[PATCH] provide more errors for the "merge into empty head" case

[Paolo Bonzini <bonzini@gnu.org>]

--squash merges are not supported yet.  They could be implemented
by building the index from the merged-from branch, and doing a
single commit.

Non-fast-forward merges instead do not make sense, because you
cannot make a merge commit if you don't have a base in the
beginning.

Signed-off-by: Paolo Bonzini <bonzini@gnu.org>
---
 builtin-merge.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/builtin-merge.c b/builtin-merge.c
index b4c7eda..a3b9b10 100644
--- a/builtin-merge.c
+++ b/builtin-merge.c
@@ -869,6 +869,11 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		if (argc != 1)
 			die("Can merge only exactly one commit into "
 				"empty head");
+		if (squash)
+			die("Squash commit into empty head not supported yet");
+		if (!allow_fast_forward)
+			die("Non-fast-forward commit does not make sense into "
+			    "an empty head");
 		remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
 		if (!remote_head)
 			die("%s - not something we can merge", argv[0]);
-- 
1.5.5