.name = name
+    this.age = age
+  }
+
+  // Define a method within the class
+  sayHello() {
+    log(`Hello, my name is ${this.name} and I am ${this.age} years old.`)
+  }
+}
+
+// Create an array of objects
+const people = [
+  new Person('Alice', 30),
+  new Person('Bob', 25),
+  new Person('Charlie', 35),
+]
+
+// Use the forEach method to iterate over the array
+people.forEach((person) => {
+  person.sayHello()
+})
+
+// Use a template literal to create a multiline string
+const multilineString = `
+  This is a multiline string
+  that spans multiple lines.
+`
+
+// Use destructuring assignment to extract values from an object
+const { name, age } = people[0]
+log(`First person in the array is ${name} and they are ${age} years old.`, multilineString)
+
+// Use the spread operator to create a new array
+const numbers = [1, 2, 3]
+const newNumbers = [...numbers, 4, 5]
+log(newNumbers)
+
+// Use a try-catch block for error handling
+try {
+  // Attempt to parse an invalid JSON string
+  JSON.parse('invalid JSON')
+}
+catch (error) {
+  console.error('Error parsing JSON:', error.message)
+}
+
+// Use a ternary conditional operator
+const isEven = num => num % 2 === 0
+const number = 7
+log(`${number} is ${isEven(number) ? 'even' : 'odd'}.`)
+
+// Use a callback function with setTimeout for asynchronous code
+setTimeout(() => {
+  log('This code runs after a delay of 2 seconds.')
+}, 2000)
+
+let a, b, c, d, foo
+
+if (a
+  || b
+  || c || d
+  || (d && b)) {
+  foo()
+}

fixtures/output/issue-837/jsx.jsx

@@ -0,0 +1,32 @@
+import React from 'react'
+
+const PATTERN = /\.\d+/g
+
+export function HelloWorld({
+  greeting = 'hello',
+  greeted = '"World"',
+  silent = false,
+  onMouseOver,
+}) {
+  const [num] = React.useState(() => Math
+    .floor (Math.random() * 1e+7)
+    .toString()
+    .replace(PATTERN, ''))
+
+  if (!greeting) {
+    return null
+  };
+
+  return (
+    <div className="HelloWorld" title={`You are visitor number ${num}`} onMouseOver={onMouseOver}>
+      <strong>{ greeting.slice(0, 1).toUpperCase() + greeting.slice(1).toLowerCase() }</strong>
+      {greeting.endsWith(',')
+        ? ' '
+        : <span style={{ color: '\grey' }}>", "</span> }
+      <em>
+        { greeted }
+      </em>
+      { (silent) ? '.' : '!'}
+    </div>
+  )
+}

fixtures/output/issue-837/markdown.md

@@ -0,0 +1,35 @@
+Header
+======
+
+_Look,_ code blocks are formatted *too!*
+
+```js
+// This should be handled by ESLint instead of Prettier
+function identity(x) {
+  if (foo) {
+    console.log('bar')
+  }
+}
+```
+
+```css
+/* This should be handled by Prettier */
+.foo { color:red;}
+```
+
+Pilot|Airport|Hours
+--|:--:|--:
+John Doe|SKG|1338
+Jane Roe|JFK|314
+
+- - - - - - - - - - - - - - -
+
++ List
+ + with a [link] (/to/somewhere)
++ and [another one]
+
+
+  [another one]:  http://example.com 'Example title'
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit.
+Curabitur consectetur maximus risus, sed maximus tellus tincidunt et.

fixtures/output/issue-837/toml.toml

@@ -0,0 +1,23 @@
+comma = [
+  1,
+  2,
+  3,
+]
+
+[foo]
+b = 1
+c = "hello"
+a = { answer = 42 }
+indent = [
+  1,
+  2
+]
+
+[a-table]
+apple.type = "fruit"
+apple.skin = "thin"
+apple.color = "red"
+
+orange.type = "fruit"
+orange.skin = "thick"
+orange.color = "orange"

pnpm-lock.yaml

@@ -75,7 +75,7 @@ catalogs:
     ansis: ^4.2.0
     cac: ^7.0.0
     eslint-config-flat-gitignore: ^2.3.0
-    eslint-flat-config-utils: ^3.1.0
+    eslint-flat-config-utils: ^3.2.0
     eslint-merge-processors: ^2.0.0
     eslint-plugin-antfu: ^3.2.2
     eslint-plugin-command: ^3.5.2

pnpm-workspace.yaml

@@ -53,22 +53,6 @@ export async function markdown(
         ...overridesMarkdown,
       },
     },
-    {
-      files,
-      name: 'antfu/markdown/disables/markdown',
-      rules: {
-        // Disable rules do not work with markdown sourcecode.
-        'command/command': 'off',
-        'no-irregular-whitespace': 'off',
-        'perfectionist/sort-exports': 'off',
-        'perfectionist/sort-imports': 'off',
-        'regexp/no-legacy-features': 'off',
-        'regexp/no-missing-g-flag': 'off',
-        'regexp/no-useless-dollar-replacements': 'off',
-        'regexp/no-useless-flag': 'off',
-        'style/indent': 'off',
-      },
-    },
     {
       files: [
         GLOB_MARKDOWN_CODE,

src/configs/markdown.ts

@@ -39,6 +39,7 @@ import {
 import { e18e } from './configs/e18e'
 import { formatters } from './configs/formatters'
 import { regexp } from './configs/regexp'
+import { GLOB_MARKDOWN } from './globs'
 import { interopDefault, isInEditorEnv } from './utils'
 
 const flatConfigProps = [
@@ -412,6 +413,14 @@ export function antfu(
       ...userConfigs as any,
     )
 
+  // Markdown uses the `markdown/gfm` language, whose `SourceCode` lacks JS-only
+  // methods like `getAllComments`. Without this, any rule override registered
+  // without a `files` constraint would apply globally and crash on `.md` files.
+  // See https://github.com/antfu/eslint-config/issues/837.
+  if (options.markdown ?? true) {
+    composer = composer.setDefaultIgnores(prev => [...prev, GLOB_MARKDOWN])
+  }
+
   if (autoRenamePlugins) {
     composer = composer
       .renamePlugins(defaultPluginRenaming)