diff --git a/dir.c b/dir.c
index 39fce3bcba705f..efc87c2e405468 100644
--- a/dir.c
+++ b/dir.c
@@ -1550,14 +1550,6 @@ static void prep_exclude(struct dir_struct *dir,
 	if (dir->pattern)
 		return;
 
-	/*
-	 * Lazy initialization. All call sites currently just
-	 * memset(dir, 0, sizeof(*dir)) before use. Changing all of
-	 * them seems lots of work for little benefit.
-	 */
-	if (!dir->basebuf.buf)
-		strbuf_init(&dir->basebuf, PATH_MAX);
-
 	/* Read from the parent directories and push them down. */
 	current = stk ? stk->baselen : -1;
 	strbuf_setlen(&dir->basebuf, current < 0 ? 0 : current);
diff --git a/dir.h b/dir.h
index 83f46c0fb4c441..048a091cd8e610 100644
--- a/dir.h
+++ b/dir.h
@@ -342,7 +342,9 @@ struct dir_struct {
 	unsigned visited_directories;
 };
 
-#define DIR_INIT { 0 }
+#define DIR_INIT { \
+	.basebuf = STRBUF_INIT, \
+}
 
 struct dirent *readdir_skip_dot_and_dotdot(DIR *dirp);
 
diff --git a/unpack-trees.h b/unpack-trees.h
index 6fa6a4dfc3e450..b181860ce6e960 100644
--- a/unpack-trees.h
+++ b/unpack-trees.h
@@ -92,6 +92,7 @@ struct unpack_trees_options {
 	struct checkout_metadata meta;
 };
 #define UNPACK_TREES_OPTIONS_INIT { \
+	.msgs_to_free = STRVEC_INIT, \
 	.dir = DIR_INIT, \
 }