[PATCH] merge: drop 'git merge <message> HEAD <commit>' syntax

[Junio C Hamano <gitster@pobox.com>]

And then if we and our users survived the previous "start warning if
the old syntax is used" patch for a few years, we could apply this
to actually drop the support for the ancient syntax.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/git-merge.txt |  7 +------
 builtin/merge.c             | 38 +-------------------------------------
 2 files changed, 2 insertions(+), 43 deletions(-)

diff --git a/Documentation/git-merge.txt b/Documentation/git-merge.txt
index 1f94908..4a2f519 100644
--- a/Documentation/git-merge.txt
+++ b/Documentation/git-merge.txt
@@ -12,7 +12,6 @@ SYNOPSIS
 'git merge' [-n] [--stat] [--no-commit] [--squash] [--[no-]edit]
 	[-s <strategy>] [-X <strategy-option>] [-S[<key-id>]]
 	[--[no-]rerere-autoupdate] [-m <msg>] [<commit>...]
-'git merge' <msg> HEAD <commit>...
 'git merge' --abort
 
 DESCRIPTION
@@ -44,11 +43,7 @@ a log message from the user describing the changes.
     D---E---F---G---H master
 ------------
 
-The second syntax (<msg> `HEAD` <commit>...) is supported for
-historical reasons.  Do not use it from the command line or in
-new scripts.  It is the same as `git merge -m <msg> <commit>...`.
-
-The third syntax ("`git merge --abort`") can only be run after the
+The second syntax ("`git merge --abort`") can only be run after the
 merge has resulted in conflicts. 'git merge --abort' will abort the
 merge process and try to reconstruct the pre-merge state. However,
 if there were uncommitted changes when the merge started (and
diff --git a/builtin/merge.c b/builtin/merge.c
index 0795358..a4ddd31 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -43,7 +43,6 @@ struct strategy {
 
 static const char * const builtin_merge_usage[] = {
 	N_("git merge [<options>] [<commit>...]"),
-	N_("git merge [<options>] <msg> HEAD <commit>"),
 	N_("git merge --abort"),
 	NULL
 };
@@ -902,24 +901,6 @@ static int suggest_conflicts(void)
 	return 1;
 }
 
-static struct commit *is_old_style_invocation(int argc, const char **argv,
-					      const unsigned char *head)
-{
-	struct commit *second_token = NULL;
-	if (argc > 2) {
-		unsigned char second_sha1[20];
-
-		if (get_sha1(argv[1], second_sha1))
-			return NULL;
-		second_token = lookup_commit_reference_gently(second_sha1, 0);
-		if (!second_token)
-			die(_("'%s' is not a commit"), argv[1]);
-		if (hashcmp(second_token->object.sha1, head))
-			return NULL;
-	}
-	return second_token;
-}
-
 static int evaluate_result(void)
 {
 	int cnt = 0;
@@ -1171,24 +1152,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		usage_with_options(builtin_merge_usage,
 			builtin_merge_options);
 
-	/*
-	 * This could be traditional "merge <msg> HEAD <commit>..."  and
-	 * the way we can tell it is to see if the second token is HEAD,
-	 * but some people might have misused the interface and used a
-	 * commit-ish that is the same as HEAD there instead.
-	 * Traditional format never would have "-m" so it is an
-	 * additional safety measure to check for it.
-	 */
-
-	if (!have_message && head_commit &&
-	    is_old_style_invocation(argc, argv, head_commit->object.sha1)) {
-		warning("old-style 'git merge <msg> HEAD <commit>' is deprecated.");
-		strbuf_addstr(&merge_msg, argv[0]);
-		head_arg = argv[1];
-		argv += 2;
-		argc -= 2;
-		remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
-	} else if (!head_commit) {
+	if (!head_commit) {
 		struct commit *remote_head;
 		/*
 		 * If the merged head is a valid one there is no reason
-- 
2.3.4-475-g3180e2e