cbuildbot: report cros/parent_buildbucket_id for COIL

BUG=chromium:1148834
TEST=./run_tests

Change-Id: I6e1b16f84c26e0d777c419c8dc76f913a9bab991
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2560220
Reviewed-by: Sean McAllister <smcallis@google.com>
Reviewed-by: LaMont Jones <lamontjones@chromium.org>
Commit-Queue: George Engelbrecht <engeg@google.com>
Tested-by: George Engelbrecht <engeg@google.com>
diff --git a/cbuildbot/stages/build_stages.py b/cbuildbot/stages/build_stages.py
index 69d2df0..8326405 100644
--- a/cbuildbot/stages/build_stages.py
+++ b/cbuildbot/stages/build_stages.py
@@ -223,7 +223,7 @@
       ]:
         builds = buildbucket_client.SearchAllBuilds(
             self._run.options.debug,
-            tags=['buildset:%s' % request_build.SlaveBuildSet(master_id)],
+            tags=['buildset:%s' % request_build.ChildBuildSet(master_id)],
             status=status)
 
         ids = buildbucket_lib.ExtractBuildIds(builds)
diff --git a/lib/request_build.py b/lib/request_build.py
index 7d59245..9e63fc8 100644
--- a/lib/request_build.py
+++ b/lib/request_build.py
@@ -33,19 +33,19 @@
     ('bucket', 'buildbucket_id', 'build_config', 'url', 'created_ts'))
 
 
-def SlaveBuildSet(master_buildbucket_id):
+def ChildBuildSet(parent_buildbucket_id):
   """Compute the buildset id for all slaves of a master builder.
 
   Args:
-    master_buildbucket_id: The buildbucket id of the master build.
+    parent_buildbucket_id: The buildbucket id of the master build.
 
   Returns:
     A string to use as a buildset for the slave builders, or None.
   """
-  if not master_buildbucket_id:
+  if not parent_buildbucket_id:
     return None
 
-  return 'cros/master_buildbucket_id/%s' % master_buildbucket_id
+  return 'cros/parent_buildbucket_id/%s' % parent_buildbucket_id
 
 class RequestBuild(object):
   """Request a builder via buildbucket."""
@@ -129,7 +129,7 @@
     """
     tags = {
         # buildset identifies a group of related builders.
-        'buildset': SlaveBuildSet(self.master_buildbucket_id),
+        'buildset': ChildBuildSet(self.master_buildbucket_id),
         'cbb_display_label': self.display_label,
         'cbb_branch': self.branch,
         'cbb_config': self.build_config,
diff --git a/lib/request_build_unittest.py b/lib/request_build_unittest.py
index 1048b41..dde021e 100644
--- a/lib/request_build_unittest.py
+++ b/lib/request_build_unittest.py
@@ -130,7 +130,7 @@
         'parameters_json': mock.ANY,
         'bucket': self.TEST_BUCKET,
         'tags': [
-            'buildset:cros/master_buildbucket_id/master_bb_id',
+            'buildset:cros/parent_buildbucket_id/master_bb_id',
             'cbb_branch:test-branch',
             'cbb_config:amd64-generic-paladin',
             'cbb_display_label:display',
@@ -149,7 +149,7 @@
         u'email_notify': [{u'email': u'explicit_email',
                            u'template': u'explicit_template'}],
         u'properties': {
-            u'buildset': u'cros/master_buildbucket_id/master_bb_id',
+            u'buildset': u'cros/parent_buildbucket_id/master_bb_id',
             u'cbb_branch': u'test-branch',
             u'cbb_config': u'amd64-generic-paladin',
             u'cbb_display_label': u'display',
@@ -302,7 +302,7 @@
         self.TEST_BUCKET,
         [
             'builder:luci_build',
-            'buildset:cros/master_buildbucket_id/master_bb_id',
+            'buildset:cros/parent_buildbucket_id/master_bb_id',
             'cbb_branch:test-branch',
             'cbb_display_label:display',
             'cbb_config:amd64-generic-paladin',
@@ -316,7 +316,7 @@
             u'email_notify': [{u'email': u'explicit_email',
                                u'template': u'explicit_template'}],
             u'properties': {
-                u'buildset': u'cros/master_buildbucket_id/master_bb_id',
+                u'buildset': u'cros/parent_buildbucket_id/master_bb_id',
                 u'cbb_branch': u'test-branch',
                 u'cbb_config': u'amd64-generic-paladin',
                 u'cbb_display_label': u'display',