From c099655fc034c3be63017d0a3e112ea10928464a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carlos=20Mart=C3=ADn=20Nieto?= <cmn@dwim.me>
Date: Sat, 7 Feb 2015 20:23:45 +0100
Subject: [PATCH] TreeEntry: compare ids when two entrie sort equally

The function we were using `git_tree_entry_cmp()` is only meant for
git-compatible sorting in a tree and thus does not take the id into
account. This is however important in order to keep value equality. In
order to avoid issues with assymetry, we compare the id any time when
two entries are equal according to their position in a tree.
---
 src/tree.c        | 20 ++++++++++++++++++--
 test/test_tree.py | 13 +++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/src/tree.c b/src/tree.c
index e8f7111..e51e139 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -87,10 +87,20 @@ TreeEntry_oid__get__(TreeEntry *self)
     return TreeEntry_id__get__(self);
 }
 
+static int
+compare_ids(TreeEntry *a, TreeEntry *b)
+{
+    const git_oid *id_a, *id_b;
+    id_a = git_tree_entry_id(a->entry);
+    id_b = git_tree_entry_id(b->entry);
+    return git_oid_cmp(id_a, id_b);
+}
+
 PyObject *
 TreeEntry_richcompare(PyObject *a, PyObject *b, int op)
 {
     PyObject *res;
+    TreeEntry *ta, *tb;
     int cmp;
 
     /* We only support comparing to another tree entry */
@@ -99,7 +109,14 @@ TreeEntry_richcompare(PyObject *a, PyObject *b, int op)
         return Py_NotImplemented;
     }
 
-    cmp =git_tree_entry_cmp(((TreeEntry*)a)->entry, ((TreeEntry*)b)->entry);
+    ta = (TreeEntry *) a;
+    tb = (TreeEntry *) b;
+
+    /* This is sorting order, if they sort equally, we still need to compare the ids */
+    cmp = git_tree_entry_cmp(ta->entry, tb->entry);
+    if (cmp == 0)
+        cmp = compare_ids(ta, tb);
+
     switch (op) {
         case Py_LT:
             res = (cmp <= 0) ? Py_True: Py_False;
@@ -147,7 +164,6 @@ PyGetSetDef TreeEntry_getseters[] = {
     {NULL}
 };
 
-
 PyDoc_STRVAR(TreeEntry__doc__, "TreeEntry objects.");
 
 PyTypeObject TreeEntryType = {
diff --git a/test/test_tree.py b/test/test_tree.py
index 128fc75..6c8b707 100644
--- a/test/test_tree.py
+++ b/test/test_tree.py
@@ -32,6 +32,7 @@ from __future__ import unicode_literals
 import operator
 import unittest
 
+from pygit2 import TreeEntry
 from . import utils
 
 
@@ -71,6 +72,18 @@ class TreeTest(utils.BareRepoTestCase):
         self.assertTreeEntryEqual(tree['c/d'], sha, 'd', 0o0100644)
         self.assertRaisesWithArg(KeyError, 'ab/cd', lambda: tree['ab/cd'])
 
+    def test_equality(self):
+        tree_a = self.repo['18e2d2e9db075f9eb43bcb2daa65a2867d29a15e']
+        tree_b = self.repo['2ad1d3456c5c4a1c9e40aeeddb9cd20b409623c8']
+
+        self.assertNotEqual(tree_a['a'], tree_b['a'])
+        self.assertNotEqual(tree_a['a'], tree_b['b'])
+        self.assertEqual(tree_a['b'], tree_b['b'])
+
+    def test_sorting(self):
+        tree_a = self.repo['18e2d2e9db075f9eb43bcb2daa65a2867d29a15e']
+        self.assertEqual(list(tree_a), sorted(reversed(list(tree_a))))
+        self.assertNotEqual(list(tree_a), reversed(list(tree_a)))
 
     def test_read_subtree(self):
         tree = self.repo[TREE_SHA]