Get rid of a settable Reference.target

Updating the target of a reference is not like setting a property. It
involves appending to the reflog under the same lock, so we must do it
all the same time. Thus setting the target becomes a function which
takes the new target and what the use would like to add to the reflog.

src/reference.c

@@ -205,10 +205,7 @@ Reference_resolve(Reference *self, PyObject *args)
 PyDoc_STRVAR(Reference_target__doc__,
     "The reference target: If direct the value will be an Oid object, if it\n"
     "is symbolic it will be an string with the full name of the target\n"
-    "reference.\n"
-    "\n"
-    "The target is writable. Setting the Reference's target to another Oid\n"
-    "object will direct the reference to that Oid instead.");
+    "reference.\n");
 
 PyObject *
 Reference_target__get__(Reference *self)
@@ -230,17 +227,6 @@ Reference_target__get__(Reference *self)
     return to_path(c_name);
 }
 
-int
-Reference_target__set__(Reference *self, PyObject *py_target)
-{
-    CHECK_REFERENCE_INT(self);
-
-    if (!PyObject_CallMethod(self, "set_target", "O", py_target))
-        return -1;
-
-    return 0;
-}
-
 PyDoc_STRVAR(Reference_set_target__doc__,
     "set_target(target, [signature, message])\n"
     "\n"
@@ -499,7 +485,7 @@ PyMethodDef Reference_methods[] = {
 PyGetSetDef Reference_getseters[] = {
     GETTER(Reference, name),
     GETTER(Reference, shorthand),
-    GETSET(Reference, target),
+    GETTER(Reference, target),
     GETTER(Reference, type),
     {NULL}
 };

test/test_refs.py

@@ -31,7 +31,7 @@ from __future__ import absolute_import
 from __future__ import unicode_literals
 import unittest
 
-from pygit2 import GitError, GIT_REF_OID, GIT_REF_SYMBOLIC
+from pygit2 import GitError, GIT_REF_OID, GIT_REF_SYMBOLIC, Signature
 from . import utils
 
 
@@ -77,13 +77,13 @@ class ReferencesTest(utils.RepoTestCase):
     def test_reference_set_sha(self):
         NEW_COMMIT = '5ebeeebb320790caf276b9fc8b24546d63316533'
         reference = self.repo.lookup_reference('refs/heads/master')
-        reference.target = NEW_COMMIT
+        reference.set_target(NEW_COMMIT)
         self.assertEqual(reference.target.hex, NEW_COMMIT)
 
     def test_reference_set_sha_prefix(self):
         NEW_COMMIT = '5ebeeebb320790caf276b9fc8b24546d63316533'
         reference = self.repo.lookup_reference('refs/heads/master')
-        reference.target = NEW_COMMIT[0:6]
+        reference.set_target(NEW_COMMIT[0:6])
         self.assertEqual(reference.target.hex, NEW_COMMIT)
 
 
@@ -100,7 +100,7 @@ class ReferencesTest(utils.RepoTestCase):
     def test_set_target(self):
         reference = self.repo.lookup_reference('HEAD')
         self.assertEqual(reference.target, 'refs/heads/master')
-        reference.target = 'refs/heads/i18n'
+        reference.set_target('refs/heads/i18n')
         self.assertEqual(reference.target, 'refs/heads/i18n')
 
     def test_get_shorthand(self):
@@ -109,6 +109,16 @@ class ReferencesTest(utils.RepoTestCase):
         reference = self.repo.create_reference('refs/remotes/origin/master', LAST_COMMIT)
         self.assertEqual(reference.shorthand, 'origin/master')
 
+    def test_set_target_with_message(self):
+        reference = self.repo.lookup_reference('HEAD')
+        self.assertEqual(reference.target, 'refs/heads/master')
+        sig = Signature('foo', 'bar')
+        msg = 'Hello log'
+        reference.set_target('refs/heads/i18n', signature=sig, message=msg)
+        self.assertEqual(reference.target, 'refs/heads/i18n')
+        self.assertEqual(list(reference.log())[0].message, msg)
+        self.assertEqualSignature(list(reference.log())[0].committer, sig)
+
     def test_delete(self):
         repo = self.repo
 
@@ -124,8 +134,6 @@ class ReferencesTest(utils.RepoTestCase):
         self.assertRaises(GitError, getattr, reference, 'name')
         self.assertRaises(GitError, getattr, reference, 'type')
         self.assertRaises(GitError, getattr, reference, 'target')
-        self.assertRaises(GitError, setattr, reference, 'target', LAST_COMMIT)
-        self.assertRaises(GitError, setattr, reference, 'target', "a/b/c")
         self.assertRaises(GitError, reference.delete)
         self.assertRaises(GitError, reference.resolve)
         self.assertRaises(GitError, reference.rename, "refs/tags/version2")