merge: deprecate 'git merge <message> HEAD <commit>' syntax

We had this in "git merge" manual for eternity:

    'git merge' <msg> HEAD <commit>...

    [This] 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>...`.

With the update to "git merge" to make it understand what is
recorded in FETCH_HEAD directly, including Octopus merge cases, we
now can rewrite the use of this syntax in "git pull" with a simple
"git merge FETCH_HEAD".

Also there are quite a few fallouts in the test scripts, and it
turns out that "git cvsimport" also uses this old syntax to record
a merge.

Judging from this result, I would not be surprised if dropping the
support of the old syntax broke scripts people have written and been
relying on for the past ten years.  But at least we can start the
deprecation process by throwing a warning message when the syntax is
used.

With luck, we might be able to drop the support in a few years.

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

1 files changed, 3 insertions, 3 deletions

diff --git a/t/t6021-merge-criss-cross.sh b/t/t6021-merge-criss-cross.sh
index d15b313..213deec 100755
--- a/t/t6021-merge-criss-cross.sh
+++ b/t/t6021-merge-criss-cross.sh
@@ -48,7 +48,7 @@ echo "1
 " > file &&
 git commit -m "C3" file &&
 git branch C3 &&
-git merge "pre E3 merge" B A &&
+git merge -m "pre E3 merge" A &&
 echo "1
 2
 3 changed in E3, branch B. New file size
@@ -61,7 +61,7 @@ echo "1
 " > file &&
 git commit -m "E3" file &&
 git checkout A &&
-git merge "pre D8 merge" A C3 &&
+git merge -m "pre D8 merge" C3 &&
 echo "1
 2
 3 changed in C3, branch B
@@ -73,7 +73,7 @@ echo "1
 9" > file &&
 git commit -m D8 file'
 
-test_expect_success 'Criss-cross merge' 'git merge "final merge" A B'
+test_expect_success 'Criss-cross merge' 'git merge -m "final merge" B'
 
 cat > file-expect <<EOF
 1