Add support for git_graph_descendant_of

docs/repository.rst

@@ -68,6 +68,7 @@ Below there are some general attributes and methods:
 .. automethod:: pygit2.Repository.read
 .. automethod:: pygit2.Repository.write
 .. automethod:: pygit2.Repository.ahead_behind
+.. automethod:: pygit2.Repository.descendant_of
 .. automethod:: pygit2.Repository.create_reference
 .. automethod:: pygit2.Repository.describe
 .. automethod:: pygit2.Repository.path_is_ignored

pygit2/repository.py

@@ -1130,13 +1130,19 @@ def revert_commit(self, revert_commit, our_commit, mainline=0):
 
 
 class Branches(object):
-    def __init__(self, repository, flag=GIT_BRANCH_ALL):
+    def __init__(self, repository, flag=GIT_BRANCH_ALL, commit=None):
         self._repository = repository
         self._flag = flag
+        if commit is not None:
+            if isinstance(commit, Commit):
+                commit = commit.id
+            elif not isinstance(commit, Oid):
+                commit = self._repository.expand_id(commit)
+        self._commit = commit
 
         if flag == GIT_BRANCH_ALL:
-            self.local = Branches(repository, flag=GIT_BRANCH_LOCAL)
-            self.remote = Branches(repository, flag=GIT_BRANCH_REMOTE)
+            self.local = Branches(repository, flag=GIT_BRANCH_LOCAL, commit=commit)
+            self.remote = Branches(repository, flag=GIT_BRANCH_REMOTE, commit=commit)
 
     def __getitem__(self, name):
         branch = None
@@ -1146,7 +1152,7 @@ def __getitem__(self, name):
         if branch is None and self._flag & GIT_BRANCH_REMOTE:
             branch = self._repository.lookup_branch(name, GIT_BRANCH_REMOTE)
 
-        if branch is None:
+        if branch is None or not self._valid(branch):
             raise KeyError('Branch not found: {}'.format(name))
 
         return branch
@@ -1159,14 +1165,23 @@ def get(self, key):
 
     def __iter__(self):
         for branch_name in self._repository.listall_branches(self._flag):
-            yield branch_name
+            if self._commit is None or self.get(branch_name) is not None:
+                yield branch_name
 
     def create(self, name, commit, force=False):
         return self._repository.create_branch(name, commit, force)
 
     def delete(self, name):
         self[name].delete()
 
+    def _valid(self, branch):
+        return (self._commit is None or branch.target == self._commit or
+                self._repository.descendant_of(branch.target, self._commit))
+
+    def with_commit(self, commit):
+        assert self._commit is None
+        return Branches(self._repository, self._flag, commit)
+
     def __contains__(self, name):
         return self.get(name) is not None
 

src/repository.c

@@ -564,6 +564,35 @@ Repository_workdir__set__(Repository *self, PyObject *py_workdir)
     return 0;
 }
 
+PyDoc_STRVAR(Repository_descendant_of__doc__,
+  "descendant_of(oid, oid) -> bool\n"
+  "\n"
+  "Determine if the second commit is a descendant of the first commit.\n"
+  "Note that a commit is not considered a descendant of itself.");
+
+PyObject *
+Repository_descendant_of(Repository *self, PyObject *args)
+{
+    PyObject *value1;
+    PyObject *value2;
+    git_oid oid1;
+    git_oid oid2;
+    int err;
+
+    if (!PyArg_ParseTuple(args, "OO", &value1, &value2))
+        return NULL;
+
+    err = py_oid_to_git_oid_expand(self->repo, value1, &oid1);
+    if (err < 0)
+        return NULL;
+
+    err = py_oid_to_git_oid_expand(self->repo, value2, &oid2);
+    if (err < 0)
+        return NULL;
+
+    return PyBool_FromLong(git_graph_descendant_of(self->repo, &oid1, &oid2));
+}
+
 PyDoc_STRVAR(Repository_merge_base__doc__,
   "merge_base(oid, oid) -> Oid\n"
   "\n"
@@ -1884,6 +1913,7 @@ PyMethodDef Repository_methods[] = {
     METHOD(Repository, create_tag, METH_VARARGS),
     METHOD(Repository, TreeBuilder, METH_VARARGS),
     METHOD(Repository, walk, METH_VARARGS),
+    METHOD(Repository, descendant_of, METH_VARARGS),
     METHOD(Repository, merge_base, METH_VARARGS),
     METHOD(Repository, merge_analysis, METH_O),
     METHOD(Repository, merge, METH_O),

test/test_branch.py

@@ -37,6 +37,8 @@
 LAST_COMMIT = '2be5719152d4f82c7302b1c0932d8e5f0a4a0e98'
 I18N_LAST_COMMIT = '5470a671a80ac3789f1a6a8cefbcf43ce7af0563'
 ORIGIN_MASTER_COMMIT = '784855caf26449a1914d2cf62d12b9374d76ae78'
+EXCLUSIVE_MASTER_COMMIT = '5ebeeebb320790caf276b9fc8b24546d63316533'
+SHARED_COMMIT = '4ec4389a8068641da2d6578db0419484972284c8'
 
 
 class BranchesObjectTestCase(utils.RepoTestCase):
@@ -116,6 +118,24 @@ def test_branch_name(self):
         self.assertEqual(branch.branch_name, 'i18n')
         self.assertEqual(branch.name, 'refs/heads/i18n')
 
+    def test_with_commit(self):
+        branches = self.repo.branches.with_commit(EXCLUSIVE_MASTER_COMMIT)
+        self.assertEqual(sorted(branches), ['master'])
+        self.assertTrue(branches.get('i18n') is None)
+        self.assertEqual(branches['master'].branch_name, 'master')
+
+        branches = self.repo.branches.with_commit(SHARED_COMMIT)
+        self.assertEqual(sorted(branches), ['i18n', 'master'])
+
+        branches = self.repo.branches.with_commit(LAST_COMMIT)
+        self.assertEqual(sorted(branches), ['master'])
+
+        branches = self.repo.branches.with_commit(self.repo[LAST_COMMIT])
+        self.assertEqual(sorted(branches), ['master'])
+
+        branches = self.repo.branches.remote.with_commit(LAST_COMMIT)
+        self.assertEqual(sorted(branches), [])
+
 
 class BranchesObjectEmptyRepoTestCase(utils.EmptyRepoTestCase):
     def setUp(self):

test/test_repository.py

@@ -348,6 +348,20 @@ def test_merge_base(self):
 
         self.assertEqual(None, self.repo.merge_base(indep, commit))
 
+    def test_descendent_of(self):
+        self.assertFalse(self.repo.descendant_of(
+            '5ebeeebb320790caf276b9fc8b24546d63316533',
+            '4ec4389a8068641da2d6578db0419484972284c8'))
+        self.assertFalse(self.repo.descendant_of(
+            '5ebeeebb320790caf276b9fc8b24546d63316533',
+            '5ebeeebb320790caf276b9fc8b24546d63316533'))
+        self.assertTrue(self.repo.descendant_of(
+            '5ebeeebb320790caf276b9fc8b24546d63316533',
+            'acecd5ea2924a4b900e7e149496e1f4b57976e51'))
+        self.assertFalse(self.repo.descendant_of(
+            'acecd5ea2924a4b900e7e149496e1f4b57976e51',
+            '5ebeeebb320790caf276b9fc8b24546d63316533'))
+
     def test_ahead_behind(self):
         ahead, behind = self.repo.ahead_behind('5ebeeebb320790caf276b9fc8b24546d63316533',
                                                '4ec4389a8068641da2d6578db0419484972284c8')