Improve logging in the clang-tidy script

* Add timestamps to process pool status logs
* Log the remaining job names when only a few jobs are pending

See flutter/flutter#131689

Author: jason-simmons

DEPS

@@ -664,7 +664,7 @@ deps = {
   Var('github_git') + '/google/process.dart.git' + '@' + '0c9aeac86dcc4e3a6cf760b76fed507107e244d5', # 4.2.1
 
   'src/third_party/pkg/process_runner':
-  Var('github_git') + '/google/process_runner.git' + '@' + 'd632ea0bfd814d779fcc53a361ed33eaf3620a0b', # 4.0.1
+  Var('github_git') + '/google/process_runner.git' + '@' + 'f24c69efdcaf109168f23d381fa281453d2bc9b1', # 4.1.2
 
   'src/third_party/pkg/quiver':
   Var('github_git') + '/google/quiver-dart.git' + '@' + '90b92bee895e507d435012356a8b5c5f17eafa52', # 3.2.1

tools/clang_tidy/lib/clang_tidy.dart

@@ -89,8 +89,12 @@ class ClangTidy {
   final StringSink _outSink;
   final StringSink _errSink;
 
+  late final DateTime _startTime;
+
   /// Runs clang-tidy on the repo as specified by the [Options].
   Future<int> run() async {
+    _startTime = DateTime.now();
+
     if (options.help) {
       options.printUsage();
       return 0;
@@ -340,8 +344,20 @@ class ClangTidy {
 
   Future<int> _runJobs(List<WorkerJob> jobs) async {
     int result = 0;
-    final ProcessPool pool = ProcessPool();
+    final Set<String> pendingJobs = <String>{for (final WorkerJob job in jobs) job.name};
+
+    void reporter(int totalJobs, int completed, int inProgress, int pending, int failed) {
+      return _logWithTimestamp(ProcessPool.defaultReportToString(
+        totalJobs, completed, inProgress, pending, failed));
+    }
+
+    final ProcessPool pool = ProcessPool(printReport: reporter);
     await for (final WorkerJob job in pool.startWorkers(jobs)) {
+      pendingJobs.remove(job.name);
+      if (pendingJobs.isNotEmpty && pendingJobs.length <= 3) {
+        final List<String> sortedJobs = pendingJobs.toList()..sort();
+        _logWithTimestamp('Still running: $sortedJobs');
+      }
       if (job.result.exitCode == 0) {
         continue;
       }
@@ -358,4 +374,10 @@ class ClangTidy {
     }
     return result;
   }
+
+  void _logWithTimestamp(String message) {
+    final Duration elapsedTime = DateTime.now().difference(_startTime);
+    final String seconds = (elapsedTime.inSeconds % 60).toString().padLeft(2, '0');
+    _outSink.writeln('[${elapsedTime.inMinutes}:$seconds] $message');
+  }
 }