Do no delete file if they exist, even if p.is_new is True.

checkout.py

 # coding=utf8
 # Copyright (c) 2011 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.
 """Manages a project checkout.
 
 Includes support for svn, git-svn and git.
 """
 
 from __future__ import with_statement
@@ skipping 105 matching lines @@
       try:
         stdout = ''
         filename = os.path.join(self.project_path, p.filename)
         if p.is_delete:
           os.remove(filename)
         else:
           dirname = os.path.dirname(p.filename)
           full_dir = os.path.join(self.project_path, dirname)
           if dirname and not os.path.isdir(full_dir):
             os.makedirs(full_dir)
+
+          filepath = os.path.join(self.project_path, p.filename)
           if p.is_binary:
-            with open(os.path.join(filename), 'wb') as f:
+            with open(filepath, 'wb') as f:
               f.write(p.get())
           else:
             if p.diff_hunks:
               stdout = subprocess2.check_output(
                   ['patch', '-p%s' % p.patchlevel],
                   stdin=p.get(),
                   cwd=self.project_path)
-            elif p.is_new:
+            elif p.is_new and not os.path.exists(filepath):
               # There is only a header. Just create the file.
-              open(os.path.join(self.project_path, p.filename), 'w').close()
+              open(filepath, 'w').close()
         for post in post_processor:
           post(self, p)
       except OSError, e:
         raise PatchApplicationFailed(p.filename, '%s%s' % (stdout, e))
       except subprocess.CalledProcessError, e:
         raise PatchApplicationFailed(
             p.filename, '%s%s' % (stdout, getattr(e, 'stdout', None)))
 
   def commit(self, commit_message, user):
     """Stubbed out."""
@@ skipping 121 matching lines @@
           dirs_to_create = []
           while (dirname and
               not os.path.isdir(os.path.join(self.project_path, dirname))):
             dirs_to_create.append(dirname)
             dirname = os.path.dirname(dirname)
           for dir_to_create in reversed(dirs_to_create):
             os.mkdir(os.path.join(self.project_path, dir_to_create))
             stdout += self._check_output_svn(
                 ['add', dir_to_create, '--force'], credentials=False)
 
+          filepath = os.path.join(self.project_path, p.filename)
           if p.is_binary:
-            with open(os.path.join(self.project_path, p.filename), 'wb') as f:
+            with open(filepath, 'wb') as f:
               f.write(p.get())
           else:
             if p.diff_hunks:
               cmd = ['patch', '-p%s' % p.patchlevel, '--forward', '--force']
               stdout += subprocess2.check_output(
                   cmd, stdin=p.get(), cwd=self.project_path)
-            elif p.is_new:
-              # There is only a header. Just create the file.
-              open(os.path.join(self.project_path, p.filename), 'w').close()
+            elif p.is_new and not os.path.exists(filepath):
+              # There is only a header. Just create the file if it doesn't
+              # exist.
+              open(filepath, 'w').close()
           if p.is_new:
             stdout += self._check_output_svn(
                 ['add', p.filename, '--force'], credentials=False)
           for prop in p.svn_properties:
             stdout += self._check_output_svn(
                 ['propset', prop[0], prop[1], p.filename], credentials=False)
           for prop, values in self.svn_config.auto_props.iteritems():
             if fnmatch.fnmatch(p.filename, prop):
               for value in values.split(';'):
                 if '=' not in value:
@@ skipping 367 matching lines @@
         user, message))
     return 'FAKE'
 
   @property
   def project_name(self):
     return self.checkout.project_name
 
   @property
   def project_path(self):
     return self.checkout.project_path