Issue 4581 - Update buildtools dependency

ensure_dependencies.py

 #!/usr/bin/env python
 
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 import sys
 import os
 import posixpath
 import re
@@ skipping 52 matching lines @@
         result = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()[0]
         return result.strip()
 
     def pull(self, repo):
         subprocess.check_call(['hg', 'pull', '--repository', repo, '--quiet'])
 
     def update(self, repo, rev, revname):
         subprocess.check_call(['hg', 'update', '--repository', repo, '--quiet', '--check', '--rev', rev])
 
     def ignore(self, target, repo):
+        config_path = os.path.join(repo, '.hg', 'hgrc')
+        ignore_file = os.path.join('.hg', 'dependencies')
+        ignore_path = os.path.join(repo, ignore_file)
 
-        if not self.istype(target):
+        config = RawConfigParser()
+        config.read(config_path)
 
-            config_path = os.path.join(repo, '.hg', 'hgrc')
-            ignore_path = os.path.abspath(os.path.join(repo, '.hg', 'dependencies'))
+        if not config.has_section('ui'):
+            config.add_section('ui')
 
-            config = RawConfigParser()
-            config.read(config_path)
+        config.set('ui', 'ignore.dependencies', ignore_file)
+        with open(config_path, 'w') as stream:
+            config.write(stream)
 
-            if not config.has_section('ui'):
-                config.add_section('ui')
-
-            config.set('ui', 'ignore.dependencies', ignore_path)
-            with open(config_path, 'w') as stream:
-                config.write(stream)
-
-            module = os.path.relpath(target, repo)
-            _ensure_line_exists(ignore_path, module)
+        module = os.path.relpath(target, repo)
+        _ensure_line_exists(ignore_path, module)
 
     def postprocess_url(self, url):
         return url
 
 
 class Git():
     def istype(self, repodir):
         return os.path.exists(os.path.join(repodir, '.git'))
 
     def clone(self, source, target):
@@ skipping 247 matching lines @@
                 handle.write(sourcedata)
             if __name__ == '__main__':
                 logging.info('Restarting %s' % target)
                 os.execv(sys.executable, [sys.executable, target] + sys.argv[1:])
             else:
                 logging.warning('Cannot restart %s automatically, please rerun' % target)
 
 
 def _ensure_line_exists(path, pattern):
     with open(path, 'a+') as f:
+        f.seek(0, os.SEEK_SET)
         file_content = [l.strip() for l in f.readlines()]
         if not pattern in file_content:
             file_content.append(pattern)
             f.seek(0, os.SEEK_SET)
             f.truncate()
             for l in file_content:
                 print >>f, l
 
 if __name__ == '__main__':
     logging.basicConfig(format='%(levelname)s: %(message)s', level=logging.INFO)
 
     parser = argparse.ArgumentParser(description='Verify dependencies for a set of repositories, by default the repository of this script.')
     parser.add_argument('repos', metavar='repository', type=str, nargs='*', help='Repository path')
     parser.add_argument('-q', '--quiet', action='store_true', help='Suppress informational output')
     args = parser.parse_args()
 
     if args.quiet:
         logging.disable(logging.INFO)
 
     repos = args.repos
     if not len(repos):
         repos = [os.path.dirname(__file__)]
     for repo in repos:
         resolve_deps(repo)