Support for |change| argument to |GetPreferredTrySlaves()|, try 2.

presubmit_support.py

Index: presubmit_support.py
===================================================================
--- presubmit_support.py	(revision 102922)
+++ presubmit_support.py	(working copy)
@@ -16,6 +16,7 @@
 import cStringIO  # Exposed through the API.
 import fnmatch
 import glob
+import inspect
 import logging
 import marshal  # Exposed through the API.
 import optparse
@@ -875,7 +876,7 @@
 
 class GetTrySlavesExecuter(object):
   @staticmethod
-  def ExecPresubmitScript(script_text, presubmit_path, project):
+  def ExecPresubmitScript(script_text, presubmit_path, project, change):
     """Executes GetPreferredTrySlaves() from a single presubmit script.
 
     Args:
@@ -894,10 +895,14 @@
 
     function_name = 'GetPreferredTrySlaves'
     if function_name in context:
-      try:
-        result = eval(function_name + '(' + repr(project) + ')', context)
-      except TypeError:
-        result = eval(function_name + '()', context)
+      get_preferred_try_slaves = context[function_name]
+      function_info = inspect.getargspec(get_preferred_try_slaves)
+      if len(function_info[0]) == 1:
+        result = get_preferred_try_slaves(project)
+      elif len(function_info[0]) == 2:
+        result = get_preferred_try_slaves(project, change)
+      else:
+        result = get_preferred_try_slaves()
       if not isinstance(result, types.ListType):
         raise PresubmitFailure(
             'Presubmit functions must return a list, got a %s instead: %s' %
@@ -913,7 +918,8 @@
     return result
 
 
-def DoGetTrySlaves(changed_files,
+def DoGetTrySlaves(change,
+                   changed_files,
                    repository_root,
                    default_presubmit,
                    project,
@@ -942,7 +948,7 @@
       output_stream.write("Running default presubmit script.\n")
     fake_path = os.path.join(repository_root, 'PRESUBMIT.py')
     results += executer.ExecPresubmitScript(
-        default_presubmit, fake_path, project)
+        default_presubmit, fake_path, project, change)
   for filename in presubmit_files:
     filename = os.path.abspath(filename)
     if verbose:
@@ -950,7 +956,7 @@
     # Accept CRLF presubmit script.
     presubmit_script = gclient_utils.FileRead(filename, 'rU')
     results += executer.ExecPresubmitScript(
-        presubmit_script, filename, project)
+        presubmit_script, filename, project, change)
 
   slaves = list(set(results))
   if slaves and verbose: