diff -r 9c0b835d4cc2 -r bd9d1ce274c9 src/Pure/Tools/build.scala
--- a/src/Pure/Tools/build.scala	Sun Jul 26 21:53:29 2020 +0200
+++ b/src/Pure/Tools/build.scala	Sun Jul 26 22:28:43 2020 +0200
@@ -216,7 +216,7 @@
           }
           else Nil
 
-        if (options.bool("pide_session")) {
+        if (options.bool("pide_session") || true /* FIXME test */) {
           val resources = new Resources(sessions_structure, deps(parent))
           val session =
             new Session(options, resources) {