fix(tests): handle list-type shared_preload_libraries in pg_upgrade

When extensions define shared_preload_libraries as a list (e.g., pg_cron,
pg_net), the test code needs to convert it to a comma-separated string
for use in pg_upgrade --old-options and --new-options flags. This fix
adds proper list-to-string conversion using lib.concatStringsSep.

Author: yvan-sraka

nix/ext/tests/default.nix

@@ -129,8 +129,14 @@ let
                     ${newPostgresql}/bin/pg_upgrade --old-datadir "${oldDataDir}" --new-datadir "${newDataDir}" \
                       --old-bindir "${oldPostgresql}/bin" --new-bindir "${newPostgresql}/bin" \
                       ${
+                        let
+                          oldLibs = oldSettings.shared_preload_libraries or "";
+                          newLibs = newSettings.shared_preload_libraries or "";
+                          oldLibsStr = if builtins.isList oldLibs then lib.concatStringsSep "," oldLibs else oldLibs;
+                          newLibsStr = if builtins.isList newLibs then lib.concatStringsSep "," newLibs else newLibs;
+                        in
                         if oldSettings ? shared_preload_libraries || newSettings ? shared_preload_libraries then
-                          " --old-options='-c shared_preload_libraries=${oldSettings.shared_preload_libraries or ""}' --new-options='-c shared_preload_libraries=${newSettings.shared_preload_libraries or ""}'"
+                          " --old-options='-c shared_preload_libraries=${oldLibsStr}' --new-options='-c shared_preload_libraries=${newLibsStr}'"
                         else
                           ""
                       }

nix/ext/tests/pgmq.nix

@@ -104,8 +104,14 @@ pkgs.testers.runNixOSTest {
                 ${newPostgresql}/bin/pg_upgrade --old-datadir "${oldDataDir}" --new-datadir "${newDataDir}" \
                   --old-bindir "${oldPostgresql}/bin" --new-bindir "${newPostgresql}/bin" \
                   ${
+                    let
+                      oldLibs = oldSettings.shared_preload_libraries or "";
+                      newLibs = newSettings.shared_preload_libraries or "";
+                      oldLibsStr = if builtins.isList oldLibs then lib.concatStringsSep "," oldLibs else oldLibs;
+                      newLibsStr = if builtins.isList newLibs then lib.concatStringsSep "," newLibs else newLibs;
+                    in
                     if oldSettings ? shared_preload_libraries || newSettings ? shared_preload_libraries then
-                      " --old-options='-c shared_preload_libraries=${oldSettings.shared_preload_libraries or ""}' --new-options='-c shared_preload_libraries=${newSettings.shared_preload_libraries or ""}'"
+                      " --old-options='-c shared_preload_libraries=${oldLibsStr}' --new-options='-c shared_preload_libraries=${newLibsStr}'"
                     else
                       ""
                   }