git-commit --allow-empty

It does not usually make sense to record a commit that has the exact
same tree as its sole parent commit and that is why git-commit prevents
you from making such a mistake, but when data from foreign scm is
involved, it is a different story.  We are equipped to represent such an
(perhaps insane, perhaps by mistake, or perhaps done on purpose) empty
change, and it is better to represent it bypassing the safety valve for
native use.

This is primarily for use by foreign scm interface scripts.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt
index d4bfd49ce12ebe8f7b172d6f682d64ccbce66087..a7ef71ff99ced2f973d8e4c857d49e75ec65a908 100644 (file)
--- a/Documentation/git-commit.txt
+++ b/Documentation/git-commit.txt
@@ -10,7 +10,7 @@ SYNOPSIS
 [verse]
 'git-commit' [-a | --interactive] [-s] [-v] [-u]
           [(-c | -C) <commit> | -F <file> | -m <msg> | --amend]
-          [--no-verify] [-e] [--author <author>]
+          [--allow-empty] [--no-verify] [-e] [--author <author>]
           [--] [[-i | -o ]<file>...]
 
 DESCRIPTION
@@ -89,6 +89,12 @@ OPTIONS
        This option bypasses the pre-commit hook.
        See also link:hooks.html[hooks].
 
+--allow-empty::
+       Usually recording a commit that has the exact same tree as its
+       sole parent commit and the command prevents you from making such
+       a mistake.  This option bypasses the safety, and is primarily
+       for use by foreign scm interface scripts.
+
 -e|--edit::
        The message taken from file with `-F`, command line with
        `-m`, and from file with `-C` are usually used as the

diff --git a/git-commit.sh b/git-commit.sh
index cef76a77754190338add5b2bb61435fca5193b61..2c4a4062a5317c51601fc4c644c96a7f75e1ef2c 100755 (executable)
--- a/git-commit.sh
+++ b/git-commit.sh
@@ -74,6 +74,7 @@ trap '
 
 all=
 also=
+allow_empty=f
 interactive=
 only=
 logfile=
@@ -114,6 +115,10 @@ do
        -a|--a|--al|--all)
                all=t
                ;;
+       --allo|--allow|--allow-|--allow-e|--allow-em|--allow-emp|\
+       --allow-empt|--allow-empty)
+               allow_empty=t
+               ;;
        --au=*|--aut=*|--auth=*|--autho=*|--author=*)
                force_author="${1#*=}"
                ;;
@@ -515,9 +520,11 @@ else
        # we need to check if there is anything to commit
        run_status >/dev/null
 fi
-case "$?,$PARENTS" in
-0,* | *,-p' '?*-p' '?*)
-       # a merge commit can record the same tree as its parent.
+case "$allow_empty,$?,$PARENTS" in
+t,* | ?,0,* | ?,*,-p' '?*-p' '?*)
+       # an explicit --allow-empty, or a merge commit can record the
+       # same tree as its parent.  Otherwise having commitable paths
+       # is required.
        ;;
 *)
        rm -f "$GIT_DIR/COMMIT_EDITMSG" "$GIT_DIR/SQUASH_MSG"

diff --git a/t/t7501-commit.sh b/t/t7501-commit.sh
index 2e7bcb016ac94f150423446b2fbce2d61eb7bced..0316ecf5a16792f226725eb9626ad77c369877bb 100755 (executable)
--- a/t/t7501-commit.sh
+++ b/t/t7501-commit.sh
@@ -256,6 +256,13 @@ test_expect_success 'same tree (single parent)' '
 
 '
 
+test_expect_success 'same tree (single parent) --allow-empty' '
+
+       git commit --allow-empty -m "forced empty" &&
+       git cat-file commit HEAD | grep forced
+
+'
+
 test_expect_success 'same tree (merge and amend merge)' '
 
        git checkout -b side HEAD^ &&