--- a/.hgignore
+++ b/.hgignore
@@ -13,3 +13,7 @@ dist
 *.egg-info
 hgsubversion/__version__.py
 nbproject
+.project
+.pydevproject
+.settings
+*.orig

--- a/hgsubversion/maps.py
+++ b/hgsubversion/maps.py
@@ -5,6 +5,7 @@ from mercurial import util as hgutil
 from mercurial import node
 
 import svncommands
+import util
 
 class AuthorMap(dict):
     '''A mapping from Subversion-style authors to Mercurial-style
@@ -136,14 +137,14 @@ class Tags(dict):
             print 'tagmap too new -- please upgrade'
             raise NotImplementedError
         for l in f:
-            hash, revision, tag = l.split(' ', 2)
+            ha, revision, tag = l.split(' ', 2)
             revision = int(revision)
             tag = tag[:-1]
             if self.endrev is not None and revision > self.endrev:
                 break
             if not tag:
                 continue
-            dict.__setitem__(self, tag, node.bin(hash))
+            dict.__setitem__(self, tag, node.bin(ha))
         f.close()
 
     def _write(self):
@@ -168,11 +169,11 @@ class Tags(dict):
     def __setitem__(self, tag, info):
         if not tag:
             raise hgutil.Abort('tag cannot be empty')
-        hash, revision = info
+        ha, revision = info
         f = open(self.path, 'a')
-        f.write('%s %s %s\n' % (node.hex(hash), revision, tag))
+        f.write('%s %s %s\n' % (node.hex(ha), revision, tag))
         f.close()
-        dict.__setitem__(self, tag, hash)
+        dict.__setitem__(self, tag, ha)
 
 
 class RevMap(dict):
@@ -185,11 +186,10 @@ class RevMap(dict):
         self.ypath = os.path.join(repo.path, 'svn', 'lastpulled')
         # TODO(durin42): Consider moving management of the youngest
         # file to svnmeta itself rather than leaving it here.
-        self._youngest = 0
         # must load youngest file first, or else self._load() can
         # clobber the info
-        if os.path.isfile(self.ypath):
-            self._youngest = int(open(self.ypath).read().strip())
+        _yonngest_str = util.load_string(self.ypath, '0')
+        self._youngest = int(_yonngest_str.strip())
         self.oldest = 0
         if os.path.isfile(self.path):
             self._load()
@@ -198,9 +198,7 @@ class RevMap(dict):
 
     def _set_youngest(self, rev):
         self._youngest = max(self._youngest, rev)
-        fp = open(self.ypath, 'wb')
-        fp.write(str(self._youngest) + '\n')
-        fp.close()
+        util.save_string(self.ypath, str(self._youngest) + '\n')
 
     def _get_youngest(self):
         return self._youngest
@@ -221,7 +219,7 @@ class RevMap(dict):
             print 'revmap too new -- please upgrade'
             raise NotImplementedError
         for l in f:
-            revnum, hash, branch = l.split(' ', 2)
+            revnum, ha, branch = l.split(' ', 2)
             if branch == '\n':
                 branch = None
             else:
@@ -231,7 +229,7 @@ class RevMap(dict):
                 self.youngest = revnum
             if revnum < self.oldest or not self.oldest:
                 self.oldest = revnum
-            dict.__setitem__(self, (revnum, branch), node.bin(hash))
+            dict.__setitem__(self, (revnum, branch), node.bin(ha))
         f.close()
 
     def _write(self):
@@ -239,17 +237,17 @@ class RevMap(dict):
         f.write('%s\n' % self.VERSION)
         f.close()
 
-    def __setitem__(self, key, hash):
+    def __setitem__(self, key, ha):
         revnum, branch = key
         f = open(self.path, 'a')
         b = branch or ''
-        f.write(str(revnum) + ' ' + node.hex(hash) + ' ' + b + '\n')
+        f.write(str(revnum) + ' ' + node.hex(ha) + ' ' + b + '\n')
         f.close()
         if revnum > self.youngest or not self.youngest:
             self.youngest = revnum
         if revnum < self.oldest or not self.oldest:
             self.oldest = revnum
-        dict.__setitem__(self, (revnum, branch), hash)
+        dict.__setitem__(self, (revnum, branch), ha)
 
 
 class FileMap(object):
@@ -269,12 +267,12 @@ class FileMap(object):
             yield name[:e], name[e+1:]
             e = name.rfind('/', 0, e)
 
-    def check(self, map, path):
-        map = getattr(self, map)
-        for pre, suf in self._rpairs(path):
-            if pre not in map:
+    def check(self, m, path):
+        m = getattr(self, m)
+        for pre, _suf in self._rpairs(path):
+            if pre not in m:
                 continue
-            return map[pre]
+            return m[pre]
         return None
 
     def __contains__(self, path):
@@ -294,13 +292,13 @@ class FileMap(object):
     def __len__(self):
         return len(self.include) + len(self.exclude)
 
-    def add(self, fn, map, path):
-        mapping = getattr(self, map)
+    def add(self, fn, m, path):
+        mapping = getattr(self, m)
         if path in mapping:
             msg = 'duplicate %s entry in %s: "%s"\n'
-            self.ui.status(msg % (map, fn, path))
+            self.ui.status(msg % (m, fn, path))
             return
-        bits = map.strip('e'), path
+        bits = m.strip('e'), path
         self.ui.debug('%sing %s\n' % bits)
         mapping[path] = path
 

--- a/hgsubversion/svnexternals.py
+++ b/hgsubversion/svnexternals.py
@@ -17,7 +17,7 @@ try:
     canonpath = hgutil.canonpath
 except (ImportError, AttributeError):
     from mercurial import scmutil
-    canonpath = scmutil.canonpath    
+    canonpath = scmutil.canonpath
     passpegrev = False
 
 import util
@@ -59,7 +59,6 @@ class externalsfile(dict):
     def read(self, data):
         self.clear()
         fp = cStringIO.StringIO(data)
-        dirs = {}
         target = None
         for line in fp.readlines():
             if not line.strip():
@@ -232,7 +231,7 @@ class externalsupdater:
         if rev:
             revspec = ['-r', rev]
         if os.path.isdir(path):
-            exturl, extroot, extrev = getsvninfo(path)
+            exturl, _extroot, extrev = getsvninfo(path)
             # Comparing the source paths is not enough, but I don't
             # know how to compare path+pegrev. The following update
             # might fail if the path was replaced by another unrelated
@@ -347,7 +346,7 @@ def getchanges(ui, repo, parentctx, exts
         if exts:
             defs = parsedefinitions(ui, repo, '', exts)
             hgsub, hgsubstate = [], []
-            for path, rev, source, pegrev, norevline, base in sorted(defs):
+            for path, rev, _source, _pegrev, norevline, base in sorted(defs):
                 hgsub.append('%s = [hgsubversion] %s:%s\n'
                              % (path, base, norevline))
                 if rev is None:

--- a/hgsubversion/util.py
+++ b/hgsubversion/util.py
@@ -99,6 +99,29 @@ def normalize_url(url):
         url = '%s#%s' % (url, checkout)
     return url
 
+
+def load_string(file_path, default=None, limit=1024):
+    if not os.path.exists(file_path):
+        return default
+    try:
+        f = open(file_path, 'r')
+        ret = f.read(limit)
+        f.close()
+    except:
+        return default
+    if ret == '':
+        return default
+    return ret
+
+
+def save_string(file_path, string):
+    if string is None:
+        string = ""
+    f = open(file_path, 'wb')
+    f.write(str(string))
+    f.close()
+
+
 # TODO remove when we drop 1.3 support
 def progress(ui, *args, **kwargs):
     if getattr(ui, 'progress', False):

--- a/setup.py
+++ b/setup.py
@@ -72,7 +72,7 @@ elif os.path.exists('.hg_archival.txt'):
     kw = dict([t.strip() for t in l.split(':', 1)]
               for l in open('.hg_archival.txt'))
     if 'tag' in kw:
-        version =  kw['tag']
+        version = kw['tag']
     elif 'latesttag' in kw:
         version = '%(latesttag)s+%(latesttagdistance)s-%(node).12s' % kw
     else:
@@ -107,22 +107,22 @@ except ImportError:
     requires.append('subvertpy>=0.7.4')
 
 setup(
-    name = 'hgsubversion',
-    version = version,
-    url = 'http://bitbucket.org/durin42/hgsubversion',
-    license = 'GNU GPL',
-    author = 'Augie Fackler, others',
-    author_email = 'durin42@gmail.com',
-    description = ('hgsubversion is a Mercurial extension for working with '
+    name='hgsubversion',
+    version=version,
+    url='http://bitbucket.org/durin42/hgsubversion',
+    license='GNU GPL',
+    author='Augie Fackler, others',
+    author_email='durin42@gmail.com',
+    description=('hgsubversion is a Mercurial extension for working with '
                    'Subversion repositories.'),
-    long_description = open(os.path.join(os.path.dirname(__file__),
+    long_description=open(os.path.join(os.path.dirname(__file__),
                                          'README')).read(),
-    keywords = 'mercurial',
-    packages = ('hgsubversion', 'hgsubversion.svnwrap'),
-    package_data = { 'hgsubversion': ['help/subversion.rst'] },
-    platforms = 'any',
+    keywords='mercurial',
+    packages=('hgsubversion', 'hgsubversion.svnwrap'),
+    package_data={ 'hgsubversion': ['help/subversion.rst'] },
+    platforms='any',
     install_requires=requires,
-    classifiers = [
+    classifiers=[
         'License :: OSI Approved :: GNU General Public License (GPL)',
         'Intended Audience :: Developers',
         'Topic :: Software Development :: Version Control',
@@ -130,5 +130,5 @@ setup(
         'Programming Language :: Python',
         'Operating System :: OS Independent',
     ],
-    cmdclass = {'build_py': build_py},
+    cmdclass={'build_py': build_py},
 )