$git graph
*   9222703 (HEAD -> master) Merge branch 'b1'
|\
| * 0d73074 (b1) b1
* | c8a24c5 b2
|/
* 4c08cc1 init
$git diff 4c08cc1..c8a24c5
diff --git a/f b/f
index ed80ff7..3bd7c07 100644
--- a/f
+++ b/f
@@ -1,2 +1,4 @@
 <a>
+ <b
+  c="2"/>
 </a>
$git diff 4c08cc1..0d73074
diff --git a/f b/f
index ed80ff7..29916fc 100644
--- a/f
+++ b/f
@@ -1,2 +1,4 @@
 <a>
+ <b
+   c="1"/>
 </a>
$cat f
<a>
 <b
  c="2"/>
 <b
   c="1"/>
</a>
$