git cl try: load trybot list from cq.cfg by default.

git_cl.py

Index: git_cl.py
diff --git a/git_cl.py b/git_cl.py
index 49bed386baa821cfedf4370030bc9cb1b6afb452..e99509f1954776fc31fdf2996b0d18b7a9b234eb 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -42,6 +42,7 @@ import auth
 from luci_hacks import trigger_luci_job as luci_trigger
 import breakpad  # pylint: disable=W0611
 import clang_format
+import commit_queue

[Sergiy Byelozyorov, 2016/01/13 14:53:18]

not sure it's a good idea. this file is designed to be an executable, not a
module. perhaps it's better to move get_master_builder_map somewhere else, like
project_utils.py

[tandrii(chromium), 2016/01/13 15:16:36]

well, same thing with clang_format, which is also executable. So, long as
commit_queue doesn't have a weird mutable state, it's OK.

 import dart_format
 import fix_encoding
 import gclient_utils
@@ -3205,6 +3206,24 @@ def CMDtry(parser, args):
           None,
           options.verbose,
           sys.stdout)
+
+      if not options.bot:
+        # Get try masters from cq.cfg if any.
+        # TODO(tandrii): some (but very few) projects store cq.cfg in different
+        # location.
+        cq_cfg = os.path.join(change.RepositoryRoot(),
+                              'infra', 'config', 'cq.cfg')

[smut, 2016/01/25 21:16:38]

You can't hard code this path. Downstream iOS's cq.cfg is located at
ios_internal/infra/cq.cfg. With this change +
https://codereview.chromium.org/1620343003, our "git cl try" doesn't fetch try
bots from the right place at all anymore.

[tandrii(chromium), 2016/01/26 11:41:33]

what do you mean I can't? I sure can and just did :)
kidding aside, I was aware of other projects, but they are a minority. For most
projects, particularly news ones, this CL is a great default behavior which does
not require action from project owners.

I don't have a solution for other projects with non-standard infra config
location. Maybe going to luci-config and loading the CQ config from there? I do
accept patches though :)

+        if os.path.exists(cq_cfg):
+          masters = {}
+          cq_masters = commit_queue.get_master_builder_map(cq_cfg)
+          for master, builders in cq_masters.iteritems():
+            for builder in builders:
+              # Skip presubmit builders, because these will fail without LGTM.
+              if 'presubmit' not in builder.lower():
+                masters.setdefault(master, {})[builder] = ['defaulttests']
+          if masters:
+            return masters
+
     if not options.bot:
       parser.error('No default try builder to try, use --bot')