Reland "Allow multiple devices on bisects hosts "

scripts/slave/recipe_modules/auto_bisect/local_bisect.py

Index: scripts/slave/recipe_modules/auto_bisect/local_bisect.py
diff --git a/scripts/slave/recipe_modules/auto_bisect/local_bisect.py b/scripts/slave/recipe_modules/auto_bisect/local_bisect.py
index c5fb2cc8d93d65c0d111a9420be62228f68ddc0e..a89542cb4e57c27fc3684503f6d2e1b6e136d411 100644
--- a/scripts/slave/recipe_modules/auto_bisect/local_bisect.py
+++ b/scripts/slave/recipe_modules/auto_bisect/local_bisect.py
@@ -7,27 +7,53 @@ import collections
 import json
 
 
-def perform_bisect(api, **flags):  # pragma: no cover
-  bisect_config = api.m.properties.get('bisect_config')
-  assert isinstance(bisect_config, collections.Mapping)
-  bisector = api.create_bisector(bisect_config, **flags)
-  with api.m.step.nest('Gathering reference values'):
-    _gather_reference_range(api, bisector)
-  if (not bisector.failed and bisector.check_improvement_direction() and
-      bisector.check_initial_confidence()):
-    if bisector.check_reach_adjacent_revision(bisector.good_rev):
-      # Only show this step if bisect has reached adjacent revisions.
-      with api.m.step.nest(str('Check bisect finished on revision ' +
-                               bisector.good_rev.revision_string())):
-        if bisector.check_bisect_finished(bisector.good_rev):
-          bisector.bisect_over = True
-    if not bisector.bisect_over:
-      _bisect_main_loop(bisector)
+def perform_bisect(api, **flags):
+  if api.m.chromium.c.TARGET_PLATFORM != 'android':
+    _perform_single_bisect(api, **flags)
   else:
-    bisector.bisect_over = True
-  bisector.print_result_debug_info()
-  bisector.post_result(halt_on_failure=True)
+    # pick an available device if targe platform is android
+    if api.m.chromium.c.TARGET_PLATFORM == 'android':

[RobertoCN, 2016/07/15 19:59:47]

Is this check necessary again? look at the if in line 11.

[Ziqi Xiong, 2016/07/15 20:19:07]

Done.

+      connected_devices = _get_connected_devices(api)
+      if not connected_devices:
+        raise api.m.step.StepFailure('No Android test devices are available')
+      for device in connected_devices:
+        api.m.bisect_tester.device_to_test = device
+        try:
+          _perform_single_bisect(api, **flags)
+        except api.m.step.StepFailure:
+          # Redo the bisect job if target platform is android and bisect failed
+          # because the test device disconnected
+          connected_devices = _get_connected_devices(api)

[jbudorick, 2016/07/15 19:20:16]

This should no longer be here, right?

[Ziqi Xiong, 2016/07/15 19:23:58]

I think it should. The bisect should be redone
when  there is a step failure caused by tested
device disconnection. To see if the tested device
is disconnected, we need to do device_status again and
see if the tested device is missing from the list.

[jbudorick, 2016/07/15 19:31:23]

Oh, I see what you mean.

[RobertoCN, 2016/07/15 19:59:47]

Is there a way to check that one particular device is disconnected? It might
look a little cleaner.

Also, if running _get_connected_devices is necessary, store the result in other
variable, modifying the list you are iterating on may act strangely, and be hard
to debug.

[jbudorick, 2016/07/15 20:01:37]

I tried this out locally (on sample code) and I don't think it affects the
iteration.

That said, I do agree that it makes things more confusing, so +1

[Ziqi Xiong, 2016/07/15 20:19:07]

Done.

+          if api.m.bisect_tester.device_to_test not in connected_devices:
+            continue
+          else:
+            raise
+
+def _perform_single_bisect(api, **flags):
+      bisect_config = api.m.properties.get('bisect_config')
+      assert isinstance(bisect_config, collections.Mapping)
+      bisector = api.create_bisector(bisect_config, **flags)
+      with api.m.step.nest('Gathering reference values'):
+        _gather_reference_range(api, bisector)
+      if (not bisector.failed and bisector.check_improvement_direction() and
+          bisector.check_initial_confidence()):
+        if bisector.check_reach_adjacent_revision(
+            bisector.good_rev): # pragma: no cover
+          # Only show this step if bisect has reached adjacent revisions.
+          with api.m.step.nest(str('Check bisect finished on revision ' +
+                                   bisector.good_rev.revision_string())):
+            if bisector.check_bisect_finished(bisector.good_rev):
+              bisector.bisect_over = True
+        if not bisector.bisect_over:
+          _bisect_main_loop(bisector)
+      else:
+        bisector.bisect_over = True
+      bisector.print_result_debug_info()
+      bisector.post_result(halt_on_failure=True)
 
+def _get_connected_devices(api):
+  api.m.chromium_android.device_status()
+  return api.m.chromium_android.devices
 
 def _gather_reference_range(api, bisector):  # pragma: no cover
   bisector.good_rev.start_job()