git-apply: apply submodule changes

Apply "Subproject commit HEX" changes produced by git-diff.
As usual in the current git, only the superproject itself is actually
modified (possibly creating empty directories for new submodules).
Any checked-out submodule is left untouched and is not required to
be up-to-date.

With clean-ups from Junio C Hamano.

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/Documentation/git-apply.txt b/Documentation/git-apply.txt
index f03f661..4c7e3a2 100644
--- a/Documentation/git-apply.txt
+++ b/Documentation/git-apply.txt
@@ -171,6 +171,20 @@ apply.whitespace::
 	When no `--whitespace` flag is given from the command
 	line, this configuration item is used as the default.
 
+Submodules
+----------
+If the patch contains any changes to submodules then gitlink:git-apply[1]
+treats these changes as follows.
+
+If --index is specified (explicitly or implicitly), then the submodule
+commits must match the index exactly for the patch to apply.  If any
+of the submodules are checked-out, then these check-outs are completely
+ignored, i.e., they are not required to be up-to-date or clean and they
+are not updated.
+
+If --index is not specified, then the submodule commits in the patch
+are ignored and only the absence of presence of the corresponding
+subdirectory is checked and (if possible) updated.
 
 Author
 ------