mac: Print an error when doing a branded build and the 10.6 sdk is not around

build/mac/find_sdk.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import os
 import re
 import subprocess
 import sys
 
 """Prints the lowest locally available SDK version greater than or equal to a
 given minimum sdk version to standard output.
 
 Usage:
   python find_sdk.py 10.6  # Ignores SDKs < 10.6
 """
 
+from optparse import OptionParser
+
+
 def parse_version(version_str):
   """'10.6' => [10, 6]"""
   return map(int, re.findall(r'(\d+)', version_str))
 
 
-def main(min_sdk_version):
+def main():
+  parser = OptionParser()
+  parser.add_option("--verify",
+                    action="store_true", dest="verify", default=False,
+                    help="return the sdk argument and warn if it doesn't exist")
+  (options, args) = parser.parse_args()
+  min_sdk_version = args[0]
+
   job = subprocess.Popen(['xcode-select', '-print-path'],
                          stdout=subprocess.PIPE,
                          stderr=subprocess.STDOUT)
   out, err = job.communicate()
   if job.returncode != 0:
     print >>sys.stderr, out
     print >>sys.stderr, err
     raise Exception(('Error %d running xcode-select, you might have to run '
       '|sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer| '
       'if you are using Xcode 4.') % job.returncode)
   # The Developer folder moved in Xcode 4.3.
   xcode43_sdk_path = os.path.join(
       out.rstrip(), 'Platforms/MacOSX.platform/Developer/SDKs')
   if os.path.isdir(xcode43_sdk_path):
     sdk_dir = xcode43_sdk_path
   else:
     sdk_dir = os.path.join(out.rstrip(), 'SDKs')
   sdks = [re.findall('^MacOSX(10\.\d+)\.sdk$', s) for s in os.listdir(sdk_dir)]
   sdks = [s[0] for s in sdks if s]  # [['10.5'], ['10.6']] => ['10.5', '10.6']
   sdks = [s for s in sdks  # ['10.5', '10.6'] => ['10.6']
           if parse_version(s) >= parse_version(min_sdk_version)]
   if not sdks:
     raise Exception('No %s+ SDK found' % min_sdk_version)
-  print sorted(sdks, key=parse_version)[0]
+  best_sdk = sorted(sdks, key=parse_version)[0]
+
+  if options.verify and best_sdk != min_sdk_version:
+    print >>sys.stderr, ''
+    print >>sys.stderr, '                                           vvvvvvv'
+    print >>sys.stderr, ''
+    print >>sys.stderr, \
+        'This build requires the %s SDK, but it was not found on your system.' \
+        % min_sdk_version
+    print >>sys.stderr, \
+        'Either install it, or explicitly set mac_sdk in your GYP_DEFINES.'
+    print >>sys.stderr, ''
+    print >>sys.stderr, '                                           ^^^^^^^'
+    print >>sys.stderr, ''
+    return min_sdk_version
+
+  return best_sdk
 
 
 if __name__ == '__main__':
   if sys.platform != 'darwin':
     raise Exception("This script only runs on Mac")
-  main(min_sdk_version=sys.argv[1])
+  print main()