Example of deadlock in test_runner.dart on process crash

tools/testing/dart/test_runner.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * Classes and methods for executing tests.
  *
  * This module includes:
  * - Managing parallel execution of tests, including timeout checks.
  * - Evaluating the output of each test as pass/fail/crash/timeout.
@@ skipping 653 matching lines @@
     return Strings.join(arguments, ' ') + '\n';
   }
 
   void _testCompleted() {
     var test = _currentTest;
     _currentTest = null;
     test.completed();
   }
 
   int _reportResult(String output) {
+    print ("_stdoutDrained: ${_currentTest.displayName}");
     _stdoutDrained = true;
     // output = '>>> TEST {PASS, FAIL, OK, CRASH, FAIL, TIMEOUT}'
     var outcome = output.split(" ")[2];
     var exitCode = 0;
     if (outcome == "CRASH") exitCode = -10;
     if (outcome == "FAIL" || outcome == "TIMEOUT") exitCode = 1;
     new TestOutput.fromCase(_currentTest, exitCode, outcome == "TIMEOUT", 
                    _testStdout, _testStderr, new Date.now().difference(_startTime));
     // Move on when both stdout and stderr has been drained.
     if (_stderrDrained) _testCompleted();
   }
 
   void _stderrDone() {
+    print ("_stdoutDrained: ${_currentTest.displayName}");
     _stderrDrained = true;
     // Move on when both stdout and stderr has been drained.
     if (_stdoutDrained) _testCompleted();
   }
 
   Function _readStdout(StringInputStream stream, List<String> buffer) {
     return () {
       var status;
       var line = stream.readLine();
       while (line != null) {
@@ skipping 28 matching lines @@
           buffer.add(line);
         }
         line = stream.readLine();
       }
     };
   }
 
   void _exitHandler(exitCode) {
     if (_timer != null) _timer.cancel();
     _process.close();
+    if (!(_stdoutDrained && stderrDrained)) {
+      print("*** POTENTIAL DEADLOCK on process restart");
+    }
     _startProcess(() {
       _reportResult(">>> TEST CRASH");
     });
   }
 
   void _timeoutHandler(ignore) {
     _process.onExit = (exitCode) {
       _process.close();
       _startProcess(() {
         _reportResult(">>> TEST TIMEOUT");
@@ skipping 381 matching lines @@
         // the developer doesn't waste his or her time trying to fix a bunch of
         // tests that appear to be broken but were actually just flakes that
         // didn't get retried because there had already been one failure.
         bool allowRetry = _MAX_FAILED_NO_RETRY > _progress.numFailedTests;
         new RunningProcess(test, allowRetry, this).start();
       }
       _numProcesses++;
     }
   }
 }