Convert commit_tree() to take strbuf as message

There wan't a way for commit_tree() to notice if the message the caller
prepared contained a NUL byte, as it did not take the length of the
message as a parameter. Use a pointer to a strbuf instead, so that we can
either choose to allow low-level plumbing commands to make commits that
contain NUL byte in its message, or forbid NUL everywhere by adding the
check in commit_tree(), in later patches.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

4 files changed, 6 insertions, 6 deletions

diff --git a/builtin/commit-tree.c b/builtin/commit-tree.c
index d083795e2..089586145 100644
--- a/builtin/commit-tree.c
+++ b/builtin/commit-tree.c
@@ -56,7 +56,7 @@ int cmd_commit_tree(int argc, const char **argv, const char *prefix)
 	if (strbuf_read(&buffer, 0, 0) < 0)
 		die_errno("git commit-tree: failed to read");
 
-	if (commit_tree(buffer.buf, tree_sha1, parents, commit_sha1, NULL)) {
+	if (commit_tree(&buffer, tree_sha1, parents, commit_sha1, NULL)) {
 		strbuf_release(&buffer);
 		return 1;
 	}
diff --git a/builtin/commit.c b/builtin/commit.c
index 8f2bebecf..849151e95 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1483,7 +1483,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		exit(1);
 	}
 
-	if (commit_tree(sb.buf, active_cache_tree->sha1, parents, sha1,
+	if (commit_tree(&sb, active_cache_tree->sha1, parents, sha1,
 			author_ident.buf)) {
 		rollback_index_files();
 		die(_("failed to write commit object"));
diff --git a/builtin/merge.c b/builtin/merge.c
index 27576c0f7..e066bf1b0 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -913,7 +913,7 @@ static int merge_trivial(struct commit *head)
 	parent->next->item = remoteheads->item;
 	parent->next->next = NULL;
 	prepare_to_commit();
-	if (commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL))
+	if (commit_tree(&merge_msg, result_tree, parent, result_commit, NULL))
 		die(_("failed to write commit object"));
 	finish(head, result_commit, "In-index merge");
 	drop_save();
@@ -945,7 +945,7 @@ static int finish_automerge(struct commit *head,
 	strbuf_addch(&merge_msg, '\n');
 	prepare_to_commit();
 	free_commit_list(remoteheads);
-	if (commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL))
+	if (commit_tree(&merge_msg, result_tree, parents, result_commit, NULL))
 		die(_("failed to write commit object"));
 	strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
 	finish(head, result_commit, buf.buf);
diff --git a/builtin/notes.c b/builtin/notes.c
index f8e437db0..5e32548cd 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -301,12 +301,12 @@ void commit_notes(struct notes_tree *t, const char *msg)
 		return; /* don't have to commit an unchanged tree */
 
 	/* Prepare commit message and reflog message */
-	strbuf_addstr(&buf, "notes: "); /* commit message starts at index 7 */
 	strbuf_addstr(&buf, msg);
 	if (buf.buf[buf.len - 1] != '\n')
 		strbuf_addch(&buf, '\n'); /* Make sure msg ends with newline */
 
-	create_notes_commit(t, NULL, buf.buf + 7, commit_sha1);
+	create_notes_commit(t, NULL, &buf, commit_sha1);
+	strbuf_insert(&buf, 0, "notes: ", 7); /* commit message starts at index 7 */
 	update_ref(buf.buf, t->ref, commit_sha1, NULL, 0, DIE_ON_ERR);
 
 	strbuf_release(&buf);