do not write null sha1s to on-disk index

diff --git a/Documentation/git-sh-setup.txt b/Documentation/git-sh-setup.txt
index a2f346ca710e03a7f5c65574659ac578ab8bf615..5e5f1c89646cf4389bfd30ba8e90eb0552e80aab 100644 (file)
--- a/Documentation/git-sh-setup.txt
+++ b/Documentation/git-sh-setup.txt
@@ -68,6 +68,16 @@ require_work_tree_exists::
        cd_to_toplevel, which is impossible to do if there is no
        working tree.
 
+require_clean_work_tree <action> [<hint>]::
+       checks that the working tree and index associated with the
+       repository have no uncommitted changes to tracked files.
+       Otherwise it emits an error message of the form `Cannot
+       <action>: <reason>. <hint>`, and dies.  Example:
++
+----------------
+require_clean_work_tree rebase "Please commit or stash them."
+----------------
+
 get_author_ident_from_commit::
        outputs code for use with eval to set the GIT_AUTHOR_NAME,
        GIT_AUTHOR_EMAIL and GIT_AUTHOR_DATE variables for a given commit.