diff --git a/builtin/fsck.c b/builtin/fsck.c
index 59c77c1baa..8d13794b14 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -104,23 +104,26 @@ static int objerror(struct object *obj, const char *err)
 }
 
 static int fsck_error_func(struct fsck_options *o,
-	struct object *obj, int type, const char *message)
+			   const struct object_id *oid,
+			   enum object_type object_type,
+			   int msg_type, const char *message)
 {
-	switch (type) {
+	switch (msg_type) {
 	case FSCK_WARN:
 		/* TRANSLATORS: e.g. warning in tree 01bfda: <more explanation> */
 		fprintf_ln(stderr, _("warning in %s %s: %s"),
-			   printable_type(&obj->oid, obj->type),
-			   describe_object(&obj->oid), message);
+			   printable_type(oid, object_type),
+			   describe_object(oid), message);
 		return 0;
 	case FSCK_ERROR:
 		/* TRANSLATORS: e.g. error in tree 01bfda: <more explanation> */
 		fprintf_ln(stderr, _("error in %s %s: %s"),
-			   printable_type(&obj->oid, obj->type),
-			   describe_object(&obj->oid), message);
+			   printable_type(oid, object_type),
+			   describe_object(oid), message);
 		return 1;
 	default:
-		BUG("%d (FSCK_IGNORE?) should never trigger this callback", type);
+		BUG("%d (FSCK_IGNORE?) should never trigger this callback",
+		    msg_type);
 	}
 }
 
diff --git a/fsck.c b/fsck.c
index 124c0184d4..c036ba09ab 100644
--- a/fsck.c
+++ b/fsck.c
@@ -305,7 +305,8 @@ static int report(struct fsck_options *options, struct object *object,
 
 	va_start(ap, fmt);
 	strbuf_vaddf(&sb, fmt, ap);
-	result = options->error_func(options, object, msg_type, sb.buf);
+	result = options->error_func(options, &object->oid, object->type,
+				     msg_type, sb.buf);
 	strbuf_release(&sb);
 	va_end(ap);
 
@@ -983,13 +984,15 @@ int fsck_object(struct object *obj, void *data, unsigned long size,
 }
 
 int fsck_error_function(struct fsck_options *o,
-	struct object *obj, int msg_type, const char *message)
+			const struct object_id *oid,
+			enum object_type object_type,
+			int msg_type, const char *message)
 {
 	if (msg_type == FSCK_WARN) {
-		warning("object %s: %s", fsck_describe_object(o, &obj->oid), message);
+		warning("object %s: %s", fsck_describe_object(o, oid), message);
 		return 0;
 	}
-	error("object %s: %s", fsck_describe_object(o, &obj->oid), message);
+	error("object %s: %s", fsck_describe_object(o, oid), message);
 	return 1;
 }
 
diff --git a/fsck.h b/fsck.h
index 36cfa463af..69cf715e79 100644
--- a/fsck.h
+++ b/fsck.h
@@ -27,10 +27,12 @@ typedef int (*fsck_walk_func)(struct object *obj, int type, void *data, struct f
 
 /* callback for fsck_object, type is FSCK_ERROR or FSCK_WARN */
 typedef int (*fsck_error)(struct fsck_options *o,
-	struct object *obj, int type, const char *message);
+			  const struct object_id *oid, enum object_type object_type,
+			  int msg_type, const char *message);
 
 int fsck_error_function(struct fsck_options *o,
-	struct object *obj, int type, const char *message);
+			const struct object_id *oid, enum object_type object_type,
+			int msg_type, const char *message);
 
 struct fsck_options {
 	fsck_walk_func walk;