index: replace has_conflicts by conflicts returning None

README.rst

@@ -99,7 +99,7 @@ Changelog
 - New ``Repository.state_cleanup()``
   `#386 <https://github.com/libgit2/pygit2/pull/386>`_
 
-- New ``Index.has_conflicts`` and ``Index.conflicts`` #345
+- New ```Index.conflicts``
   `#345 <https://github.com/libgit2/pygit2/issues/345>`_
   `#389 <https://github.com/libgit2/pygit2/pull/389>`_
 

pygit2/index.py

@@ -203,12 +203,6 @@ def add(self, path_or_entry):
 
         check_error(err, True)
 
-    @property
-    def has_conflicts(self):
-        """Whether this Index contains conflict information
-        """
-        return C.git_index_has_conflicts(self._index) != 0
-
     def diff_to_workdir(self, flags=0, context_lines=3, interhunk_lines=0):
         """diff_to_workdir(flags=0, context_lines=3, interhunk_lines=0) -> Diff
 
@@ -290,11 +284,20 @@ def diff_to_tree(self, tree, flags=0, context_lines=3, interhunk_lines=0):
 
         return Diff.from_c(bytes(ffi.buffer(cdiff)[:]), self._repo)
 
+
+    #
+    # Conflicts
+    #
+    _conflicts = None
+
     @property
     def conflicts(self):
         """A collection of conflict information
 
-        This presents a mapping interface with the paths as keys. You
+        If there are no conflicts None is returned. Otherwise return an object
+        that represents the conflicts in the index.
+
+        This object presents a mapping interface with the paths as keys. You
         can use the ``del`` operator to remove a conflict form the Index.
 
         Each conflict is made up of three elements. Access or iteration
@@ -306,7 +309,11 @@ def conflicts(self):
         These elements may be None depending on which sides exist for
         the particular conflict.
         """
-        if not hasattr(self, '_conflicts'):
+        if not C.git_index_has_conflicts(self._index):
+            self._conflicts = None
+            return None
+
+        if self._conflicts is None:
             self._conflicts = ConflictCollection(self)
 
         return self._conflicts

test/test_merge.py

@@ -81,7 +81,7 @@ def test_merge_no_fastforward_conflicts(self):
         self.assertFalse(analysis & GIT_MERGE_ANALYSIS_FASTFORWARD)
 
         self.repo.merge(branch_id)
-        self.assertTrue(self.repo.index.has_conflicts)
+        self.assertTrue(self.repo.index.conflicts is not None)
         status = pygit2.GIT_STATUS_WT_NEW | pygit2.GIT_STATUS_INDEX_DELETED
         # Asking twice to assure the reference counting is correct
         self.assertEqual({'.gitignore': status}, self.repo.status())
@@ -114,7 +114,7 @@ def test_merge_no_fastforward_conflicts(self):
         self.assertFalse(analysis & GIT_MERGE_ANALYSIS_FASTFORWARD)
 
         self.repo.merge(branch_id)
-        self.assertTrue(self.repo.index.has_conflicts)
+        self.assertTrue(self.repo.index.conflicts is not None)
         self.assertRaises(KeyError, self.repo.index.conflicts.__getitem__, 'some-file')
         ancestor, ours, theirs = self.repo.index.conflicts['.gitignore']
         self.assertEqual(None, ancestor)
@@ -126,13 +126,18 @@ def test_merge_no_fastforward_conflicts(self):
         # Checking the index works as expected
         self.repo.index.add('.gitignore')
         self.repo.index.write()
-        self.assertRaises(KeyError, self.repo.index.conflicts.__getitem__, '.gitignore')
+        self.assertTrue(self.repo.index.conflicts is None)
 
     def test_merge_remove_conflicts(self):
         other_branch_tip = '1b2bae55ac95a4be3f8983b86cd579226d0eb247'
         self.repo.merge(other_branch_tip)
         idx = self.repo.index
-        self.assertTrue(idx.has_conflicts)
-        self.assertRaises(KeyError, idx.conflicts.__delitem__, 'some-file')
+        conflicts = idx.conflicts
+        self.assertTrue(conflicts is not None)
+        try:
+            conflicts['.gitignore']
+        except KeyError:
+            self.fail("conflicts['.gitignore'] raised KeyError unexpectedly")
         del idx.conflicts['.gitignore']
-        self.assertFalse(idx.has_conflicts)
+        self.assertRaises(KeyError, conflicts.__getitem__, '.gitignore')
+        self.assertTrue(idx.conflicts is None)