Fix compatibility for gcl-try/git-try with repos not using tryserver.chromium

trychange.py

Index: trychange.py
diff --git a/trychange.py b/trychange.py
index 6b0c8af646a4f56a1e4086fbf9aac6223f3ca6cf..a056bbd03c5c0bb98e174e7d6cba64e467705fb8 100755
--- a/trychange.py
+++ b/trychange.py
@@ -376,14 +376,23 @@ def _GenTSBotSpec(checkouts, change, changed_files, options):
                                         options.issue,
                                         options.patchset,
                                         options.email)
-    trybots = presubmit_support.DoGetTryMasters(
+    masters = presubmit_support.DoGetTryMasters(
         change,
         checkouts[0].GetFileNames(),
         checkouts[0].checkout_root,
         root_presubmit,
         options.project,
         options.verbose,
-        sys.stdout).get('tryserver.chromium', [])
+        sys.stdout)
+
+    # Compatibility for old checkouts and bots that were on tryserver.chromium.
+    trybots = masters.get('tryserver.chromium', [])
+
+    # Compatibility for checkouts that are not using tryserver.chromium
+    # but are stuck with git-try or gcl-try.
+    if not trybots and len(masters) == 1:

[smut, 2014/03/20 00:15:02]

This is getting really hacky, and I hope this covers all cases. Could a
presubmit script ever return multiple masters, none of which are
tryserver.chromium?

[Paweł Hajdan Jr., 2014/03/20 00:27:01]

Yes.

+      trybots = masters[masters.keys()[0]]

[smut, 2014/03/20 00:15:02]

There's also "trybots = masters.values()[0]", but it probably doesn't matter.

[Paweł Hajdan Jr., 2014/03/20 00:27:01]

Oh, indeed, thanks for suggestion.

+
     if trybots:
       old_style = filter(lambda x: isinstance(x, basestring), trybots)
       new_style = filter(lambda x: isinstance(x, tuple), trybots)