Fix pretrans lua script error for first installation (not upgrade)

(#2131236)

lv2.spec

@@ -2,7 +2,7 @@
 
 Name:           lv2
 Version:        1.18.8
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        Audio Plugin Standard
 
 # lv2specgen template.html is CC-AT-SA
@@ -114,7 +114,11 @@ table.insert(parent_dirs, hdir)
 for i = 1, #parent_dirs, 1 do -- not use ipairs here to guarantee order
     parent = parent_dirs[i]
 
-    for j, path in pairs(posix.dir(parent)) do
+    dir_entry = posix.dir(parent)
+    if not(dir_entry) then
+        goto skip_2
+    end
+    for j, path in pairs(dir_entry) do
         exclude_list = {"." , ".."}
         for k, ex in ipairs(exclude_list) do
             if path == ex then
@@ -131,6 +135,7 @@ for i = 1, #parent_dirs, 1 do -- not use ipairs here to guarantee order
 
         ::skip_1::
     end
+    ::skip_2::
 end
 
 -- Remove extra symlinks
@@ -195,6 +200,10 @@ end
 %doc %{_vpath_builddir}/doc/*
 
 %changelog
+* Fri Sep 30 2022 Mamoru TASAKA <mtasaka@fedoraproject.org> - 1.18.8-4
+- Fix pretrans lua script error for first installation (not upgrade)
+  (#2131236)
+
 * Fri Sep 23 2022 Mamoru TASAKA <mtasaka@fedoraproject.org> - 1.18.8-3
 - Remove all symlinks in previous -devel subpackage in %%pre_trans
   to ensure update transaction (#2123422)