pep8: fixed issue with shadowing reserved python variables.

vcsserver/hg.py

@@ -1,724 +1,724 b''
 # RhodeCode VCSServer provides access to different vcs backends via network.
 # Copyright (C) 2014-2016 RodeCode GmbH
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
 
 import io
 import logging
 import stat
 import sys
 import urllib
 import urllib2
 
 from hgext import largefiles, rebase
 from hgext.strip import strip as hgext_strip
 from mercurial import commands
 from mercurial import unionrepo
 
 from vcsserver import exceptions
 from vcsserver.base import RepoFactory, obfuscate_qs
 from vcsserver.hgcompat import (
     archival, bin, clone, config as hgconfig, diffopts, hex,
     hg_url as url_parser, httpbasicauthhandler, httpdigestauthhandler,
     httppeer, localrepository, match, memctx, exchange, memfilectx, nullrev,
     patch, peer, revrange, ui, Abort, LookupError, RepoError, RepoLookupError,
     InterventionRequired, RequirementError)
 
 log = logging.getLogger(__name__)
 
 
 def make_ui_from_config(repo_config):
     baseui = ui.ui()
 
     # clean the baseui object
     baseui._ocfg = hgconfig.config()
     baseui._ucfg = hgconfig.config()
     baseui._tcfg = hgconfig.config()
 
     for section, option, value in repo_config:
         baseui.setconfig(section, option, value)
 
     # make our hgweb quiet so it doesn't print output
     baseui.setconfig('ui', 'quiet', 'true')
 
     # force mercurial to only use 1 thread, otherwise it may try to set a
     # signal in a non-main thread, thus generating a ValueError.
     baseui.setconfig('worker', 'numcpus', 1)
 
     # If there is no config for the largefiles extension, we explicitly disable
     # it here. This overrides settings from repositories hgrc file. Recent
     # mercurial versions enable largefiles in hgrc on clone from largefile
     # repo.
     if not baseui.hasconfig('extensions', 'largefiles'):
         log.debug('Explicitly disable largefiles extension for repo.')
         baseui.setconfig('extensions', 'largefiles', '!')
 
     return baseui
 
 
 def reraise_safe_exceptions(func):
     """Decorator for converting mercurial exceptions to something neutral."""
     def wrapper(*args, **kwargs):
         try:
             return func(*args, **kwargs)
         except (Abort, InterventionRequired):
             raise_from_original(exceptions.AbortException)
         except RepoLookupError:
             raise_from_original(exceptions.LookupException)
         except RequirementError:
             raise_from_original(exceptions.RequirementException)
         except RepoError:
             raise_from_original(exceptions.VcsException)
         except LookupError:
             raise_from_original(exceptions.LookupException)
         except Exception as e:
             if not hasattr(e, '_vcs_kind'):
                 log.exception("Unhandled exception in hg remote call")
                 raise_from_original(exceptions.UnhandledException)
             raise
     return wrapper
 
 
 def raise_from_original(new_type):
     """
     Raise a new exception type with original args and traceback.
     """
     _, original, traceback = sys.exc_info()
     try:
         raise new_type(*original.args), None, traceback
     finally:
         del traceback
 
 
 class MercurialFactory(RepoFactory):
 
     def _create_config(self, config, hooks=True):
         if not hooks:
             hooks_to_clean = frozenset((
                 'changegroup.repo_size', 'preoutgoing.pre_pull',
                 'outgoing.pull_logger', 'prechangegroup.pre_push'))
             new_config = []
             for section, option, value in config:
                 if section == 'hooks' and option in hooks_to_clean:
                     continue
                 new_config.append((section, option, value))
             config = new_config
 
         baseui = make_ui_from_config(config)
         return baseui
 
     def _create_repo(self, wire, create):
         baseui = self._create_config(wire["config"])
         return localrepository(baseui, wire["path"], create)
 
 
 class HgRemote(object):
 
     def __init__(self, factory):
         self._factory = factory
 
         self._bulk_methods = {
             "affected_files": self.ctx_files,
             "author": self.ctx_user,
             "branch": self.ctx_branch,
             "children": self.ctx_children,
             "date": self.ctx_date,
             "message": self.ctx_description,
             "parents": self.ctx_parents,
             "status": self.ctx_status,
             "_file_paths": self.ctx_list,
         }
 
     @reraise_safe_exceptions
     def discover_hg_version(self):
         from mercurial import util
         return util.version()
 
     @reraise_safe_exceptions
     def archive_repo(self, archive_path, mtime, file_info, kind):
         if kind == "tgz":
             archiver = archival.tarit(archive_path, mtime, "gz")
         elif kind == "tbz2":
             archiver = archival.tarit(archive_path, mtime, "bz2")
         elif kind == 'zip':
             archiver = archival.zipit(archive_path, mtime)
         else:
             raise exceptions.ArchiveException(
                 'Remote does not support: "%s".' % kind)
 
         for f_path, f_mode, f_is_link, f_content in file_info:
             archiver.addfile(f_path, f_mode, f_is_link, f_content)
         archiver.done()
 
     @reraise_safe_exceptions
     def bookmarks(self, wire):
         repo = self._factory.repo(wire)
         return dict(repo._bookmarks)
 
     @reraise_safe_exceptions
     def branches(self, wire, normal, closed):
         repo = self._factory.repo(wire)
         iter_branches = repo.branchmap().iterbranches()
         bt = {}
         for branch_name, _heads, tip, is_closed in iter_branches:
             if normal and not is_closed:
                 bt[branch_name] = tip
             if closed and is_closed:
                 bt[branch_name] = tip
 
         return bt
 
     @reraise_safe_exceptions
     def bulk_request(self, wire, rev, pre_load):
         result = {}
         for attr in pre_load:
             try:
                 method = self._bulk_methods[attr]
                 result[attr] = method(wire, rev)
             except KeyError:
                 raise exceptions.VcsException(
                     'Unknown bulk attribute: "%s"' % attr)
         return result
 
     @reraise_safe_exceptions
     def clone(self, wire, source, dest, update_after_clone=False, hooks=True):
         baseui = self._factory._create_config(wire["config"], hooks=hooks)
         clone(baseui, source, dest, noupdate=not update_after_clone)
 
     @reraise_safe_exceptions
     def commitctx(
             self, wire, message, parents, commit_time, commit_timezone,
             user, files, extra, removed, updated):
 
         def _filectxfn(_repo, memctx, path):
             """
             Marks given path as added/changed/removed in a given _repo. This is
             for internal mercurial commit function.
             """
 
             # check if this path is removed
             if path in removed:
                 # returning None is a way to mark node for removal
                 return None
 
             # check if this path is added
             for node in updated:
                 if node['path'] == path:
                     return memfilectx(
                         _repo,
                         path=node['path'],
                         data=node['content'],
                         islink=False,
                         isexec=bool(node['mode'] & stat.S_IXUSR),
                         copied=False,
                         memctx=memctx)
 
             raise exceptions.AbortException(
                 "Given path haven't been marked as added, "
                 "changed or removed (%s)" % path)
 
         repo = self._factory.repo(wire)
 
         commit_ctx = memctx(
             repo=repo,
             parents=parents,
             text=message,
             files=files,
             filectxfn=_filectxfn,
             user=user,
             date=(commit_time, commit_timezone),
             extra=extra)
 
         n = repo.commitctx(commit_ctx)
         new_id = hex(n)
 
         return new_id
 
     @reraise_safe_exceptions
     def ctx_branch(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         return ctx.branch()
 
     @reraise_safe_exceptions
     def ctx_children(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         return [child.rev() for child in ctx.children()]
 
     @reraise_safe_exceptions
     def ctx_date(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         return ctx.date()
 
     @reraise_safe_exceptions
     def ctx_description(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         return ctx.description()
 
     @reraise_safe_exceptions
     def ctx_diff(
             self, wire, revision, git=True, ignore_whitespace=True, context=3):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         result = ctx.diff(
             git=git, ignore_whitespace=ignore_whitespace, context=context)
         return list(result)
 
     @reraise_safe_exceptions
     def ctx_files(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         return ctx.files()
 
     @reraise_safe_exceptions
     def ctx_list(self, path, revision):
         repo = self._factory.repo(path)
         ctx = repo[revision]
         return list(ctx)
 
     @reraise_safe_exceptions
     def ctx_parents(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         return [parent.rev() for parent in ctx.parents()]
 
     @reraise_safe_exceptions
     def ctx_substate(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         return ctx.substate
 
     @reraise_safe_exceptions
     def ctx_status(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         status = repo[ctx.p1().node()].status(other=ctx.node())
         # object of status (odd, custom named tuple in mercurial) is not
         # correctly serializable via Pyro, we make it a list, as the underling
         # API expects this to be a list
         return list(status)
 
     @reraise_safe_exceptions
     def ctx_user(self, wire, revision):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         return ctx.user()
 
     @reraise_safe_exceptions
     def check_url(self, url, config):
         _proto = None
         if '+' in url[:url.find('://')]:
             _proto = url[0:url.find('+')]
             url = url[url.find('+') + 1:]
         handlers = []
         url_obj = url_parser(url)
         test_uri, authinfo = url_obj.authinfo()
         url_obj.passwd = '*****' if url_obj.passwd else url_obj.passwd
         url_obj.query = obfuscate_qs(url_obj.query)
 
         cleaned_uri = str(url_obj)
         log.info("Checking URL for remote cloning/import: %s", cleaned_uri)
 
         if authinfo:
             # create a password manager
             passmgr = urllib2.HTTPPasswordMgrWithDefaultRealm()
             passmgr.add_password(*authinfo)
 
             handlers.extend((httpbasicauthhandler(passmgr),
                              httpdigestauthhandler(passmgr)))
 
         o = urllib2.build_opener(*handlers)
         o.addheaders = [('Content-Type', 'application/mercurial-0.1'),
                         ('Accept', 'application/mercurial-0.1')]
 
         q = {"cmd": 'between'}
         q.update({'pairs': "%s-%s" % ('0' * 40, '0' * 40)})
         qs = '?%s' % urllib.urlencode(q)
         cu = "%s%s" % (test_uri, qs)
         req = urllib2.Request(cu, None, {})
 
         try:
             log.debug("Trying to open URL %s", cleaned_uri)
             resp = o.open(req)
             if resp.code != 200:
                 raise exceptions.URLError('Return Code is not 200')
         except Exception as e:
             log.warning("URL cannot be opened: %s", cleaned_uri, exc_info=True)
             # means it cannot be cloned
             raise exceptions.URLError("[%s] org_exc: %s" % (cleaned_uri, e))
 
         # now check if it's a proper hg repo, but don't do it for svn
         try:
             if _proto == 'svn':
                 pass
             else:
                 # check for pure hg repos
                 log.debug(
                     "Verifying if URL is a Mercurial repository: %s",
                     cleaned_uri)
                 httppeer(make_ui_from_config(config), url).lookup('tip')
         except Exception as e:
             log.warning("URL is not a valid Mercurial repository: %s",
                         cleaned_uri)
             raise exceptions.URLError(
                 "url [%s] does not look like an hg repo org_exc: %s"
                 % (cleaned_uri, e))
 
         log.info("URL is a valid Mercurial repository: %s", cleaned_uri)
         return True
 
     @reraise_safe_exceptions
     def diff(
             self, wire, rev1, rev2, file_filter, opt_git, opt_ignorews,
             context):
         repo = self._factory.repo(wire)
 
         if file_filter:
-            filter = match(file_filter[0], '', [file_filter[1]])
+            match_filter = match(file_filter[0], '', [file_filter[1]])
         else:
-            filter = file_filter
+            match_filter = file_filter
         opts = diffopts(git=opt_git, ignorews=opt_ignorews, context=context)
 
         try:
             return "".join(patch.diff(
-                repo, node1=rev1, node2=rev2, match=filter, opts=opts))
+                repo, node1=rev1, node2=rev2, match=match_filter, opts=opts))
         except RepoLookupError:
             raise exceptions.LookupException()
 
     @reraise_safe_exceptions
     def file_history(self, wire, revision, path, limit):
         repo = self._factory.repo(wire)
 
         ctx = repo[revision]
         fctx = ctx.filectx(path)
 
         def history_iter():
             limit_rev = fctx.rev()
             for obj in reversed(list(fctx.filelog())):
                 obj = fctx.filectx(obj)
                 if limit_rev >= obj.rev():
                     yield obj
 
         history = []
         for cnt, obj in enumerate(history_iter()):
             if limit and cnt >= limit:
                 break
             history.append(hex(obj.node()))
 
         return [x for x in history]
 
     @reraise_safe_exceptions
     def file_history_untill(self, wire, revision, path, limit):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         fctx = ctx.filectx(path)
 
         file_log = list(fctx.filelog())
         if limit:
             # Limit to the last n items
             file_log = file_log[-limit:]
 
         return [hex(fctx.filectx(cs).node()) for cs in reversed(file_log)]
 
     @reraise_safe_exceptions
     def fctx_annotate(self, wire, revision, path):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         fctx = ctx.filectx(path)
 
         result = []
         for i, annotate_data in enumerate(fctx.annotate()):
             ln_no = i + 1
             node_info, content = annotate_data
             sha = hex(node_info[0].node())
             result.append((ln_no, sha, content))
         return result
 
     @reraise_safe_exceptions
     def fctx_data(self, wire, revision, path):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         fctx = ctx.filectx(path)
         return fctx.data()
 
     @reraise_safe_exceptions
     def fctx_flags(self, wire, revision, path):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         fctx = ctx.filectx(path)
         return fctx.flags()
 
     @reraise_safe_exceptions
     def fctx_size(self, wire, revision, path):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         fctx = ctx.filectx(path)
         return fctx.size()
 
     @reraise_safe_exceptions
     def get_all_commit_ids(self, wire, name):
         repo = self._factory.repo(wire)
         revs = repo.filtered(name).changelog.index
         return map(lambda x: hex(x[7]), revs)[:-1]
 
     @reraise_safe_exceptions
     def get_config_value(self, wire, section, name, untrusted=False):
         repo = self._factory.repo(wire)
         return repo.ui.config(section, name, untrusted=untrusted)
 
     @reraise_safe_exceptions
     def get_config_bool(self, wire, section, name, untrusted=False):
         repo = self._factory.repo(wire)
         return repo.ui.configbool(section, name, untrusted=untrusted)
 
     @reraise_safe_exceptions
     def get_config_list(self, wire, section, name, untrusted=False):
         repo = self._factory.repo(wire)
         return repo.ui.configlist(section, name, untrusted=untrusted)
 
     @reraise_safe_exceptions
     def is_large_file(self, wire, path):
         return largefiles.lfutil.isstandin(path)
 
     @reraise_safe_exceptions
     def in_store(self, wire, sha):
         repo = self._factory.repo(wire)
         return largefiles.lfutil.instore(repo, sha)
 
     @reraise_safe_exceptions
     def in_user_cache(self, wire, sha):
         repo = self._factory.repo(wire)
         return largefiles.lfutil.inusercache(repo.ui, sha)
 
     @reraise_safe_exceptions
     def store_path(self, wire, sha):
         repo = self._factory.repo(wire)
         return largefiles.lfutil.storepath(repo, sha)
 
     @reraise_safe_exceptions
     def link(self, wire, sha, path):
         repo = self._factory.repo(wire)
         largefiles.lfutil.link(
             largefiles.lfutil.usercachepath(repo.ui, sha), path)
 
     @reraise_safe_exceptions
     def localrepository(self, wire, create=False):
         self._factory.repo(wire, create=create)
 
     @reraise_safe_exceptions
     def lookup(self, wire, revision, both):
         # TODO Paris: Ugly hack to "deserialize" long for msgpack
         if isinstance(revision, float):
             revision = long(revision)
         repo = self._factory.repo(wire)
         try:
             ctx = repo[revision]
         except RepoLookupError:
             raise exceptions.LookupException(revision)
         except LookupError as e:
             raise exceptions.LookupException(e.name)
 
         if not both:
             return ctx.hex()
 
         ctx = repo[ctx.hex()]
         return ctx.hex(), ctx.rev()
 
     @reraise_safe_exceptions
     def pull(self, wire, url, commit_ids=None):
         repo = self._factory.repo(wire)
         remote = peer(repo, {}, url)
         if commit_ids:
             commit_ids = [bin(commit_id) for commit_id in commit_ids]
 
         return exchange.pull(
             repo, remote, heads=commit_ids, force=None).cgresult
 
     @reraise_safe_exceptions
     def revision(self, wire, rev):
         repo = self._factory.repo(wire)
         ctx = repo[rev]
         return ctx.rev()
 
     @reraise_safe_exceptions
     def rev_range(self, wire, filter):
         repo = self._factory.repo(wire)
         revisions = [rev for rev in revrange(repo, filter)]
         return revisions
 
     @reraise_safe_exceptions
     def rev_range_hash(self, wire, node):
         repo = self._factory.repo(wire)
 
         def get_revs(repo, rev_opt):
             if rev_opt:
                 revs = revrange(repo, rev_opt)
                 if len(revs) == 0:
                     return (nullrev, nullrev)
                 return max(revs), min(revs)
             else:
                 return len(repo) - 1, 0
 
         stop, start = get_revs(repo, [node + ':'])
         revs = [hex(repo[r].node()) for r in xrange(start, stop + 1)]
         return revs
 
     @reraise_safe_exceptions
     def revs_from_revspec(self, wire, rev_spec, *args, **kwargs):
         other_path = kwargs.pop('other_path', None)
 
         # case when we want to compare two independent repositories
         if other_path and other_path != wire["path"]:
             baseui = self._factory._create_config(wire["config"])
             repo = unionrepo.unionrepository(baseui, other_path, wire["path"])
         else:
             repo = self._factory.repo(wire)
         return list(repo.revs(rev_spec, *args))
 
     @reraise_safe_exceptions
     def strip(self, wire, revision, update, backup):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         hgext_strip(
             repo.baseui, repo, ctx.node(), update=update, backup=backup)
 
     @reraise_safe_exceptions
     def tag(self, wire, name, revision, message, local, user,
             tag_time, tag_timezone):
         repo = self._factory.repo(wire)
         ctx = repo[revision]
         node = ctx.node()
 
         date = (tag_time, tag_timezone)
         try:
             repo.tag(name, node, message, local, user, date)
         except Abort:
             log.exception("Tag operation aborted")
             raise exceptions.AbortException()
 
     @reraise_safe_exceptions
     def tags(self, wire):
         repo = self._factory.repo(wire)
         return repo.tags()
 
     @reraise_safe_exceptions
     def update(self, wire, node=None, clean=False):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         commands.update(baseui, repo, node=node, clean=clean)
 
     @reraise_safe_exceptions
     def identify(self, wire):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         output = io.BytesIO()
         baseui.write = output.write
         # This is required to get a full node id
         baseui.debugflag = True
         commands.identify(baseui, repo, id=True)
 
         return output.getvalue()
 
     @reraise_safe_exceptions
     def pull_cmd(self, wire, source, bookmark=None, branch=None, revision=None,
                  hooks=True):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'], hooks=hooks)
 
         # Mercurial internally has a lot of logic that checks ONLY if
         # option is defined, we just pass those if they are defined then
         opts = {}
         if bookmark:
             opts['bookmark'] = bookmark
         if branch:
             opts['branch'] = branch
         if revision:
             opts['rev'] = revision
 
         commands.pull(baseui, repo, source, **opts)
 
     @reraise_safe_exceptions
     def heads(self, wire, branch=None):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         output = io.BytesIO()
 
         def write(data, **unused_kwargs):
             output.write(data)
 
         baseui.write = write
         if branch:
             args = [branch]
         else:
             args = []
         commands.heads(baseui, repo, template='{node} ', *args)
 
         return output.getvalue()
 
     @reraise_safe_exceptions
     def ancestor(self, wire, revision1, revision2):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         output = io.BytesIO()
         baseui.write = output.write
         commands.debugancestor(baseui, repo, revision1, revision2)
 
         return output.getvalue()
 
     @reraise_safe_exceptions
     def push(self, wire, revisions, dest_path, hooks=True,
              push_branches=False):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'], hooks=hooks)
         commands.push(baseui, repo, dest=dest_path, rev=revisions,
                       new_branch=push_branches)
 
     @reraise_safe_exceptions
     def merge(self, wire, revision):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         repo.ui.setconfig('ui', 'merge', 'internal:dump')
 
         # In case of sub repositories are used mercurial prompts the user in
         # case of merge conflicts or different sub repository sources. By
         # setting the interactive flag to `False` mercurial doesn't prompt the
         # used but instead uses a default value.
         repo.ui.setconfig('ui', 'interactive', False)
 
         commands.merge(baseui, repo, rev=revision)
 
     @reraise_safe_exceptions
     def commit(self, wire, message, username):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         repo.ui.setconfig('ui', 'username', username)
         commands.commit(baseui, repo, message=message)
 
     @reraise_safe_exceptions
     def rebase(self, wire, source=None, dest=None, abort=False):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         repo.ui.setconfig('ui', 'merge', 'internal:dump')
         rebase.rebase(
             baseui, repo, base=source, dest=dest, abort=abort, keep=not abort)
 
     @reraise_safe_exceptions
     def bookmark(self, wire, bookmark, revision=None):
         repo = self._factory.repo(wire)
         baseui = self._factory._create_config(wire['config'])
         commands.bookmark(baseui, repo, bookmark, rev=revision, force=True)

vcsserver/svn_diff.py

@@ -1,207 +1,209 b''
 # -*- coding: utf-8 -*-
 #
 # Copyright (C) 2004-2009 Edgewall Software
 # Copyright (C) 2004-2006 Christopher Lenz <[e-mail]>
 # All rights reserved.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
 # are also available at http://trac.edgewall.org/wiki/TracLicense.
 #
 # This software consists of voluntary contributions made by many
 # individuals. For the exact contribution history, see the revision
 # history and logs, available at http://trac.edgewall.org/log/.
 #
 # Author: Christopher Lenz <[e-mail]>
 
 import difflib
 
 
 def get_filtered_hunks(fromlines, tolines, context=None,
                        ignore_blank_lines=False, ignore_case=False,
                        ignore_space_changes=False):
     """Retrieve differences in the form of `difflib.SequenceMatcher`
     opcodes, grouped according to the ``context`` and ``ignore_*``
     parameters.
 
     :param fromlines: list of lines corresponding to the old content
     :param tolines: list of lines corresponding to the new content
     :param ignore_blank_lines: differences about empty lines only are ignored
     :param ignore_case: upper case / lower case only differences are ignored
     :param ignore_space_changes: differences in amount of spaces are ignored
     :param context: the number of "equal" lines kept for representing
                     the context of the change
     :return: generator of grouped `difflib.SequenceMatcher` opcodes
 
     If none of the ``ignore_*`` parameters is `True`, there's nothing
     to filter out the results will come straight from the
     SequenceMatcher.
     """
     hunks = get_hunks(fromlines, tolines, context)
     if ignore_space_changes or ignore_case or ignore_blank_lines:
         hunks = filter_ignorable_lines(hunks, fromlines, tolines, context,
                                        ignore_blank_lines, ignore_case,
                                        ignore_space_changes)
     return hunks
 
 
 def get_hunks(fromlines, tolines, context=None):
     """Generator yielding grouped opcodes describing differences .
 
     See `get_filtered_hunks` for the parameter descriptions.
     """
     matcher = difflib.SequenceMatcher(None, fromlines, tolines)
     if context is None:
         return (hunk for hunk in [matcher.get_opcodes()])
     else:
         return matcher.get_grouped_opcodes(context)
 
 
 def filter_ignorable_lines(hunks, fromlines, tolines, context,
                            ignore_blank_lines, ignore_case,
                            ignore_space_changes):
     """Detect line changes that should be ignored and emits them as
     tagged as "equal", possibly joined with the preceding and/or
     following "equal" block.
 
     See `get_filtered_hunks` for the parameter descriptions.
     """
     def is_ignorable(tag, fromlines, tolines):
         if tag == 'delete' and ignore_blank_lines:
             if ''.join(fromlines) == '':
                 return True
         elif tag == 'insert' and ignore_blank_lines:
             if ''.join(tolines) == '':
                 return True
         elif tag == 'replace' and (ignore_case or ignore_space_changes):
             if len(fromlines) != len(tolines):
                 return False
-            def f(str):
+
+            def f(input_str):
                 if ignore_case:
-                    str = str.lower()
+                    input_str = input_str.lower()
                 if ignore_space_changes:
-                    str = ' '.join(str.split())
-                return str
+                    input_str = ' '.join(input_str.split())
+                return input_str
+
             for i in range(len(fromlines)):
                 if f(fromlines[i]) != f(tolines[i]):
                     return False
             return True
 
     hunks = list(hunks)
     opcodes = []
     ignored_lines = False
     prev = None
     for hunk in hunks:
         for tag, i1, i2, j1, j2 in hunk:
             if tag == 'equal':
                 if prev:
                     prev = (tag, prev[1], i2, prev[3], j2)
                 else:
                     prev = (tag, i1, i2, j1, j2)
             else:
                 if is_ignorable(tag, fromlines[i1:i2], tolines[j1:j2]):
                     ignored_lines = True
                     if prev:
                         prev = 'equal', prev[1], i2, prev[3], j2
                     else:
                         prev = 'equal', i1, i2, j1, j2
                     continue
                 if prev:
                     opcodes.append(prev)
                 opcodes.append((tag, i1, i2, j1, j2))
                 prev = None
     if prev:
         opcodes.append(prev)
 
     if ignored_lines:
         if context is None:
             yield opcodes
         else:
             # we leave at most n lines with the tag 'equal' before and after
             # every change
             n = context
             nn = n + n
 
             group = []
             def all_equal():
                 all(op[0] == 'equal' for op in group)
             for idx, (tag, i1, i2, j1, j2) in enumerate(opcodes):
                 if idx == 0 and tag == 'equal': # Fixup leading unchanged block
                     i1, j1 = max(i1, i2 - n), max(j1, j2 - n)
                 elif tag == 'equal' and i2 - i1 > nn:
                     group.append((tag, i1, min(i2, i1 + n), j1,
                                   min(j2, j1 + n)))
                     if not all_equal():
                         yield group
                     group = []
                     i1, j1 = max(i1, i2 - n), max(j1, j2 - n)
                 group.append((tag, i1, i2, j1, j2))
 
             if group and not (len(group) == 1 and group[0][0] == 'equal'):
                 if group[-1][0] == 'equal': # Fixup trailing unchanged block
                     tag, i1, i2, j1, j2 = group[-1]
                     group[-1] = tag, i1, min(i2, i1 + n), j1, min(j2, j1 + n)
                 if not all_equal():
                     yield group
     else:
         for hunk in hunks:
             yield hunk
 
 
 NO_NEWLINE_AT_END = '\\ No newline at end of file'
 
 
 def unified_diff(fromlines, tolines, context=None, ignore_blank_lines=0,
                  ignore_case=0, ignore_space_changes=0, lineterm='\n'):
     """
     Generator producing lines corresponding to a textual diff.
 
     See `get_filtered_hunks` for the parameter descriptions.
     """
     # TODO: johbo: Check if this can be nicely integrated into the matching
     if ignore_space_changes:
         fromlines = [l.strip() for l in fromlines]
         tolines = [l.strip() for l in tolines]
 
     for group in get_filtered_hunks(fromlines, tolines, context,
                                     ignore_blank_lines, ignore_case,
                                     ignore_space_changes):
         i1, i2, j1, j2 = group[0][1], group[-1][2], group[0][3], group[-1][4]
         if i1 == 0 and i2 == 0:
             i1, i2 = -1, -1  # support for Add changes
         if j1 == 0 and j2 == 0:
             j1, j2 = -1, -1  # support for Delete changes
         yield '@@ -%s +%s @@%s' % (
             _hunk_range(i1 + 1, i2 - i1),
             _hunk_range(j1 + 1, j2 - j1),
             lineterm)
         for tag, i1, i2, j1, j2 in group:
             if tag == 'equal':
                 for line in fromlines[i1:i2]:
                     if not line.endswith(lineterm):
                         yield ' ' + line + lineterm
                         yield NO_NEWLINE_AT_END + lineterm
                     else:
                         yield ' ' + line
             else:
                 if tag in ('replace', 'delete'):
                     for line in fromlines[i1:i2]:
                         if not line.endswith(lineterm):
                             yield '-' + line + lineterm
                             yield NO_NEWLINE_AT_END + lineterm
                         else:
                             yield '-' + line
                 if tag in ('replace', 'insert'):
                     for line in tolines[j1:j2]:
                         if not line.endswith(lineterm):
                             yield '+' + line + lineterm
                             yield NO_NEWLINE_AT_END + lineterm
                         else:
                             yield '+' + line
 
 
 def _hunk_range(start, length):
     if length != 1:
         return '%d,%d' % (start, length)
     else:
         return '%d' % (start, )