report no changes.
[NOTE]
-This is a bit of lie. In certain special cases, your index are
-allowed to be different from the tree of `HEAD` commit. The most
+This is a bit of a lie. In certain special cases, your index is
+allowed to be different from the tree of the `HEAD` commit. The most
notable case is when your `HEAD` commit is already ahead of what
is being merged, in which case your index can have arbitrary
-difference from your `HEAD` commit. Otherwise, your index entries
-are allowed have differences from your `HEAD` commit that match
-the result of trivial merge (e.g. you received the same patch
-from external source to produce the same result as what you are
+differences from your `HEAD` commit. Also, your index entries
+may have differences from your `HEAD` commit that match
+the result of a trivial merge (e.g. you received the same patch
+from an external source to produce the same result as what you are
merging). For example, if a path did not exist in the common
ancestor and your head commit but exists in the tree you are
merging into your repository, and if you already happen to have