From b50093d044324ac9ed0cc39368a35a0733c41483 Mon Sep 17 00:00:00 2001
From: Benjamin Otte <otte@redhat.com>
Date: Fri, 21 Feb 2020 18:25:05 +0100
Subject: [PATCH] transform: Make sure the identity transform is equal to NULL

---
 gsk/gsktransform.c        |  7 +++++--
 testsuite/gsk/transform.c | 13 +++++++++++++
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/gsk/gsktransform.c b/gsk/gsktransform.c
index df6cb63bdd..19aa543b23 100644
--- a/gsk/gsktransform.c
+++ b/gsk/gsktransform.c
@@ -1683,8 +1683,11 @@ gsk_transform_equal (GskTransform *first,
   if (first == second)
     return TRUE;
 
-  if (first == NULL || second == NULL)
-    return FALSE;
+  if (first == NULL)
+    return gsk_transform_is_identity (second);
+
+  if (second == NULL)
+    return gsk_transform_is_identity (first);
 
   if (first->transform_class != second->transform_class)
     return FALSE;
diff --git a/testsuite/gsk/transform.c b/testsuite/gsk/transform.c
index 605d6f53cd..71ade76a49 100644
--- a/testsuite/gsk/transform.c
+++ b/testsuite/gsk/transform.c
@@ -332,6 +332,19 @@ test_identity (void)
   g_free (string);
 }
 
+static void
+test_identity_equal (void)
+{
+  GskTransform *id = gsk_transform_new ();
+
+  g_assert_true (gsk_transform_equal (NULL, NULL));
+  g_assert_true (gsk_transform_equal (id, NULL));
+  g_assert_true (gsk_transform_equal (NULL, id));
+  g_assert_true (gsk_transform_equal (id, id));
+
+  gsk_transform_unref (id);
+}
+
 static void
 test_print_parse (void)
 {