diff --git a/commit.h b/commit.h
index 06c06df3ec..f3d2f57a89 100644
--- a/commit.h
+++ b/commit.h
@@ -27,7 +27,6 @@ extern int save_commit_buffer;
 extern const char *commit_type;
 
 /* While we can decorate any object with a name, it's only used for commits.. */
-extern struct decoration name_decoration;
 struct name_decoration {
 	struct name_decoration *next;
 	int type;
@@ -45,6 +44,7 @@ enum decoration_type {
 };
 
 void add_name_decoration(enum decoration_type type, const char *name, struct object *obj);
+const struct name_decoration *get_name_decoration(const struct object *obj);
 
 struct commit *lookup_commit(const unsigned char *sha1);
 struct commit *lookup_commit_reference(const unsigned char *sha1);
diff --git a/log-tree.c b/log-tree.c
index f7c6b035c9..2adf82ba02 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -12,7 +12,7 @@
 #include "sequencer.h"
 #include "line-log.h"
 
-struct decoration name_decoration = { "object names" };
+static struct decoration name_decoration = { "object names" };
 
 static char decoration_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_RESET,
@@ -83,6 +83,11 @@ void add_name_decoration(enum decoration_type type, const char *name, struct obj
 	res->next = add_decoration(&name_decoration, obj, res);
 }
 
+const struct name_decoration *get_name_decoration(const struct object *obj)
+{
+	return lookup_decoration(&name_decoration, obj);
+}
+
 static int add_ref_decoration(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
 {
 	struct object *obj;
@@ -177,13 +182,13 @@ void format_decorations(struct strbuf *sb,
 			int use_color)
 {
 	const char *prefix;
-	struct name_decoration *decoration;
+	const struct name_decoration *decoration;
 	const char *color_commit =
 		diff_get_color(use_color, DIFF_COMMIT);
 	const char *color_reset =
 		decorate_get_color(use_color, DECORATION_NONE);
 
-	decoration = lookup_decoration(&name_decoration, &commit->object);
+	decoration = get_name_decoration(&commit->object);
 	if (!decoration)
 		return;
 	prefix = " (";
diff --git a/revision.c b/revision.c
index f40ccf1426..46b9c349e8 100644
--- a/revision.c
+++ b/revision.c
@@ -473,7 +473,7 @@ static int rev_compare_tree(struct rev_info *revs,
 		 * If we are simplifying by decoration, then the commit
 		 * is worth showing if it has a tag pointing at it.
 		 */
-		if (lookup_decoration(&name_decoration, &commit->object))
+		if (get_name_decoration(&commit->object))
 			return REV_TREE_DIFFERENT;
 		/*
 		 * A commit that is not pointed by a tag is uninteresting