Migrate build/commands to ESM

build/commands/PRESUBMIT.py

@@ -0,0 +1,58 @@
+# Copyright (c) 2026 The Brave Authors. All rights reserved.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at https://mozilla.org/MPL/2.0/.
+
+import os
+import re
+
+PRESUBMIT_VERSION = '2.0.0'
+
+
+def CheckImportSpecifierMatchesFile(input_api, output_api):
+    """Checks that relative import specifier matches the actual file on disk.
+
+    When running TypeScript natively via Node.js (no transpilation), imports
+    must use the real file extension. For example, if a file is named config.ts,
+    importing it as './config.js' is an error.
+    """
+
+    IMPORT_RE = re.compile(
+        r'''
+            (?:
+                \bfrom \s+      # static: import/export ... from
+              | \bimport \s* \( # dynamic: import(
+              | \bimport \s+    # side-effect: import './foo.js'
+            )
+            \s* ['"]
+            ( \.\.?/            # ./ or ../
+              [^'"]*            # path
+              \. [cm]?[jt]s     # file extension
+            )
+            ['"]
+        ''', re.VERBOSE)
+
+    files_to_check = (r'.+\.[cm]?[jt]s$', )
+    file_filter = lambda f: input_api.FilterSourceFile(
+        f, files_to_check=files_to_check)
+
+    items = []
+    for f in input_api.AffectedSourceFiles(file_filter):
+        file_dir = os.path.dirname(f.AbsoluteLocalPath())
+        for lineno, line in enumerate(f.NewContents(), 1):
+            for match in IMPORT_RE.finditer(line):
+                specifier = match.group(1)
+                resolved = os.path.normpath(os.path.join(file_dir, specifier))
+
+                if not os.path.isfile(resolved):
+                    items.append(f'{f.LocalPath()}:{lineno}: '
+                                 f'file not found: {specifier}')
+
+    if not items:
+        return []
+
+    return [
+        output_api.PresubmitError(
+            'Import path references a file that doesn\'t exist. '
+            'Check the file extension.', items)
+    ]

build/commands/PRESUBMIT_test.py

@@ -0,0 +1,211 @@
+# Copyright (c) 2026 The Brave Authors. All rights reserved.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at https://mozilla.org/MPL/2.0/.
+
+import os
+import tempfile
+import unittest
+
+import brave_chromium_utils
+
+# pylint: disable=import-error,no-member
+import PRESUBMIT
+
+with brave_chromium_utils.sys_path("//"):
+    from PRESUBMIT_test_mocks import MockAffectedFile
+    from PRESUBMIT_test_mocks import MockInputApi, MockOutputApi
+
+
+class ImportSpecifierTest(unittest.TestCase):
+
+    def setUp(self):
+        self._tmpdir = tempfile.mkdtemp()
+
+    def _run_check(self, files):
+        """Run the check with a files map.
+
+        Args:
+            files: dict mapping path -> lines list (affected file) or None
+                   (exists on disk only, not in the changelist).
+        """
+        input_api = MockInputApi()
+        input_api.files = []
+        for path, contents in files.items():
+            full = os.path.join(self._tmpdir, path)
+            os.makedirs(os.path.dirname(full), exist_ok=True)
+            if contents is not None:
+                affected_file = MockAffectedFile(path, contents)
+                affected_file.AbsoluteLocalPath = lambda p=full: p
+                input_api.files.append(affected_file)
+            else:
+                open(full, 'w').close()
+        return PRESUBMIT.CheckImportSpecifierMatchesFile(
+            input_api, MockOutputApi())
+
+    def testImportSpecifiers(self):
+        # files: path -> lines (affected source) or None (on-disk only).
+        cases = [
+            {
+                'name': 'correct .js extension',
+                'files': {
+                    'lib/build.js': ["import config from './config.js'"],
+                    'lib/config.js': None,
+                },
+                'expected_errors': 0,
+            },
+            {
+                'name': 'wrong extension: .js import but .ts file',
+                'files': {
+                    'lib/build.js': ["import config from './config.js'"],
+                    'lib/config.ts': None,
+                },
+                'expected_errors': 1,
+            },
+            {
+                'name': 'multiline import',
+                'files': {
+                    'lib/build.js': [
+                        "import {",
+                        "  getTestBinary,",
+                        "  getTestsToRun,",
+                        "} from './utils.js'",
+                    ],
+                    'lib/utils.ts': None,
+                },
+                'expected_errors': 1,
+            },
+            {
+                'name': 'dynamic import()',
+                'files': {
+                    'lib/build.js': [
+                        "const config = await import('./config.js')",
+                    ],
+                    'lib/config.ts': None,
+                },
+                'expected_errors': 1,
+            },
+            {
+                'name': 'side-effect import, wrong extension',
+                'files': {
+                    'lib/build.js': ["import './setup.js'"],
+                    'lib/setup.ts': None,
+                },
+                'expected_errors': 1,
+            },
+            {
+                'name': 'side-effect import, correct extension',
+                'files': {
+                    'lib/build.js': ["import './setup.js'"],
+                    'lib/setup.js': None,
+                },
+                'expected_errors': 0,
+            },
+            {
+                'name': 'export { } from',
+                'files': {
+                    'lib/index.js': ["export { foo } from './utils.js'"],
+                    'lib/utils.ts': None,
+                },
+                'expected_errors': 1,
+            },
+            {
+                'name': 'export * from, correct extension',
+                'files': {
+                    'lib/index.js': ["export * from './utils.js'"],
+                    'lib/utils.js': None,
+                },
+                'expected_errors': 0,
+            },
+            {
+                'name': 'correct .ts extension',
+                'files': {
+                    'lib/build.ts': ["import config from './config.ts'"],
+                    'lib/config.ts': None,
+                },
+                'expected_errors': 0,
+            },
+            {
+                'name': 'parent directory import',
+                'files': {
+                    'lib/build.js': ["import config from '../config.js'"],
+                    'config.ts': None,
+                },
+                'expected_errors': 1,
+            },
+            {
+                'name': 'non-relative imports are ignored',
+                'files': {
+                    'lib/build.js': [
+                        "import fs from 'fs-extra'",
+                        "import path from 'path'",
+                    ],
+                },
+                'expected_errors': 0,
+            },
+            {
+                'name': 'multiple errors in one file',
+                'files': {
+                    'lib/build.js': [
+                        "import config from './config.js'",
+                        "import util from './util.js'",
+                    ],
+                    'lib/config.ts': None,
+                    'lib/util.ts': None,
+                },
+                'expected_errors': 2,
+            },
+            {
+                'name': 'wrong .mjs extension',
+                'files': {
+                    'lib/build.mjs': ["import config from './config.mjs'"],
+                    'lib/config.mts': None,
+                },
+                'expected_errors': 1,
+            },
+            {
+                'name': 'require() is not matched',
+                'files': {
+                    'lib/build.cjs': [
+                        "const config = require('./config.cjs')",
+                    ],
+                    'lib/config.cts': None,
+                },
+                'expected_errors': 0,
+            },
+            {
+                'name': 'dotted filename, wrong extension',
+                'files': {
+                    'lib/build.js': [
+                        "import config from './config.base.js'",
+                    ],
+                    'lib/config.base.ts': None,
+                },
+                'expected_errors': 1,
+            },
+            {
+                'name': 'dotted filename, correct extension',
+                'files': {
+                    'lib/build.js': [
+                        "import config from './config.base.js'",
+                    ],
+                    'lib/config.base.js': None,
+                },
+                'expected_errors': 0,
+            },
+        ]
+
+        for case in cases:
+            with self.subTest(name=case['name']):
+                self._tmpdir = tempfile.mkdtemp()
+                results = self._run_check(case['files'])
+
+                items = [i for r in results for i in r.items]
+                self.assertEqual(
+                    case['expected_errors'], len(items),
+                    f"Expected {case['expected_errors']} errors, "
+                    f"got {len(items)}: {items}")
+
+
+if __name__ == '__main__':
+    unittest.main()

build/commands/lib/actionGuard.js

@@ -3,9 +3,9 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-const assert = require('assert')
-const fs = require('fs-extra')
-const path = require('path')
+import assert from 'assert'
+import fs from 'fs-extra'
+import path from 'path'
 
 // This function is used to get the call stack of the guarded operation. It is
 // stored in the guard file.
@@ -21,7 +21,7 @@ function getGuardCallStack() {
 
 // This class is used to ensure that a given action is successfully completed,
 // otherwise a rerun might be required.
-class ActionGuard {
+export default class ActionGuard {
   // Path to the guard file.
   #guardFilePath
   // Cleanup closure to perform a cleanup (optional) before running the action.
@@ -86,5 +86,3 @@ class ActionGuard {
     }
   }
 }
-
-module.exports = ActionGuard

build/commands/lib/actionGuard.test.js

@@ -3,9 +3,9 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-const fs = require('fs-extra')
-const path = require('path')
-const ActionGuard = require('./actionGuard')
+import fs from 'fs-extra'
+import path from 'path'
+import ActionGuard from './actionGuard.js'
 
 describe('ActionGuard', () => {
   const guardFilePath = '/path/to/guard/file'

build/commands/lib/affectedTests.js

@@ -3,19 +3,21 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-const { promisify } = require('util')
-const { readFile, writeFile } = require('fs/promises')
-const exec = promisify(require('child_process').execFile)
-const path = require('path')
-const config = require('./config')
-const { unlink } = require('fs-extra')
-const { randomUUID } = require('crypto')
-const {
+import { promisify } from 'node:util'
+import { readFile, writeFile } from 'fs/promises'
+import child_process from 'node:child_process'
+import path from 'path'
+import config from './config.js'
+import fs from 'fs-extra'
+import { randomUUID } from 'crypto'
+import { tmpdir } from 'os'
+import {
   getApplicableFilters,
   getTestsToRun,
   gnTargetToExecutableName,
-} = require('./testUtils')
-const { tmpdir } = require('os')
+} from './testUtils.js'
+
+const exec = promisify(child_process.execFile)
 
 const getTestTargets = (outDir, filters = ['//*']) => {
   const { env, shell } = config.defaultOptions
@@ -113,7 +115,7 @@ async function analyzeAffectedTests(
 
   const output = await readFile(analyzeOutJson, 'utf-8').then(JSON.parse)
 
-  await Promise.all([unlink(analyzeJson), unlink(analyzeOutJson)])
+  await Promise.all([fs.unlink(analyzeJson), fs.unlink(analyzeOutJson)])
 
   return {
     outDir,
@@ -167,7 +169,4 @@ async function getAffectedTests(args = {}) {
   return [...new Set([...affectedTests, ...testAffectedDueModifiedFilterFiles])]
 }
 
-module.exports = {
-  analyzeAffectedTests,
-  getAffectedTests,
-}
+export { analyzeAffectedTests, getAffectedTests }

build/commands/lib/applyPatches.js

@@ -3,8 +3,8 @@
 // License, v. 2.0. If a copy of the MPL was not distributed with this file,
 // You can obtain one at https://mozilla.org/MPL/2.0/.
 
-const config = require('../lib/config')
-const util = require('../lib/util')
+import config from './config.js'
+import util from './util.js'
 
 const applyPatches = (
   buildConfig = config.defaultBuildConfig,
@@ -22,4 +22,4 @@ const applyPatches = (
   })
 }
 
-module.exports = applyPatches
+export default applyPatches