merge-recursive: separate out xdl_merge() interface.

diff --git a/Documentation/git-read-tree.txt b/Documentation/git-read-tree.txt
index 0ff2890c7fb76155e08eaf9e361bf1eb6cf50f25..019c8bef7af2868af150b4a13472b8ce26744ea3 100644 (file)
--- a/Documentation/git-read-tree.txt
+++ b/Documentation/git-read-tree.txt
@@ -8,7 +8,7 @@ git-read-tree - Reads tree information into the index
 
 SYNOPSIS
 --------
-'git-read-tree' (<tree-ish> | [[-m [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] [--exclude-per-directory=<gitignore>] <tree-ish1> [<tree-ish2> [<tree-ish3>]])
+'git-read-tree' (<tree-ish> | [[-m [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] [--exclude-per-directory=<gitignore>] [--index-output=<file>] <tree-ish1> [<tree-ish2> [<tree-ish3>]])
 
 
 DESCRIPTION
@@ -86,6 +86,18 @@ OPTIONS
        file (usually '.gitignore') and allows such an untracked
        but explicitly ignored file to be overwritten.
 
+--index-output=<file>::
+       Instead of writing the results out to `$GIT_INDEX_FILE`,
+       write the resulting index in the named file.  While the
+       command is operating, the original index file is locked
+       with the same mechanism as usual.  The file must allow
+       to be rename(2)ed into from a temporary file that is
+       created next to the usual index file; typically this
+       means it needs to be on the same filesystem as the index
+       file itself, and you need write permission to the
+       directories the index file and index output file are
+       located in.
+
 <tree-ish#>::
        The id of the tree object(s) to be read/merged.