Bug 93369 – [nrwt] fatal error during pixel tests: "ServerProcess.read() called with a non-positive size: 0"

• Status: NEW
• Component: Tools / Tests

[Balazs Kelemen]

I regularly hit this issue when running pixel tests on Qt-Linux. I guess it has some connection that we fail a lot tests but clearly this is a bug of nrwt.

Here is the error:
ValueError raised: ServerProcess.read() called with a non-positive size: 0 
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/run_webkit_tests.py", line 110, in run
      unexpected_result_count = manager.run(args)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/manager.py", line 411, in run
      self._run_tests(self._test_names, result_summary, int(self._options.child_processes))
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/manager.py", line 464, in _run_tests
      return self._runner.run_tests(test_inputs, self._expectations, result_summary, num_workers, needs_http, needs_websockets, self._retrying)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 140, in run_tests
      pool.run(('test_list', shard.name, shard.test_inputs) for shard in all_shards)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/common/message_pool.py", line 97, in run
      self.wait()
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/common/message_pool.py", line 127, in wait
      self._workers[0].run()
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/common/message_pool.py", line 267, in run
      self._raise(sys.exc_info())
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/common/message_pool.py", line 255, in run
      worker.handle(message.name, message.src, *message.args)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 304, in handle
      self._run_test(test_input)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 323, in _run_test
      result = self._run_test_with_timeout(test_input, test_timeout_sec)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 365, in _run_test_with_timeout
      return self._run_test_in_this_thread(test_input)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 450, in _run_test_in_this_thread
      return self._run_single_test(self._driver, test_input)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/layout_test_runner.py", line 454, in _run_single_test
      test_input, driver, self._name)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/single_test_runner.py", line 46, in run_single_test
      return runner.run()
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/single_test_runner.py", line 102, in run
      return self._run_compare_test()
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/controllers/single_test_runner.py", line 105, in _run_compare_test
      driver_output = self._driver.run_test(self._driver_input())
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/port/driver.py", line 492, in run_test
      return self._running_drivers[cmd_line_key].run_test(driver_input)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/port/driver.py", line 159, in run_test
      image, actual_image_hash = self._read_optional_image_block(deadline)  # The second (optional) block is image data.
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/port/driver.py", line 357, in _read_optional_image_block
      block = self._read_block(deadline, wait_for_stderr_eof=True)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/port/driver.py", line 421, in _read_block
      block.content = self._server_process.read_stdout(deadline, block._content_length)
    File "/home/balazs/WebKitGit/Tools/Scripts/webkitpy/layout_tests/port/server_process.py", line 186, in read_stdout
      raise ValueError('ServerProcess.read() called with a non-positive size: %d ' % size)