Subject: [PATCH] commit: introduce set_merge_remote_desc()

From: René Scharfe <[email-masked]>
Date: Sat, 13 Aug 2016 11:14:31 +0200

Add a helper function for allocating, populating and attaching struct
merge_remote_desc to a commit and use it consistently.  It allocates the
necessary memory in a single block.

commit.c::get_merge_parent() forgot to check for memory allocation
failures of strdup(3).

merge-recursive.c::make_virtual_commit() didn't duplicate the string for
the name member, even though one of it's callers (indirectly through
get_ref()) may pass the result of oid_to_hex(), i.e. a static buffer.

Signed-off-by: Rene Scharfe <[email-masked]>
---
 commit.c          | 18 +++++++++++-------
 commit.h          |  2 ++
 merge-recursive.c |  5 +----
 3 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/commit.c b/commit.c
index 71a360d..372b200 100644
--- a/commit.c
+++ b/commit.c
@@ -1576,6 +1576,15 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 	return result;
 }
 
+void set_merge_remote_desc(struct commit *commit,
+			   const char *name, struct object *obj)
+{
+	struct merge_remote_desc *desc;
+	FLEXPTR_ALLOC_STR(desc, name, name);
+	desc->obj = obj;
+	commit->util = desc;
+}
+
 struct commit *get_merge_parent(const char *name)
 {
 	struct object *obj;
@@ -1585,13 +1594,8 @@ struct commit *get_merge_parent(const char *name)
 		return NULL;
 	obj = parse_object(oid.hash);
 	commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
-	if (commit && !commit->util) {
-		struct merge_remote_desc *desc;
-		desc = xmalloc(sizeof(*desc));
-		desc->obj = obj;
-		desc->name = strdup(name);
-		commit->util = desc;
-	}
+	if (commit && !commit->util)
+		set_merge_remote_desc(commit, name, obj);
 	return commit;
 }
 
diff --git a/commit.h b/commit.h
index 23ae0c1..84bb507 100644
--- a/commit.h
+++ b/commit.h
@@ -365,6 +365,8 @@ struct merge_remote_desc {
 	const char *name;
 };
 #define merge_remote_util(commit) ((struct merge_remote_desc *)((commit)->util))
+extern void set_merge_remote_desc(struct commit *commit,
+				  const char *name, struct object *obj);
 
 /*
  * Given "name" from the command line to merge, find the commit object
diff --git a/merge-recursive.c b/merge-recursive.c
index e5243c2..e349126 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -73,12 +73,9 @@ static struct tree *shift_tree_object(struct tree *one, struct tree *two,
 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
 {
 	struct commit *commit = alloc_commit_node();
-	struct merge_remote_desc *desc = xmalloc(sizeof(*desc));
 
-	desc->name = comment;
-	desc->obj = (struct object *)commit;
+	set_merge_remote_desc(commit, comment, (struct object *)commit);
 	commit->tree = tree;
-	commit->util = desc;
 	commit->object.parsed = 1;
 	return commit;
 }
-- 
2.9.3