Fix bug in external module skipping logic

1 files changed, 5 insertions, 7 deletions

diff --git a/libbuild2/module.cxx b/libbuild2/module.cxx
index b31aa9c..9756860 100644
--- a/libbuild2/module.cxx
+++ b/libbuild2/module.cxx
@@ -591,17 +591,15 @@ namespace build2
                        << mmod;
         }
         else
-        {
-          // Reduce skipped external module to optional.
-          //
-          if (boot)
-            opt = true;
-
           i = loaded_modules.emplace (move (mmod), nullptr).first;
-        }
       }
     }
 
+    // Reduce skipped external module to optional.
+    //
+    if (boot && i->second == nullptr)
+      opt = true;
+
     // Now the iterator points to a submodule or to the main module, the
     // latter potentially NULL.
     //