Increment targe_count for inner operations only

3 files changed, 12 insertions, 6 deletions

diff --git a/build2/algorithm.cxx b/build2/algorithm.cxx
index 0e57c08..4e76e4a 100644
--- a/build2/algorithm.cxx
+++ b/build2/algorithm.cxx
@@ -879,6 +879,7 @@ namespace build2
 
     // Decrement the target count (see set_recipe() for details).
     //
+    if (a.inner ())
     {
       recipe_function** f (s.recipe.target<recipe_function*> ());
       if (f == nullptr || *f != &group_action)
diff --git a/build2/algorithm.ixx b/build2/algorithm.ixx
index 9baa650..7cad7ff 100644
--- a/build2/algorithm.ixx
+++ b/build2/algorithm.ixx
@@ -306,13 +306,18 @@ namespace build2
       // (which are not executed). Plus, group action means real recipe is in
       // the group so this also feels right conceptually.
       //
-      // Note that we will increment this count twice for the same target if
-      // we have non-noop recipes for both inner and outer operations. While
-      // not ideal, the alternative (trying to "merge" the count keeping track
+      // We also avoid increment this count twice for the same target if we
+      // have both the inner and outer operations. In our model the outer
+      // operation is either noop or it must delegate to the inner. While it's
+      // possible the inner is noop while the outer is not, it is not very
+      // likely. The alternative (trying to "merge" the count keeping track of
       // whether inner and/or outer is noop) gets hairy rather quickly.
       //
-      if (f == nullptr || *f != &group_action)
-        target_count.fetch_add (1, memory_order_relaxed);
+      if (l.action.inner ())
+      {
+        if (f == nullptr || *f != &group_action)
+          target_count.fetch_add (1, memory_order_relaxed);
+      }
     }
   }
 
diff --git a/build2/context.hxx b/build2/context.hxx
index 71035ad..97ba285 100644
--- a/build2/context.hxx
+++ b/build2/context.hxx
@@ -305,7 +305,7 @@ namespace build2
   //
   // The target count is incremented after a non-noop recipe is matched and
   // decremented after such recipe has been executed. If such a recipe has
-  // skipped updating the target, then it should increment the skip count.
+  // skipped executing the operation, then it should increment the skip count.
   // These two counters are used for progress monitoring and diagnostics.
   //
   extern atomic_count dependency_count;