merge script: --ff-only to disallow true merge

Port v1.6.6-rc0~62^2 (Teach 'git merge' and 'git pull' the option
--ff-only, 2009-10-29) to the old merge script.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/contrib/examples/git-merge.sh b/contrib/examples/git-merge.sh
index 410fa3c815680c3f9894b82bfa43545da91c75cb..dfd6e17946946825ad7a486e90d35a9f310020e6 100755 (executable)
--- a/contrib/examples/git-merge.sh
+++ b/contrib/examples/git-merge.sh
@@ -15,6 +15,7 @@ log                  add list of one-line log to merge commit message
 squash               create a single commit instead of doing a merge
 commit               perform a commit if the merge succeeds (default)
 ff                   allow fast-forward (default)
+ff-only              abort if fast-forward is not possible
 s,strategy=          merge strategy to use
 X=                   option for selected merge strategy
 m,message=           message to be used for the merge commit (if any)
@@ -45,6 +46,7 @@ use_strategies=
 xopt=
 
 allow_fast_forward=t
+fast_forward_only=
 allow_trivial_merge=t
 squash= no_commit= log_arg=
 
@@ -189,7 +191,13 @@ parse_config () {
                --no-ff)
                        test "$squash" != t ||
                                die "You cannot combine --squash with --no-ff."
+                       test "$fast_forward_only" != t ||
+                               die "You cannot combine --ff-only with --no-ff."
                        allow_fast_forward=f ;;
+               --ff-only)
+                       test "$allow_fast_forward" != f ||
+                               die "You cannot combine --ff-only with --no-ff."
+                       fast_forward_only=t ;;
                -s|--strategy)
                        shift
                        case " $all_strategies " in
@@ -412,8 +420,8 @@ t,1,"$head",*)
        # We are not doing octopus, not fast-forward, and have only
        # one common.
        git update-index --refresh 2>/dev/null
-       case "$allow_trivial_merge" in
-       t)
+       case "$allow_trivial_merge,$fast_forward_only" in
+       t,)
                # See if it is really trivial.
                git var GIT_COMMITTER_IDENT >/dev/null || exit
                echo "Trying really trivial in-index merge..."
@@ -452,6 +460,11 @@ t,1,"$head",*)
        ;;
 esac
 
+if test "$fast_forward_only" = t
+then
+       die "Not possible to fast-forward, aborting."
+fi
+
 # We are going to make a new commit.
 git var GIT_COMMITTER_IDENT >/dev/null || exit