hg: improve implementations of `successors` and `precursors` properties of Mercurial changesets

* On Mercurial versions supporting it, make the properties return the closest changesets in the obsolescence chain that are in the repository.
* On older Mercurial versions, fall back to the previous implementations.

kallithea/lib/vcs/backends/hg/changeset.py

@@ -1,451 +1,455 b''
 import os
 import posixpath
 
 from kallithea.lib.vcs.conf import settings
 from kallithea.lib.vcs.backends.base import BaseChangeset
 from kallithea.lib.vcs.exceptions import (
     ChangesetDoesNotExistError, ChangesetError, ImproperArchiveTypeError,
     NodeDoesNotExistError, VCSError
 )
 from kallithea.lib.vcs.nodes import (
     AddedFileNodesGenerator, ChangedFileNodesGenerator, DirNode, FileNode,
     NodeKind, RemovedFileNodesGenerator, RootNode, SubModuleNode
 )
 from kallithea.lib.vcs.utils import safe_str, safe_unicode, date_fromtimestamp
 from kallithea.lib.vcs.utils.lazy import LazyProperty
 from kallithea.lib.vcs.utils.paths import get_dirs_for_path
 from kallithea.lib.vcs.utils.hgcompat import archival, hex
 
 from mercurial import obsolete
 
 
 class MercurialChangeset(BaseChangeset):
     """
     Represents state of the repository at the single revision.
     """
 
     def __init__(self, repository, revision):
         self.repository = repository
         assert isinstance(revision, basestring), repr(revision)
         self.raw_id = revision
         self._ctx = repository._repo[revision]
         self.revision = self._ctx._rev
         self.nodes = {}
 
     @LazyProperty
     def tags(self):
         return map(safe_unicode, self._ctx.tags())
 
     @LazyProperty
     def branch(self):
         return safe_unicode(self._ctx.branch())
 
     @LazyProperty
     def branches(self):
         return [safe_unicode(self._ctx.branch())]
 
     @LazyProperty
     def closesbranch(self):
         return self._ctx.closesbranch()
 
     @LazyProperty
     def obsolete(self):
         return self._ctx.obsolete()
 
     @LazyProperty
     def bumped(self):
         try:
             return self._ctx.phasedivergent()
         except AttributeError: # renamed in Mercurial 4.6 (9fa874fb34e1)
             return self._ctx.bumped()
 
     @LazyProperty
     def divergent(self):
         try:
             return self._ctx.contentdivergent()
         except AttributeError: # renamed in Mercurial 4.6 (8b2d7684407b)
             return self._ctx.divergent()
 
     @LazyProperty
     def extinct(self):
         return self._ctx.extinct()
 
     @LazyProperty
     def unstable(self):
         try:
             return self._ctx.orphan()
         except AttributeError: # renamed in Mercurial 4.6 (03039ff3082b)
             return self._ctx.unstable()
 
     @LazyProperty
     def phase(self):
         if(self._ctx.phase() == 1):
             return 'Draft'
         elif(self._ctx.phase() == 2):
             return 'Secret'
         else:
             return ''
 
     @LazyProperty
     def successors(self):
         try:
+            # This works starting from Mercurial 4.3: the function `successorssets` was moved to the mercurial.obsutil module and gained the `closest` parameter.
             from mercurial import obsutil
-            successors = obsutil.successorssets(self._ctx._repo, self._ctx.node())
-        except ImportError:  # moved in Mercurial 4.3 (4f49810a1011)
+            successors = obsutil.successorssets(self._ctx._repo, self._ctx.node(), closest=True)
+        except ImportError:
+            # fallback for older versions
             successors = obsolete.successorssets(self._ctx._repo, self._ctx.node())
         if successors:
             # flatten the list here handles both divergent (len > 1)
             # and the usual case (len = 1)
             successors = [hex(n)[:12] for sub in successors for n in sub if n != self._ctx.node()]
 
         return successors
 
     @LazyProperty
     def predecessors(self):
-        predecessors = set()
-        nm = self._ctx._repo.changelog.nodemap
         try:
-            raw_predecessors = self._ctx._repo.obsstore.predecessors
-        except AttributeError:  # renamed in Mercurial 4.4 (d5acd967f95a)
-            raw_predecessors = self._ctx._repo.obsstore.precursors
-        for p in raw_predecessors.get(self._ctx.node(), ()):
-            pr = nm.get(p[0])
-            if pr is not None:
-                predecessors.add(hex(p[0])[:12])
-        return predecessors
+            # This works starting from Mercurial 4.3: the function `closestpredecessors` was added.
+            from mercurial import obsutil
+            return [hex(n)[:12] for n in obsutil.closestpredecessors(self._ctx._repo, self._ctx.node())]
+        except ImportError:
+            # fallback for older versions
+            predecessors = set()
+            nm = self._ctx._repo.changelog.nodemap
+            for p in self._ctx._repo.obsstore.precursors.get(self._ctx.node(), ()):
+                pr = nm.get(p[0])
+                if pr is not None:
+                    predecessors.add(hex(p[0])[:12])
+            return predecessors
 
     @LazyProperty
     def bookmarks(self):
         return map(safe_unicode, self._ctx.bookmarks())
 
     @LazyProperty
     def message(self):
         return safe_unicode(self._ctx.description())
 
     @LazyProperty
     def committer(self):
         return safe_unicode(self.author)
 
     @LazyProperty
     def author(self):
         return safe_unicode(self._ctx.user())
 
     @LazyProperty
     def date(self):
         return date_fromtimestamp(*self._ctx.date())
 
     @LazyProperty
     def _timestamp(self):
         return self._ctx.date()[0]
 
     @LazyProperty
     def status(self):
         """
         Returns modified, added, removed, deleted files for current changeset
         """
         return self.repository._repo.status(self._ctx.p1().node(),
                                             self._ctx.node())
 
     @LazyProperty
     def _file_paths(self):
         return list(self._ctx)
 
     @LazyProperty
     def _dir_paths(self):
         p = list(set(get_dirs_for_path(*self._file_paths)))
         p.insert(0, '')
         return p
 
     @LazyProperty
     def _paths(self):
         return self._dir_paths + self._file_paths
 
     @LazyProperty
     def id(self):
         if self.last:
             return u'tip'
         return self.short_id
 
     @LazyProperty
     def short_id(self):
         return self.raw_id[:12]
 
     @LazyProperty
     def parents(self):
         """
         Returns list of parents changesets.
         """
         return [self.repository.get_changeset(parent.rev())
                 for parent in self._ctx.parents() if parent.rev() >= 0]
 
     @LazyProperty
     def children(self):
         """
         Returns list of children changesets.
         """
         return [self.repository.get_changeset(child.rev())
                 for child in self._ctx.children() if child.rev() >= 0]
 
     def next(self, branch=None):
         if branch and self.branch != branch:
             raise VCSError('Branch option used on changeset not belonging '
                            'to that branch')
 
         cs = self
         while True:
             try:
                 next_ = cs.repository.revisions.index(cs.raw_id) + 1
                 next_rev = cs.repository.revisions[next_]
             except IndexError:
                 raise ChangesetDoesNotExistError
             cs = cs.repository.get_changeset(next_rev)
 
             if not branch or branch == cs.branch:
                 return cs
 
     def prev(self, branch=None):
         if branch and self.branch != branch:
             raise VCSError('Branch option used on changeset not belonging '
                            'to that branch')
 
         cs = self
         while True:
             try:
                 prev_ = cs.repository.revisions.index(cs.raw_id) - 1
                 if prev_ < 0:
                     raise IndexError
                 prev_rev = cs.repository.revisions[prev_]
             except IndexError:
                 raise ChangesetDoesNotExistError
             cs = cs.repository.get_changeset(prev_rev)
 
             if not branch or branch == cs.branch:
                 return cs
 
     def diff(self):
         # Only used for feed diffstat
         return ''.join(self._ctx.diff())
 
     def _fix_path(self, path):
         """
         Paths are stored without trailing slash so we need to get rid off it if
         needed. Also mercurial keeps filenodes as str so we need to decode
         from unicode to str
         """
         if path.endswith('/'):
             path = path.rstrip('/')
 
         return safe_str(path)
 
     def _get_kind(self, path):
         path = self._fix_path(path)
         if path in self._file_paths:
             return NodeKind.FILE
         elif path in self._dir_paths:
             return NodeKind.DIR
         else:
             raise ChangesetError("Node does not exist at the given path '%s'"
                 % (path))
 
     def _get_filectx(self, path):
         path = self._fix_path(path)
         if self._get_kind(path) != NodeKind.FILE:
             raise ChangesetError("File does not exist for revision %s at "
                 " '%s'" % (self.raw_id, path))
         return self._ctx.filectx(path)
 
     def _extract_submodules(self):
         """
         returns a dictionary with submodule information from substate file
         of hg repository
         """
         return self._ctx.substate
 
     def get_file_mode(self, path):
         """
         Returns stat mode of the file at the given ``path``.
         """
         fctx = self._get_filectx(path)
         if 'x' in fctx.flags():
             return 0100755
         else:
             return 0100644
 
     def get_file_content(self, path):
         """
         Returns content of the file at given ``path``.
         """
         fctx = self._get_filectx(path)
         return fctx.data()
 
     def get_file_size(self, path):
         """
         Returns size of the file at given ``path``.
         """
         fctx = self._get_filectx(path)
         return fctx.size()
 
     def get_file_changeset(self, path):
         """
         Returns last commit of the file at the given ``path``.
         """
         return self.get_file_history(path, limit=1)[0]
 
     def get_file_history(self, path, limit=None):
         """
         Returns history of file as reversed list of ``Changeset`` objects for
         which file at given ``path`` has been modified.
         """
         fctx = self._get_filectx(path)
         hist = []
         cnt = 0
         for cs in reversed([x for x in fctx.filelog()]):
             cnt += 1
             hist.append(hex(fctx.filectx(cs).node()))
             if limit is not None and cnt == limit:
                 break
 
         return [self.repository.get_changeset(node) for node in hist]
 
     def get_file_annotate(self, path):
         """
         Returns a generator of four element tuples with
             lineno, sha, changeset lazy loader and line
         """
         annotations = self._get_filectx(path).annotate()
         try:
             annotation_lines = [(annotateline.fctx, annotateline.text) for annotateline in annotations]
         except AttributeError: # annotateline was introduced in Mercurial 4.6 (b33b91ca2ec2)
             try:
                 annotation_lines = [(aline.fctx, l) for aline, l in annotations]
             except AttributeError: # aline.fctx was introduced in Mercurial 4.4
                 annotation_lines = [(aline[0], l) for aline, l in annotations]
         for i, (fctx, l) in enumerate(annotation_lines):
             sha = fctx.hex()
             yield (i + 1, sha, lambda sha=sha, l=l: self.repository.get_changeset(sha), l)
 
     def fill_archive(self, stream=None, kind='tgz', prefix=None,
                      subrepos=False):
         """
         Fills up given stream.
 
         :param stream: file like object.
         :param kind: one of following: ``zip``, ``tgz`` or ``tbz2``.
             Default: ``tgz``.
         :param prefix: name of root directory in archive.
             Default is repository name and changeset's raw_id joined with dash
             (``repo-tip.<KIND>``).
         :param subrepos: include subrepos in this archive.
 
         :raise ImproperArchiveTypeError: If given kind is wrong.
         :raise VcsError: If given stream is None
         """
 
         allowed_kinds = settings.ARCHIVE_SPECS.keys()
         if kind not in allowed_kinds:
             raise ImproperArchiveTypeError('Archive kind not supported use one'
                 'of %s', allowed_kinds)
 
         if stream is None:
             raise VCSError('You need to pass in a valid stream for filling'
                            ' with archival data')
 
         if prefix is None:
             prefix = '%s-%s' % (self.repository.name, self.short_id)
         elif prefix.startswith('/'):
             raise VCSError("Prefix cannot start with leading slash")
         elif prefix.strip() == '':
             raise VCSError("Prefix cannot be empty")
 
         archival.archive(self.repository._repo, stream, self.raw_id,
                          kind, prefix=prefix, subrepos=subrepos)
 
     def get_nodes(self, path):
         """
         Returns combined ``DirNode`` and ``FileNode`` objects list representing
         state of changeset at the given ``path``. If node at the given ``path``
         is not instance of ``DirNode``, ChangesetError would be raised.
         """
 
         if self._get_kind(path) != NodeKind.DIR:
             raise ChangesetError("Directory does not exist for revision %s at "
                 " '%s'" % (self.revision, path))
         path = self._fix_path(path)
 
         filenodes = [FileNode(f, changeset=self) for f in self._file_paths
             if os.path.dirname(f) == path]
         dirs = path == '' and '' or [d for d in self._dir_paths
             if d and posixpath.dirname(d) == path]
         dirnodes = [DirNode(d, changeset=self) for d in dirs
             if os.path.dirname(d) == path]
 
         als = self.repository.alias
         for k, vals in self._extract_submodules().iteritems():
             #vals = url,rev,type
             loc = vals[0]
             cs = vals[1]
             dirnodes.append(SubModuleNode(k, url=loc, changeset=cs,
                                           alias=als))
         nodes = dirnodes + filenodes
         # cache nodes
         for node in nodes:
             self.nodes[node.path] = node
         nodes.sort()
 
         return nodes
 
     def get_node(self, path):
         """
         Returns ``Node`` object from the given ``path``. If there is no node at
         the given ``path``, ``ChangesetError`` would be raised.
         """
 
         path = self._fix_path(path)
 
         if path not in self.nodes:
             if path in self._file_paths:
                 node = FileNode(path, changeset=self)
             elif path in self._dir_paths or path in self._dir_paths:
                 if path == '':
                     node = RootNode(changeset=self)
                 else:
                     node = DirNode(path, changeset=self)
             else:
                 raise NodeDoesNotExistError("There is no file nor directory "
                     "at the given path: '%s' at revision %s"
                     % (path, self.short_id))
             # cache node
             self.nodes[path] = node
         return self.nodes[path]
 
     @LazyProperty
     def affected_files(self):
         """
         Gets a fast accessible file changes for given changeset
         """
         return self._ctx.files()
 
     @property
     def added(self):
         """
         Returns list of added ``FileNode`` objects.
         """
         return AddedFileNodesGenerator([n for n in self.status[1]], self)
 
     @property
     def changed(self):
         """
         Returns list of modified ``FileNode`` objects.
         """
         return ChangedFileNodesGenerator([n for n in self.status[0]], self)
 
     @property
     def removed(self):
         """
         Returns list of removed ``FileNode`` objects.
         """
         return RemovedFileNodesGenerator([n for n in self.status[2]], self)
 
     @LazyProperty
     def extra(self):
         return self._ctx.extra()

kallithea/tests/vcs/test_hg.py

@@ -1,594 +1,594 b''
 import os
 
 import pytest
 import mock
 
 from kallithea.lib.utils2 import safe_str
 from kallithea.lib.vcs.backends.hg import MercurialRepository, MercurialChangeset
 from kallithea.lib.vcs.exceptions import RepositoryError, VCSError, NodeDoesNotExistError
 from kallithea.lib.vcs.nodes import NodeKind, NodeState
 
 from kallithea.tests.vcs.conf import TEST_HG_REPO, TEST_HG_REPO_CLONE, \
     TEST_HG_REPO_PULL, TESTS_TMP_PATH
 
 
 class TestMercurialRepository(object):
 
     def __check_for_existing_repo(self):
         if os.path.exists(TEST_HG_REPO_CLONE):
             pytest.fail('Cannot test mercurial clone repo as location %s already '
                       'exists. You should manually remove it first.'
                       % TEST_HG_REPO_CLONE)
 
     def setup_method(self):
         self.repo = MercurialRepository(safe_str(TEST_HG_REPO))
 
     def test_wrong_repo_path(self):
         wrong_repo_path = os.path.join(TESTS_TMP_PATH, 'errorrepo')
         with pytest.raises(RepositoryError):
             MercurialRepository(wrong_repo_path)
 
     def test_unicode_path_repo(self):
         with pytest.raises(VCSError):
             MercurialRepository(u'iShouldFail')
 
     def test_repo_clone(self):
         self.__check_for_existing_repo()
         repo = MercurialRepository(safe_str(TEST_HG_REPO))
         repo_clone = MercurialRepository(TEST_HG_REPO_CLONE,
             src_url=TEST_HG_REPO, update_after_clone=True)
         assert len(repo.revisions) == len(repo_clone.revisions)
         # Checking hashes of changesets should be enough
         for changeset in repo.get_changesets():
             raw_id = changeset.raw_id
             assert raw_id == repo_clone.get_changeset(raw_id).raw_id
 
     def test_repo_clone_with_update(self):
         repo = MercurialRepository(safe_str(TEST_HG_REPO))
         repo_clone = MercurialRepository(TEST_HG_REPO_CLONE + '_w_update',
             src_url=TEST_HG_REPO, update_after_clone=True)
         assert len(repo.revisions) == len(repo_clone.revisions)
 
         # check if current workdir was updated
         assert os.path.isfile(
             os.path.join(
                 TEST_HG_REPO_CLONE + '_w_update', 'MANIFEST.in'
             )
         )
 
     def test_repo_clone_without_update(self):
         repo = MercurialRepository(safe_str(TEST_HG_REPO))
         repo_clone = MercurialRepository(TEST_HG_REPO_CLONE + '_wo_update',
             src_url=TEST_HG_REPO, update_after_clone=False)
         assert len(repo.revisions) == len(repo_clone.revisions)
         assert not os.path.isfile(
             os.path.join(
                 TEST_HG_REPO_CLONE + '_wo_update', 'MANIFEST.in'
             )
         )
 
     def test_pull(self):
         if os.path.exists(TEST_HG_REPO_PULL):
             pytest.fail('Cannot test mercurial pull command as location %s '
                       'already exists. You should manually remove it first'
                       % TEST_HG_REPO_PULL)
         repo_new = MercurialRepository(TEST_HG_REPO_PULL, create=True)
         assert len(self.repo.revisions) > len(repo_new.revisions)
 
         repo_new.pull(self.repo.path)
         repo_new = MercurialRepository(TEST_HG_REPO_PULL)
         assert len(self.repo.revisions) == len(repo_new.revisions)
 
     def test_revisions(self):
         # there are 21 revisions at bitbucket now
         # so we can assume they would be available from now on
         subset = set(['b986218ba1c9b0d6a259fac9b050b1724ed8e545',
                  '3d8f361e72ab303da48d799ff1ac40d5ac37c67e',
                  '6cba7170863a2411822803fa77a0a264f1310b35',
                  '56349e29c2af3ac913b28bde9a2c6154436e615b',
                  '2dda4e345facb0ccff1a191052dd1606dba6781d',
                  '6fff84722075f1607a30f436523403845f84cd9e',
                  '7d4bc8ec6be56c0f10425afb40b6fc315a4c25e7',
                  '3803844fdbd3b711175fc3da9bdacfcd6d29a6fb',
                  'dc5d2c0661b61928834a785d3e64a3f80d3aad9c',
                  'be90031137367893f1c406e0a8683010fd115b79',
                  'db8e58be770518cbb2b1cdfa69146e47cd481481',
                  '84478366594b424af694a6c784cb991a16b87c21',
                  '17f8e105dddb9f339600389c6dc7175d395a535c',
                  '20a662e756499bde3095ffc9bc0643d1def2d0eb',
                  '2e319b85e70a707bba0beff866d9f9de032aa4f9',
                  '786facd2c61deb9cf91e9534735124fb8fc11842',
                  '94593d2128d38210a2fcd1aabff6dda0d6d9edf8',
                  'aa6a0de05b7612707db567078e130a6cd114a9a7',
                  'eada5a770da98ab0dd7325e29d00e0714f228d09'
                 ])
         assert subset.issubset(set(self.repo.revisions))
 
         # check if we have the proper order of revisions
         org = ['b986218ba1c9b0d6a259fac9b050b1724ed8e545',
                 '3d8f361e72ab303da48d799ff1ac40d5ac37c67e',
                 '6cba7170863a2411822803fa77a0a264f1310b35',
                 '56349e29c2af3ac913b28bde9a2c6154436e615b',
                 '2dda4e345facb0ccff1a191052dd1606dba6781d',
                 '6fff84722075f1607a30f436523403845f84cd9e',
                 '7d4bc8ec6be56c0f10425afb40b6fc315a4c25e7',
                 '3803844fdbd3b711175fc3da9bdacfcd6d29a6fb',
                 'dc5d2c0661b61928834a785d3e64a3f80d3aad9c',
                 'be90031137367893f1c406e0a8683010fd115b79',
                 'db8e58be770518cbb2b1cdfa69146e47cd481481',
                 '84478366594b424af694a6c784cb991a16b87c21',
                 '17f8e105dddb9f339600389c6dc7175d395a535c',
                 '20a662e756499bde3095ffc9bc0643d1def2d0eb',
                 '2e319b85e70a707bba0beff866d9f9de032aa4f9',
                 '786facd2c61deb9cf91e9534735124fb8fc11842',
                 '94593d2128d38210a2fcd1aabff6dda0d6d9edf8',
                 'aa6a0de05b7612707db567078e130a6cd114a9a7',
                 'eada5a770da98ab0dd7325e29d00e0714f228d09',
                 '2c1885c735575ca478bf9e17b0029dca68824458',
                 'd9bcd465040bf869799b09ad732c04e0eea99fe9',
                 '469e9c847fe1f6f7a697b8b25b4bc5b48780c1a7',
                 '4fb8326d78e5120da2c7468dcf7098997be385da',
                 '62b4a097164940bd66030c4db51687f3ec035eed',
                 '536c1a19428381cfea92ac44985304f6a8049569',
                 '965e8ab3c44b070cdaa5bf727ddef0ada980ecc4',
                 '9bb326a04ae5d98d437dece54be04f830cf1edd9',
                 'f8940bcb890a98c4702319fbe36db75ea309b475',
                 'ff5ab059786ebc7411e559a2cc309dfae3625a3b',
                 '6b6ad5f82ad5bb6190037671bd254bd4e1f4bf08',
                 'ee87846a61c12153b51543bf860e1026c6d3dcba', ]
         assert org == self.repo.revisions[:31]
 
     def test_iter_slice(self):
         sliced = list(self.repo[:10])
         itered = list(self.repo)[:10]
         assert sliced == itered
 
     def test_slicing(self):
         # 4 1 5 10 95
         for sfrom, sto, size in [(0, 4, 4), (1, 2, 1), (10, 15, 5),
                                  (10, 20, 10), (5, 100, 95)]:
             revs = list(self.repo[sfrom:sto])
             assert len(revs) == size
             assert revs[0] == self.repo.get_changeset(sfrom)
             assert revs[-1] == self.repo.get_changeset(sto - 1)
 
     def test_branches(self):
         # TODO: Need more tests here
 
         # active branches
         assert 'default' in self.repo.branches
         assert 'stable' in self.repo.branches
 
         # closed
         assert 'git' in self.repo._get_branches(closed=True)
         assert 'web' in self.repo._get_branches(closed=True)
 
         for name, id in self.repo.branches.items():
             assert isinstance(self.repo.get_changeset(id), MercurialChangeset)
 
     def test_tip_in_tags(self):
         # tip is always a tag
         assert 'tip' in self.repo.tags
 
     def test_tip_changeset_in_tags(self):
         tip = self.repo.get_changeset()
         assert self.repo.tags['tip'] == tip.raw_id
 
     def test_initial_changeset(self):
 
         init_chset = self.repo.get_changeset(0)
         assert init_chset.message == 'initial import'
         assert init_chset.author == 'Marcin Kuzminski <[e-mail]>'
         assert sorted(init_chset._file_paths) == sorted([
             'vcs/__init__.py',
             'vcs/backends/BaseRepository.py',
             'vcs/backends/__init__.py',
         ])
 
         assert sorted(init_chset._dir_paths) == sorted(['', 'vcs', 'vcs/backends'])
 
         with pytest.raises(NodeDoesNotExistError):
             init_chset.get_node(path='foobar')
 
         node = init_chset.get_node('vcs/')
         assert hasattr(node, 'kind')
         assert node.kind == NodeKind.DIR
 
         node = init_chset.get_node('vcs')
         assert hasattr(node, 'kind')
         assert node.kind == NodeKind.DIR
 
         node = init_chset.get_node('vcs/__init__.py')
         assert hasattr(node, 'kind')
         assert node.kind == NodeKind.FILE
 
     def test_not_existing_changeset(self):
         # rawid
         with pytest.raises(RepositoryError):
             self.repo.get_changeset('abcd' * 10)
         # shortid
         with pytest.raises(RepositoryError):
             self.repo.get_changeset('erro' * 4)
         # numeric
         with pytest.raises(RepositoryError):
             self.repo.get_changeset(self.repo.count() + 1)
 
         # Small chance we ever get to this one
         revision = pow(2, 30)
         with pytest.raises(RepositoryError):
             self.repo.get_changeset(revision)
 
     def test_changeset10(self):
 
         chset10 = self.repo.get_changeset(10)
         readme = """===
 VCS
 ===
 
 Various Version Control System management abstraction layer for Python.
 
 Introduction
 ------------
 
 TODO: To be written...
 
 """
         node = chset10.get_node('README.rst')
         assert node.kind == NodeKind.FILE
         assert node.content == readme
 
     @mock.patch('kallithea.lib.vcs.backends.hg.repository.diffopts')
     def test_get_diff_does_not_sanitize_zero_context(self, mock_diffopts):
         zero_context = 0
 
         self.repo.get_diff(0, 1, 'foo', context=zero_context)
 
         mock_diffopts.assert_called_once_with(git=True, showfunc=True, ignorews=False, context=zero_context)
 
     @mock.patch('kallithea.lib.vcs.backends.hg.repository.diffopts')
     def test_get_diff_sanitizes_negative_context(self, mock_diffopts):
         negative_context = -10
         zero_context = 0
 
         self.repo.get_diff(0, 1, 'foo', context=negative_context)
 
         mock_diffopts.assert_called_once_with(git=True, showfunc=True, ignorews=False, context=zero_context)
 
 
 class TestMercurialChangeset(object):
 
     def setup_method(self):
         self.repo = MercurialRepository(safe_str(TEST_HG_REPO))
 
     def _test_equality(self, changeset):
         revision = changeset.revision
         assert changeset == self.repo.get_changeset(revision)
 
     def test_equality(self):
         revs = [0, 10, 20]
         changesets = [self.repo.get_changeset(rev) for rev in revs]
         for changeset in changesets:
             self._test_equality(changeset)
 
     def test_default_changeset(self):
         tip = self.repo.get_changeset('tip')
         assert tip == self.repo.get_changeset()
         assert tip == self.repo.get_changeset(revision=None)
         assert tip == list(self.repo[-1:])[0]
 
     def test_root_node(self):
         tip = self.repo.get_changeset('tip')
         assert tip.root is tip.get_node('')
 
     def test_lazy_fetch(self):
         """
         Test if changeset's nodes expands and are cached as we walk through
         the revision. This test is somewhat hard to write as order of tests
         is a key here. Written by running command after command in a shell.
         """
         chset = self.repo.get_changeset(45)
         assert len(chset.nodes) == 0
         root = chset.root
         assert len(chset.nodes) == 1
         assert len(root.nodes) == 8
         # accessing root.nodes updates chset.nodes
         assert len(chset.nodes) == 9
 
         docs = root.get_node('docs')
         # we haven't yet accessed anything new as docs dir was already cached
         assert len(chset.nodes) == 9
         assert len(docs.nodes) == 8
         # accessing docs.nodes updates chset.nodes
         assert len(chset.nodes) == 17
 
         assert docs is chset.get_node('docs')
         assert docs is root.nodes[0]
         assert docs is root.dirs[0]
         assert docs is chset.get_node('docs')
 
     def test_nodes_with_changeset(self):
         chset = self.repo.get_changeset(45)
         root = chset.root
         docs = root.get_node('docs')
         assert docs is chset.get_node('docs')
         api = docs.get_node('api')
         assert api is chset.get_node('docs/api')
         index = api.get_node('index.rst')
         assert index is chset.get_node('docs/api/index.rst')
         assert index is chset.get_node('docs').get_node('api').get_node('index.rst')
 
     def test_branch_and_tags(self):
         chset0 = self.repo.get_changeset(0)
         assert chset0.branch == 'default'
         assert chset0.branches == ['default']
         assert chset0.tags == []
 
         chset10 = self.repo.get_changeset(10)
         assert chset10.branch == 'default'
         assert chset10.branches == ['default']
         assert chset10.tags == []
 
         chset44 = self.repo.get_changeset(44)
         assert chset44.branch == 'web'
         assert chset44.branches == ['web']
 
         tip = self.repo.get_changeset('tip')
         assert 'tip' in tip.tags
 
     def _test_file_size(self, revision, path, size):
         node = self.repo.get_changeset(revision).get_node(path)
         assert node.is_file()
         assert node.size == size
 
     def test_file_size(self):
         to_check = (
             (10, 'setup.py', 1068),
             (20, 'setup.py', 1106),
             (60, 'setup.py', 1074),
 
             (10, 'vcs/backends/base.py', 2921),
             (20, 'vcs/backends/base.py', 3936),
             (60, 'vcs/backends/base.py', 6189),
         )
         for revision, path, size in to_check:
             self._test_file_size(revision, path, size)
 
     def _test_dir_size(self, revision, path, size):
         node = self.repo.get_changeset(revision).get_node(path)
         assert not node.is_file()
         assert node.size == size
 
     def test_dir_size(self):
         to_check = (
             ('96507bd11ecc', '/', 682421),
             ('a53d9201d4bc', '/', 682410),
             ('90243de06161', '/', 682006),
         )
         for revision, path, size in to_check:
             self._test_dir_size(revision, path, size)
 
     def test_repo_size(self):
         assert self.repo.size == 682421
 
     def test_file_history(self):
         # we can only check if those revisions are present in the history
         # as we cannot update this test every time file is changed
         files = {
             'setup.py': [7, 18, 45, 46, 47, 69, 77],
             'vcs/nodes.py': [7, 8, 24, 26, 30, 45, 47, 49, 56, 57, 58, 59, 60,
                 61, 73, 76],
             'vcs/backends/hg.py': [4, 5, 6, 11, 12, 13, 14, 15, 16, 21, 22, 23,
                 26, 27, 28, 30, 31, 33, 35, 36, 37, 38, 39, 40, 41, 44, 45, 47,
                 48, 49, 53, 54, 55, 58, 60, 61, 67, 68, 69, 70, 73, 77, 78, 79,
                 82],
         }
         for path, revs in files.items():
             tip = self.repo.get_changeset(revs[-1])
             node = tip.get_node(path)
             node_revs = [chset.revision for chset in node.history]
             assert set(revs).issubset(set(node_revs)), \
                 "We assumed that %s is subset of revisions for which file %s " \
                 "has been changed, and history of that node returned: %s" \
                 % (revs, path, node_revs)
 
     def test_file_annotate(self):
         files = {
                  'vcs/backends/__init__.py':
                   {89: {'lines_no': 31,
                         'changesets': [32, 32, 61, 32, 32, 37, 32, 32, 32, 44,
                                        37, 37, 37, 37, 45, 37, 44, 37, 37, 37,
                                        32, 32, 32, 32, 37, 32, 37, 37, 32,
                                        32, 32]},
                    20: {'lines_no': 1,
                         'changesets': [4]},
                    55: {'lines_no': 31,
                         'changesets': [32, 32, 45, 32, 32, 37, 32, 32, 32, 44,
                                        37, 37, 37, 37, 45, 37, 44, 37, 37, 37,
                                        32, 32, 32, 32, 37, 32, 37, 37, 32,
                                        32, 32]}},
                  'vcs/exceptions.py':
                  {89: {'lines_no': 18,
                        'changesets': [16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
                                       16, 16, 17, 16, 16, 18, 18, 18]},
                   20: {'lines_no': 18,
                        'changesets': [16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
                                       16, 16, 17, 16, 16, 18, 18, 18]},
                   55: {'lines_no': 18, 'changesets': [16, 16, 16, 16, 16, 16,
                                                       16, 16, 16, 16, 16, 16,
                                                       17, 16, 16, 18, 18, 18]}},
                  'MANIFEST.in': {89: {'lines_no': 5,
                                       'changesets': [7, 7, 7, 71, 71]},
                                  20: {'lines_no': 3,
                                       'changesets': [7, 7, 7]},
                                  55: {'lines_no': 3,
                                      'changesets': [7, 7, 7]}}}
 
         for fname, revision_dict in files.items():
             for rev, data in revision_dict.items():
                 cs = self.repo.get_changeset(rev)
                 l1_1 = [x[1] for x in cs.get_file_annotate(fname)]
                 l1_2 = [x[2]().raw_id for x in cs.get_file_annotate(fname)]
                 assert l1_1 == l1_2
                 l1 = l1_2 = [x[2]().revision for x in cs.get_file_annotate(fname)]
                 l2 = files[fname][rev]['changesets']
                 assert l1 == l2, "The lists of revision for %s@rev%s" \
                     "from annotation list should match each other," \
                     "got \n%s \nvs \n%s " % (fname, rev, l1, l2)
 
     def test_changeset_state(self):
         """
         Tests which files have been added/changed/removed at particular revision
         """
 
         # rev 46ad32a4f974:
         # hg st --rev 46ad32a4f974
         #    changed: 13
         #    added:   20
         #    removed: 1
         changed = set(['.hgignore'
             , 'README.rst' , 'docs/conf.py' , 'docs/index.rst' , 'setup.py'
             , 'tests/test_hg.py' , 'tests/test_nodes.py' , 'vcs/__init__.py'
             , 'vcs/backends/__init__.py' , 'vcs/backends/base.py'
             , 'vcs/backends/hg.py' , 'vcs/nodes.py' , 'vcs/utils/__init__.py'])
 
         added = set(['docs/api/backends/hg.rst'
             , 'docs/api/backends/index.rst' , 'docs/api/index.rst'
             , 'docs/api/nodes.rst' , 'docs/api/web/index.rst'
             , 'docs/api/web/simplevcs.rst' , 'docs/installation.rst'
             , 'docs/quickstart.rst' , 'setup.cfg' , 'vcs/utils/baseui_config.py'
             , 'vcs/utils/web.py' , 'vcs/web/__init__.py' , 'vcs/web/exceptions.py'
             , 'vcs/web/simplevcs/__init__.py' , 'vcs/web/simplevcs/exceptions.py'
             , 'vcs/web/simplevcs/middleware.py' , 'vcs/web/simplevcs/models.py'
             , 'vcs/web/simplevcs/settings.py' , 'vcs/web/simplevcs/utils.py'
             , 'vcs/web/simplevcs/views.py'])
 
         removed = set(['docs/api.rst'])
 
         chset64 = self.repo.get_changeset('46ad32a4f974')
         assert set((node.path for node in chset64.added)) == added
         assert set((node.path for node in chset64.changed)) == changed
         assert set((node.path for node in chset64.removed)) == removed
 
         # rev b090f22d27d6:
         # hg st --rev b090f22d27d6
         #    changed: 13
         #    added:   20
         #    removed: 1
         chset88 = self.repo.get_changeset('b090f22d27d6')
         assert set((node.path for node in chset88.added)) == set()
         assert set((node.path for node in chset88.changed)) == set(['.hgignore'])
         assert set((node.path for node in chset88.removed)) == set()
 
         # 85:
         #    added:   2 ['vcs/utils/diffs.py', 'vcs/web/simplevcs/views/diffs.py']
         #    changed: 4 ['vcs/web/simplevcs/models.py', ...]
         #    removed: 1 ['vcs/utils/web.py']
         chset85 = self.repo.get_changeset(85)
         assert set((node.path for node in chset85.added)) == set([
             'vcs/utils/diffs.py',
             'vcs/web/simplevcs/views/diffs.py'
         ])
 
         assert set((node.path for node in chset85.changed)) == set([
             'vcs/web/simplevcs/models.py',
             'vcs/web/simplevcs/utils.py',
             'vcs/web/simplevcs/views/__init__.py',
             'vcs/web/simplevcs/views/repository.py',
         ])
 
         assert set((node.path for node in chset85.removed)) == set([
             'vcs/utils/web.py'
         ])
 
 
     def test_files_state(self):
         """
         Tests state of FileNodes.
         """
         chset = self.repo.get_changeset(85)
         node = chset.get_node('vcs/utils/diffs.py')
         assert node.state, NodeState.ADDED
         assert node.added
         assert not node.changed
         assert not node.not_changed
         assert not node.removed
 
         chset = self.repo.get_changeset(88)
         node = chset.get_node('.hgignore')
         assert node.state, NodeState.CHANGED
         assert not node.added
         assert node.changed
         assert not node.not_changed
         assert not node.removed
 
         chset = self.repo.get_changeset(85)
         node = chset.get_node('setup.py')
         assert node.state, NodeState.NOT_CHANGED
         assert not node.added
         assert not node.changed
         assert node.not_changed
         assert not node.removed
 
         # If node has REMOVED state then trying to fetch it would raise
         # ChangesetError exception
         chset = self.repo.get_changeset(2)
         path = 'vcs/backends/BaseRepository.py'
         with pytest.raises(NodeDoesNotExistError):
             chset.get_node(path)
         # but it would be one of ``removed`` (changeset's attribute)
         assert path in [rf.path for rf in chset.removed]
 
     def test_commit_message_is_unicode(self):
         for cm in self.repo:
             assert type(cm.message) == unicode
 
     def test_changeset_author_is_unicode(self):
         for cm in self.repo:
             assert type(cm.author) == unicode
 
     def test_repo_files_content_is_unicode(self):
         test_changeset = self.repo.get_changeset(100)
         for node in test_changeset.get_node('/'):
             if node.is_file():
                 assert type(node.content) == unicode
 
     def test_wrong_path(self):
         # There is 'setup.py' in the root dir but not there:
         path = 'foo/bar/setup.py'
         with pytest.raises(VCSError):
             self.repo.get_changeset().get_node(path)
 
     def test_archival_file(self):
         # TODO:
         pass
 
     def test_archival_as_generator(self):
         # TODO:
         pass
 
     def test_archival_wrong_kind(self):
         tip = self.repo.get_changeset()
         with pytest.raises(VCSError):
             tip.fill_archive(kind='error')
 
     def test_archival_empty_prefix(self):
         # TODO:
         pass
 
     def test_author_email(self):
         assert '[e-mail]' == self.repo.get_changeset('b986218ba1c9').author_email
         assert '[e-mail]' == self.repo.get_changeset('3803844fdbd3').author_email
         assert '' == self.repo.get_changeset('84478366594b').author_email
 
     def test_author_username(self):
         assert 'Marcin Kuzminski' == self.repo.get_changeset('b986218ba1c9').author_name
         assert 'Lukasz Balcerzak' == self.repo.get_changeset('3803844fdbd3').author_name
         assert 'marcink' == self.repo.get_changeset('84478366594b').author_name
 
     def test_successors(self):
         init_chset = self.repo.get_changeset(0)
         assert init_chset.successors == []
 
     def test_predecessors(self):
         init_chset = self.repo.get_changeset(0)
-        assert init_chset.predecessors == set([])
+        assert len(init_chset.predecessors) == 0