nixos/outline: fix crash at startup from "Failed to parse" on database URL (#536063)

nixos/modules/services/web-apps/outline.nix

@@ -836,12 +836,18 @@ in
           ${
             if (cfg.databaseUrl == "local") then
               ''
-                export DATABASE_URL="''${DATABASE_URL:-${lib.escapeShellArg localPostgresqlUrl}}"
+                if [ -z "''${DATABASE_URL:-}" ]; then
+                  DATABASE_URL=${lib.escapeShellArg localPostgresqlUrl}
+                fi
+                export DATABASE_URL
                 export PGSSLMODE="''${PGSSLMODE:-disable}"
               ''
             else
               ''
-                export DATABASE_URL="''${DATABASE_URL:-${lib.escapeShellArg cfg.databaseUrl}}"
+                if [ -z "''${DATABASE_URL:-}" ]; then
+                  DATABASE_URL=${lib.escapeShellArg cfg.databaseUrl}
+                fi
+                export DATABASE_URL
               ''
           }
 

nixos/tests/outline.nix

@@ -7,10 +7,7 @@
     xanderio
   ];
 
-  node.pkgsReadOnly = false;
-
-  nodes.outline = {
-    virtualisation.memorySize = 2 * 1024;
+  containers.outline = {
     services.outline = {
       enable = true;
       forceHttps = false;