Use clang-tidy config file from repo instead of default (#29595)

Author: jmagman

tools/clang_tidy/lib/clang_tidy.dart

@@ -184,7 +184,7 @@ class ClangTidy {
  Future<_ComputeJobsResult> _computeJobs(
  List<Command> commands,
  io.Directory repoPath,
- String checks,
+ String? checks,
  ) async {
  bool sawMalformed = false;
  final List<WorkerJob> jobs = <WorkerJob>[];

tools/clang_tidy/lib/src/command.dart

@@ -126,8 +126,13 @@ class Command {
  }
 
  /// The job for the process runner for the lint needed for this command.
- WorkerJob createLintJob(String checks) {
- final List<String> args = <String>[filePath, checks, '--'];
+ WorkerJob createLintJob(String? checks) {
+ final List<String> args = <String>[
+ filePath,
+ if (checks != null)
+ checks,
+ '--',
+ ];
  args.addAll(tidyArgs.split(' '));
  return WorkerJob(
  <String>[tidyPath, ...args],

tools/clang_tidy/lib/src/options.dart

@@ -19,10 +19,8 @@ class Options {
  this.lintAll = false,
  this.errorMessage,
  StringSink? errSink,
- }) {
- checks = checksArg.isNotEmpty ? '--checks=$checksArg' : '--config=';
- _errSink = errSink ?? io.stderr;
- }
+ }) : checks = checksArg.isNotEmpty ? '--checks=$checksArg' : null,
+ _errSink = errSink ?? io.stderr;
 
  factory Options._error(
  String message, {
@@ -131,7 +129,7 @@ class Options {
  final String checksArg;
 
  /// Check arguments to plumb through to clang-tidy.
- late final String checks;
+ final String? checks;
 
  /// Whether all files should be linted.
  final bool lintAll;
@@ -140,7 +138,7 @@ class Options {
  /// contains the error message.
  final String? errorMessage;
 
- late final StringSink _errSink;
+ final StringSink _errSink;
 
  /// Print command usage with an additional message.
  void printUsage({String? message}) {

tools/clang_tidy/test/clang_tidy_test.dart

@@ -7,6 +7,7 @@ import 'dart:io' as io show Directory, File, Platform, stderr;
 import 'package:clang_tidy/clang_tidy.dart';
 import 'package:clang_tidy/src/command.dart';
 import 'package:litetest/litetest.dart';
+import 'package:process_runner/process_runner.dart';
 
 Future<int> main(List<String> args) async {
  if (args.length < 2) {
@@ -199,7 +200,16 @@ Future<int> main(List<String> args) async {
  );
 
  expect(commands, isNotEmpty);
- expect(commands.first.tidyPath, contains('clang/bin/clang-tidy'));
+ final Command command = commands.first;
+ expect(command.tidyPath, contains('clang/bin/clang-tidy'));
+ final WorkerJob job = command.createLintJob(null);
+ expect(job.command, <String>[
+ '../../buildtools/mac-x64/clang/bin/clang-tidy',
+ filePath,
+ '--',
+ '',
+ filePath,
+ ]);
  });
 
  test('Command getLintAction flags third_party files', () async {