7 files changed, 25 insertions, 43 deletions

diff --git a/blob.c b/blob.c
index 5720a38ca2..1fcb8e44b0 100644
--- a/blob.c
+++ b/blob.c
@@ -8,14 +8,7 @@ struct blob *lookup_blob(const unsigned char *sha1)
 	struct object *obj = lookup_object(sha1);
 	if (!obj)
 		return create_object(sha1, alloc_blob_node());
-	if (!obj->type)
-		obj->type = OBJ_BLOB;
-	if (obj->type != OBJ_BLOB) {
-		error("Object %s is a %s, not a blob",
-		      sha1_to_hex(sha1), typename(obj->type));
-		return NULL;
-	}
-	return (struct blob *) obj;
+	return object_as_type(obj, OBJ_BLOB, 0);
 }
 
 int parse_blob_buffer(struct blob *item, void *buffer, unsigned long size)
diff --git a/commit.c b/commit.c
index eb24add866..65179f96ee 100644
--- a/commit.c
+++ b/commit.c
@@ -18,19 +18,6 @@ int save_commit_buffer = 1;
 
 const char *commit_type = "commit";
 
-static struct commit *check_commit(struct object *obj,
-				   const unsigned char *sha1,
-				   int quiet)
-{
-	if (obj->type != OBJ_COMMIT) {
-		if (!quiet)
-			error("Object %s is a %s, not a commit",
-			      sha1_to_hex(sha1), typename(obj->type));
-		return NULL;
-	}
-	return (struct commit *) obj;
-}
-
 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
 					      int quiet)
 {
@@ -38,7 +25,7 @@ struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
 
 	if (!obj)
 		return NULL;
-	return check_commit(obj, sha1, quiet);
+	return object_as_type(obj, OBJ_COMMIT, quiet);
 }
 
 struct commit *lookup_commit_reference(const unsigned char *sha1)
@@ -63,9 +50,7 @@ struct commit *lookup_commit(const unsigned char *sha1)
 	struct object *obj = lookup_object(sha1);
 	if (!obj)
 		return create_object(sha1, alloc_commit_node());
-	if (!obj->type)
-		obj->type = OBJ_COMMIT;
-	return check_commit(obj, sha1, 0);
+	return object_as_type(obj, OBJ_COMMIT, 0);
 }
 
 struct commit *lookup_commit_reference_by_name(const char *name)
diff --git a/object.c b/object.c
index 472aa8d5be..b2319f6246 100644
--- a/object.c
+++ b/object.c
@@ -158,6 +158,23 @@ void *create_object(const unsigned char *sha1, void *o)
 	return obj;
 }
 
+void *object_as_type(struct object *obj, enum object_type type, int quiet)
+{
+	if (obj->type == type)
+		return obj;
+	else if (obj->type == OBJ_NONE) {
+		obj->type = type;
+		return obj;
+	}
+	else {
+		if (!quiet)
+			error("object %s is a %s, not a %s",
+			      sha1_to_hex(obj->sha1),
+			      typename(obj->type), typename(type));
+		return NULL;
+	}
+}
+
 struct object *lookup_unknown_object(const unsigned char *sha1)
 {
 	struct object *obj = lookup_object(sha1);
diff --git a/object.h b/object.h
index 8020ace566..5e8d8ee548 100644
--- a/object.h
+++ b/object.h
@@ -81,6 +81,8 @@ struct object *lookup_object(const unsigned char *sha1);
 
 extern void *create_object(const unsigned char *sha1, void *obj);
 
+void *object_as_type(struct object *obj, enum object_type type, int quiet);
+
 /*
  * Returns the object, having parsed it to find out what it is.
  *
diff --git a/refs.c b/refs.c
index dc457742ea..7343565354 100644
--- a/refs.c
+++ b/refs.c
@@ -1531,9 +1531,8 @@ static enum peel_status peel_object(const unsigned char *name, unsigned char *sh
 
 	if (o->type == OBJ_NONE) {
 		int type = sha1_object_info(name, NULL);
-		if (type < 0)
+		if (type < 0 || !object_as_type(o, type, 0))
 			return PEEL_INVALID;
-		o->type = type;
 	}
 
 	if (o->type != OBJ_TAG)
diff --git a/tag.c b/tag.c
index 79552c716c..82d841bf2d 100644
--- a/tag.c
+++ b/tag.c
@@ -41,14 +41,7 @@ struct tag *lookup_tag(const unsigned char *sha1)
 	struct object *obj = lookup_object(sha1);
 	if (!obj)
 		return create_object(sha1, alloc_tag_node());
-	if (!obj->type)
-		obj->type = OBJ_TAG;
-	if (obj->type != OBJ_TAG) {
-		error("Object %s is a %s, not a tag",
-		      sha1_to_hex(sha1), typename(obj->type));
-		return NULL;
-	}
-	return (struct tag *) obj;
+	return object_as_type(obj, OBJ_TAG, 0);
 }
 
 static unsigned long parse_tag_date(const char *buf, const char *tail)
diff --git a/tree.c b/tree.c
index ed66575079..bb02c1caa4 100644
--- a/tree.c
+++ b/tree.c
@@ -184,14 +184,7 @@ struct tree *lookup_tree(const unsigned char *sha1)
 	struct object *obj = lookup_object(sha1);
 	if (!obj)
 		return create_object(sha1, alloc_tree_node());
-	if (!obj->type)
-		obj->type = OBJ_TREE;
-	if (obj->type != OBJ_TREE) {
-		error("Object %s is a %s, not a tree",
-		      sha1_to_hex(sha1), typename(obj->type));
-		return NULL;
-	}
-	return (struct tree *) obj;
+	return object_as_type(obj, OBJ_TREE, 0);
 }
 
 int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)