[NaCl SDK] Make verification failures a little easier to read.

native_client_sdk/src/build_tools/build_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.
 
 """Entry point for both build and try bots.
 
 This script is invoked from XXX, usually without arguments
 to package an SDK. It automatically determines whether
 this SDK is for mac, win, linux.
@@ skipping 733 matching lines @@
     license_files += [os.path.join(fileroot, f) for f in extra_files]
   print '\n'.join(license_files)
 
   if not os.path.isabs(output_filename):
     output_filename = os.path.join(fileroot, output_filename)
   generate_notice.Generate(output_filename, fileroot, license_files)
 
 
 def BuildStepVerifyFilelist(pepperdir, platform):
   buildbot_common.BuildStep('Verify SDK Files')
-  verify_filelist.Verify(platform, os.path.join(SCRIPT_DIR, 'sdk_files.list'),
-                         pepperdir)
-  print 'OK'
+  file_list_path = os.path.join(SCRIPT_DIR, 'sdk_files.list')
+  try:
+    verify_filelist.Verify(platform, file_list_path, pepperdir)
+    print 'OK'
+  except verify_filelist.ParseException, e:
+    buildbot_common.ErrorExit('Parsing sdk_files.list failed:\n\n%s' % e)
+  except verify_filelist.VerifyException, e:
+    file_list_rel = os.path.relpath(file_list_path)
+    verify_filelist_py = os.path.splitext(verify_filelist.__file__)[0] + '.py'
+    verify_filelist_py = os.path.relpath(verify_filelist_py)
+    pepperdir_rel = os.path.relpath(pepperdir)
+
+    msg = """\
+SDK verification failed:
+
+%s
+Add/remove files from %s to fix.
+
+Run:
+    ./%s %s %s
+to test.""" % (e, file_list_rel, verify_filelist_py, file_list_rel,
+               pepperdir_rel)
+    buildbot_common.ErrorExit(msg)
+
 
 
 def BuildStepTarBundle(pepper_ver, tarfile):
   buildbot_common.BuildStep('Tar Pepper Bundle')
   buildbot_common.MakeDir(os.path.dirname(tarfile))
   buildbot_common.Run([sys.executable, CYGTAR, '-C', OUT_DIR, '-cjf', tarfile,
        'pepper_' + pepper_ver], cwd=NACL_DIR)
 
 
 
@@ skipping 207 matching lines @@
     BuildStepArchiveSDKTools()
 
   return 0
 
 
 if __name__ == '__main__':
   try:
     sys.exit(main(sys.argv))
   except KeyboardInterrupt:
     buildbot_common.ErrorExit('build_sdk: interrupted')