Merge branch 'jk/strbuf-detach-always-non-null'

* jk/strbuf-detach-always-non-null:
  strbuf: always return a non-NULL value from strbuf_detach

strbuf.c

@@ -44,7 +44,9 @@ void strbuf_release(struct strbuf *sb)
 
 char *strbuf_detach(struct strbuf *sb, size_t *sz)
 {
-	char *res = sb->alloc ? sb->buf : NULL;
+	char *res;
+	strbuf_grow(sb, 0);
+	res = sb->buf;
 	if (sz)
 		*sz = sb->len;
 	strbuf_init(sb, 0);