Change prerequisite cleaning "limit" from subdirectories to same project

One day we will get this right.

3 files changed, 14 insertions, 9 deletions

diff --git a/build2/algorithm.ixx b/build2/algorithm.ixx
index a405c30..3f0bab9 100644
--- a/build2/algorithm.ixx
+++ b/build2/algorithm.ixx
@@ -101,7 +101,11 @@ namespace build2
   search_and_match_prerequisites (action a, target& t)
   {
     search_and_match_prerequisites (
-      a, t, a.operation () != clean_id ? dir_path () : t.dir);
+      a,
+      t,
+      (a.operation () != clean_id
+       ? dir_path ()
+       : t.root_scope ().out_path ()));
   }
 
   inline void
@@ -114,7 +118,7 @@ namespace build2
       // through groups since the group target should clean eveything
       // up. A bit of an optimization.
       //
-      search_and_match_prerequisites (a, t, t.dir);
+      search_and_match_prerequisites (a, t, t.root_scope ().out_path ());
   }
 
   target_state
diff --git a/build2/cxx/compile.cxx b/build2/cxx/compile.cxx
index b07019d..df2b798 100644
--- a/build2/cxx/compile.cxx
+++ b/build2/cxx/compile.cxx
@@ -81,8 +81,10 @@ namespace build2
       // code (below) takes care of the ones it is adding.
       //
       // When cleaning, ignore prerequisites that are not in the same
-      // or a subdirectory of ours.
+      // or a subdirectory of our project root.
       //
+      scope& rs (t.root_scope ());
+
       link::search_paths_cache lib_paths; // Extract lazily.
 
       for (prerequisite_member p: group_prerequisite_members (a, t))
@@ -115,7 +117,7 @@ namespace build2
 
         target& pt (p.search ());
 
-        if (a.operation () == clean_id && !pt.dir.sub (t.dir))
+        if (a.operation () == clean_id && !pt.dir.sub (rs.out_path ()))
           continue;
 
         build2::match (a, pt);
@@ -128,7 +130,6 @@ namespace build2
       //
       if (a == perform_update_id)
       {
-        scope& rs (t.root_scope ());
         const string& sys (as<string> (*rs["cxx.target.system"]));
 
         // The cached prerequisite target should be the same as what is in
diff --git a/build2/cxx/link.cxx b/build2/cxx/link.cxx
index f9fa69d..5ed36b7 100644
--- a/build2/cxx/link.cxx
+++ b/build2/cxx/link.cxx
@@ -543,7 +543,7 @@ namespace build2
       // files as well as search and match.
       //
       // When cleaning, ignore prerequisites that are not in the same
-      // or a subdirectory of ours.
+      // or a subdirectory of our project root.
       //
       for (prerequisite_member p: group_prerequisite_members (a, t))
       {
@@ -562,7 +562,7 @@ namespace build2
           if (pt == nullptr)
             pt = &p.search ();
 
-          if (a.operation () == clean_id && !pt->dir.sub (t.dir))
+          if (a.operation () == clean_id && !pt->dir.sub (rs.out_path ()))
             continue; // Skip.
 
           // If this is the obj{} or lib{} target group, then pick the
@@ -624,9 +624,9 @@ namespace build2
         target& ot (search (o_type, d, *cp.tk.name, nullptr, cp.scope));
 
         // If we are cleaning, check that this target is in the same or
-        // a subdirectory of ours.
+        // a subdirectory of our project root.
         //
-        if (a.operation () == clean_id && !ot.dir.sub (t.dir))
+        if (a.operation () == clean_id && !ot.dir.sub (rs.out_path ()))
         {
           // If we shouldn't clean obj{}, then it is fair to assume
           // we shouldn't clean cxx{} either (generated source will