Add a test to cover #6426.

tests/python/pants_test/pantsd/pantsd_integration_test_base.py

@@ -84,15 +84,15 @@ def pantsd_test_context(self, log_level='info', extra_config=None, expected_runs
           recursively_update(pantsd_config, extra_config)
         print('>>> config: \n{}\n'.format(pantsd_config))
         checker = PantsDaemonMonitor(pid_dir)
-        self.assert_success_runner(workdir, pantsd_config, ['kill-pantsd'])
+        self.assert_runner(workdir, pantsd_config, ['kill-pantsd'])
         try:
           yield workdir, pantsd_config, checker
         finally:
           banner('BEGIN pantsd.log')
           for line in read_pantsd_log(workdir):
             print(line)
           banner('END pantsd.log')
-          self.assert_success_runner(
+          self.assert_runner(
             workdir,
             pantsd_config,
             ['kill-pantsd'],
@@ -101,14 +101,20 @@ def pantsd_test_context(self, log_level='info', extra_config=None, expected_runs
           checker.assert_stopped()
 
   @contextmanager
-  def pantsd_successful_run_context(self, log_level='info', extra_config=None, extra_env=None):
+  def pantsd_successful_run_context(self, *args, **kwargs):
+    with self.pantsd_run_context(*args, success=True, **kwargs) as context:
+      yield context
+
+  @contextmanager
+  def pantsd_run_context(self, log_level='info', extra_config=None, extra_env=None, success=True):
     with self.pantsd_test_context(log_level, extra_config) as (workdir, pantsd_config, checker):
       yield (
         functools.partial(
-          self.assert_success_runner,
+          self.assert_runner,
           workdir,
           pantsd_config,
           extra_env=extra_env,
+          success=success,
         ),
         checker,
         workdir,
@@ -122,7 +128,7 @@ def _run_count(self, workdir):
     else:
       return 0
 
-  def assert_success_runner(self, workdir, config, cmd, extra_config={}, extra_env={}, expected_runs=1):
+  def assert_runner(self, workdir, config, cmd, extra_config={}, extra_env={}, expected_runs=1, success=True):
     combined_config = config.copy()
     recursively_update(combined_config, extra_config)
     print(bold(cyan('\nrunning: ./pants {} (config={}) (extra_env={})'
@@ -149,5 +155,8 @@ def assert_success_runner(self, workdir, config, cmd, extra_config={}, extra_env
           runs_created,
         )
     )
-    self.assert_success(run)
+    if success:
+      self.assert_success(run)
+    else:
+      self.assert_failure(run)
     return run

tests/python/pants_test/pantsd/test_pantsd_integration.py

@@ -370,6 +370,25 @@ def test_pantsd_invalidation_stale_sources(self):
     finally:
       rm_rf(test_path)
 
+  def test_pantsd_parse_exception_success(self):
+    # This test covers the case described in #6426, where a run that is failing fast due to an
+    # exception can race other completing work. We expect all runs to fail due to the error
+    # that has been introduced, but none of them should hang.
+    test_path = 'testprojects/3rdparty/this_is_definitely_not_a_valid_directory'
+    test_build_file = os.path.join(test_path, 'BUILD')
+    invalid_symbol = 'this_is_definitely_not_a_valid_symbol'
+
+    try:
+      safe_mkdir(test_path, clean=True)
+      safe_file_dump(test_build_file, "{}()".format(invalid_symbol), binary_mode=False)
+      for _ in range(3):
+        with self.pantsd_run_context(success=False) as (pantsd_run, checker, _, _):
+          result = pantsd_run(['list', 'testprojects::'])
+          checker.assert_started()
+          self.assertIn(invalid_symbol, result.stderr_data)
+    finally:
+      rm_rf(test_path)
+
   def test_pantsd_multiple_parallel_runs(self):
     with self.pantsd_test_context() as (workdir, config, checker):
       file_to_make = os.path.join(workdir, 'some_magic_file')