Fix bug in prerequisite iteration leave group support

2 files changed, 5 insertions, 1 deletions

diff --git a/build2/target b/build2/target
index dfc6abc..7a50a19 100644
--- a/build2/target
+++ b/build2/target
@@ -802,6 +802,8 @@ namespace build2
       // will normally only be known once the caller searched and matched
       // the group.
       //
+      // Also, the enter/leave group support is full of ugly, special cases.
+      //
     private:
       void
       switch_mode ();
diff --git a/build2/target.ixx b/build2/target.ixx
index 5cf5ca9..b9dfa48 100644
--- a/build2/target.ixx
+++ b/build2/target.ixx
@@ -57,7 +57,8 @@ namespace build2
 
     if (k_ == nullptr && g_.count != 0) // Iterating over a normal group.
     {
-      if (++j_ > g_.count)
+      if (g_.members == nullptr || // leave_group()
+          ++j_ > g_.count)
         g_.count = 0;
     }
 
@@ -133,6 +134,7 @@ namespace build2
       //
       j_ = 0;
       g_.count = 1;
+      g_.members = nullptr; // Ugly "special case signal" for operator++.
     }
   }
 }