git-merge: a deprecation notice of the ancient command line syntax

The ancient form of git merge command used in the original sample script
has been copied from Linus and are still found everywhere, I think, and
people may still have it in their scripts, but on the other hand, it is so
unintuitive that even people reasonably familiar with git are surprised by
accidentally triggering the support to parse this ancient form.

Gently nudge people to upgrade their script to more recent and readable
style for eventual removal of the original syntax.

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

diff --git a/builtin-merge.c b/builtin-merge.c
index b6b84286b26a4317dfd5185ae83fd861c6f9fa7d..6bf841e78c403600427f00d3e3a545da6f43aa3c 100644 (file)
--- a/builtin-merge.c
+++ b/builtin-merge.c
@@ -789,6 +789,11 @@ static int suggest_conflicts(void)
        return 1;
 }
 
+static const char deprecation_warning[] =
+       "'git merge <msg> HEAD <commit>' is deprecated. Please update\n"
+       "your script to use 'git merge -m <msg> <commit>' instead.\n"
+       "In future versions of git, this syntax will be removed.";
+
 static struct commit *is_old_style_invocation(int argc, const char **argv)
 {
        struct commit *second_token = NULL;
@@ -802,6 +807,7 @@ static struct commit *is_old_style_invocation(int argc, const char **argv)
                        die("'%s' is not a commit", argv[1]);
                if (hashcmp(second_token->object.sha1, head))
                        return NULL;
+               warning(deprecation_warning);
        }
        return second_token;
 }