[devil] Work around occasionally fatal `adb forward --list` bug.

devil/devil/android/sdk/adb_wrapper.py

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """This module wraps Android's adb tool.
 
 This is a thin wrapper around the adb interface. Any additional complexity
 should be delegated to a higher level (ex. DeviceUtils).
 """
 
@@ skipping 619 matching lines @@
     """
     self._RunDeviceAdbCmd(['forward', '--remove', str(local)], timeout,
                           retries)
 
   def ForwardList(self, timeout=DEFAULT_TIMEOUT, retries=DEFAULT_RETRIES):
     """List all currently forwarded socket connections.
 
     Args:
       timeout: (optional) Timeout per try in seconds.
       retries: (optional) Number of retries to attempt.
+    Returns:
+      The output of adb forward --list as a string.
     """
+    if (distutils.version.LooseVersion(self.Version()) >=
+        distutils.version.LooseVersion('1.0.36')):
+      # Starting in 1.0.36, this can occasionally fail with a protocol fault.
+      # As this interrupts all connections with all devices, we instead just
+      # return an empty list. This may give clients an inaccurate result, but
+      # that's usually better than crashing the adb server.
+
+      # TODO(jbudorick): Determine an appropriate upper version bound for this
+      # once b/31811775 is fixed.

[nednguyen, 2016/10/24 12:05:50]

Should we remove the bug reference since this is internal?

[jbudorick, 2016/10/24 13:46:16]

I'd definitely like to leave it here. It's certainly not our first b/ link:
https://codesearch.chromium.org/search/?q=%5C+b%5C/%5Cd%2B&sq=package:chromiu...

+      return ''
+
     return self._RunDeviceAdbCmd(['forward', '--list'], timeout, retries)
 
   def JDWP(self, timeout=DEFAULT_TIMEOUT, retries=DEFAULT_RETRIES):
     """List of PIDs of processes hosting a JDWP transport.
 
     Args:
       timeout: (optional) Timeout per try in seconds.
       retries: (optional) Number of retries to attempt.
 
     Returns:
@@ skipping 236 matching lines @@
   @property
   def is_emulator(self):
     return _EMULATOR_RE.match(self._device_serial)
 
   @property
   def is_ready(self):
     try:
       return self.GetState() == _READY_STATE
     except device_errors.CommandFailedError:
       return False