[PATCH v2] commit: don't use-editor when allow-empty-message

[Ramkumar Ramachandra <artagnon@gmail.com>]

Commit a24a41e (git-commit: only append a newline to -m mesg if
necessary, 2013-02-18) introduced a regression: when
--allow-empty-message is used and an empty message is explicitly
specified with -m "", git commit still launches $EDITOR unnecessarily.
The commit (correctly) fixes opt_parse_m() to not fill in two newlines
into the message buffer unconditionally.  The real problem is that
launching $EDITOR only depends on use_editor and whether message is
empty.  Fix the problem by setting explicit_message in the codepath
where an explicit string is passed via -m, and then checking it before
launching $EDITOR.

Reported-by: Mislav Marohnić <mislav.marohnic@gmail.com>
Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com>
---
 Works?

 builtin/commit.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/builtin/commit.c b/builtin/commit.c
index d2f30d9..7d72ba7 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -108,6 +108,7 @@ static const char *cleanup_arg;
 static enum commit_whence whence;
 static int use_editor = 1, include_status = 1;
 static int show_ignored_in_status;
+static int explicit_message = 0;
 static const char *only_include_assumed;
 static struct strbuf message = STRBUF_INIT;
 
@@ -128,6 +129,7 @@ static int opt_parse_m(const struct option *opt, const char *arg, int unset)
 			strbuf_addch(buf, '\n');
 		strbuf_addstr(buf, arg);
 		strbuf_complete_line(buf);
+		explicit_message = 1;
 	}
 	return 0;
 }
@@ -824,7 +826,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
 		     git_path(commit_editmsg), hook_arg1, hook_arg2, NULL))
 		return 0;
 
-	if (use_editor) {
+	if (use_editor && !explicit_message) {
 		char index[PATH_MAX];
 		const char *env[2] = { NULL };
 		env[0] =  index;
-- 
1.8.3.1.g33669de.dirty