bash: add the merge option --ff-only

diff --git a/builtin-merge.c b/builtin-merge.c
index c69a3051f38eb70f148015471d0c2df1df8db33b..c8d7bdecc4e91392fa9e2614a6b9790e48fc0abd 100644 (file)
--- a/builtin-merge.c
+++ b/builtin-merge.c
@@ -43,6 +43,7 @@ static const char * const builtin_merge_usage[] = {
 
 static int show_diffstat = 1, option_log, squash;
 static int option_commit = 1, allow_fast_forward = 1;
+static int fast_forward_only;
 static int allow_trivial = 1, have_message;
 static struct strbuf merge_msg;
 static struct commit_list *remoteheads;
@@ -167,6 +168,8 @@ static struct option builtin_merge_options[] = {
                "perform a commit if the merge succeeds (default)"),
        OPT_BOOLEAN(0, "ff", &allow_fast_forward,
                "allow fast forward (default)"),
+       OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
+               "abort if fast forward is not possible"),
        OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
                "merge strategy to use", option_parse_strategy),
        OPT_CALLBACK('m', "message", &merge_msg, "message",
@@ -843,7 +846,6 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
        const char *best_strategy = NULL, *wt_strategy = NULL;
        struct commit_list **remotes = &remoteheads;
 
-       setup_work_tree();
        if (file_exists(git_path("MERGE_HEAD")))
                die("You have not concluded your merge. (MERGE_HEAD exists)");
        if (read_cache_unmerged())
@@ -877,6 +879,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                option_commit = 0;
        }
 
+       if (!allow_fast_forward && fast_forward_only)
+               die("You cannot combine --no-ff with --ff-only.");
+
        if (!argc)
                usage_with_options(builtin_merge_usage,
                        builtin_merge_options);
@@ -1043,7 +1048,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                 * only one common.
                 */
                refresh_cache(REFRESH_QUIET);
-               if (allow_trivial) {
+               if (allow_trivial && !fast_forward_only) {
                        /* See if it is really trivial. */
                        git_committer_info(IDENT_ERROR_ON_NO_NAME);
                        printf("Trying really trivial in-index merge...\n");
@@ -1082,6 +1087,9 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
                }
        }
 
+       if (fast_forward_only)
+               die("Not possible to fast forward, aborting.");
+
        /* We are going to make a new commit. */
        git_committer_info(IDENT_ERROR_ON_NO_NAME);