From ae104381f8a70580cabd4938d53d392fffb4112a Mon Sep 17 00:00:00 2001
From: Kenneth Hoste <kenneth.hoste@ugent.be>
Date: Mon, 26 Oct 2020 11:05:02 +0100
Subject: [PATCH] also compile Lmod spider cache for alternate Lua versions if
 corresponding luac command is available

---
 src/update_lmod_system_cache_files.in | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/update_lmod_system_cache_files.in b/src/update_lmod_system_cache_files.in
index e3a089aea..37d82bee9 100644
--- a/src/update_lmod_system_cache_files.in
+++ b/src/update_lmod_system_cache_files.in
@@ -308,6 +308,18 @@ update_cache() {
        lua_ver=$(@path_to_lua@/lua -e 'print((_VERSION:gsub("Lua ","")))')
        @path_to_luac@ -o ${cache_file_name}.new.luac_$lua_ver ${cache_file_name}.lua
        install_new_cache luac_$lua_ver ${cache_file_name}
+
+       # also compile cache with other Lua 5.x versions, if corresponding luac is available
+       for alt_luac in $(ls @path_to_luac@-5.* 2> /dev/null); do
+           alt_lua_ver=$(basename ${alt_luac} | cut -f2 -d'-')
+           debug "Found potential alternate Lua version ${alt_lua_ver} (via ${alt_luac}"
+           # only for Lua versions different than what lua/luac commands correspond to (see above)
+           if [ "${alt_lua_ver}" != "${lua_ver}" ]; then
+               debug "Compiling cache file ${cache_file_name} for Lua ${alt_lua_ver}..."
+               ${alt_luac} -o ${cache_file_name}.new.luac_${alt_lua_ver} ${cache_file_name}.lua
+               install_new_cache luac_${alt_lua_ver} ${cache_file_name}
+           fi
+       done
     fi
 }