From dbb7a5ffefefa1e6439464cac47ebfd90a913aa7 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 8 Nov 2018 12:45:33 +0200
Subject: Fix bug in override logic for command line variable with project
 visibility

---
 build2/scope.cxx | 16 +++++++++++-----
 build2/scope.hxx |  6 ++++++
 build2/scope.ixx | 12 ++++++++++++
 3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/build2/scope.cxx b/build2/scope.cxx
index b9dabe8..49263d4 100644
--- a/build2/scope.cxx
+++ b/build2/scope.cxx
@@ -225,9 +225,9 @@ namespace build2
 
     const scope* s;
 
-    // Return true if the override applies. Note that it expects vars and proj
-    // to be not NULL; if there is nothing "more inner", then any override
-    // will still be "visible".
+    // Return true if the override applies to a value from vars/proj. Note
+    // that it expects vars and proj to be not NULL; if there is nothing "more
+    // inner", then any override will still be "visible".
     //
     auto applies = [&s] (const variable* o,
                          const variable_map* vars,
@@ -246,9 +246,15 @@ namespace build2
       }
       case variable_visibility::project:
       {
-        // Does not apply if in a different project.
+        // Does not apply if in a subproject.
         //
-        if (proj != s->root_scope ())
+        // Note that before we used to require the same project but that
+        // missed values that are "visible" from the outer projects.
+        //
+        // If root scope is NULL, then we are looking at the global scope.
+        //
+        const scope* rs (s->root_scope ());
+        if (rs != nullptr && rs->sub_root (*proj))
           return false;
 
         break;
diff --git a/build2/scope.hxx b/build2/scope.hxx
index 770f320..7929bce 100644
--- a/build2/scope.hxx
+++ b/build2/scope.hxx
@@ -70,6 +70,12 @@ namespace build2
     scope*       weak_scope ();
     const scope* weak_scope () const;
 
+    // Return true if the specified root scope is a sub-scope of this root
+    // scope. Note that both scopes must be root.
+    //
+    bool
+    sub_root (const scope&) const;
+
     // Variables.
     //
   public:
diff --git a/build2/scope.ixx b/build2/scope.ixx
index 9a93e9d..ac71e82 100644
--- a/build2/scope.ixx
+++ b/build2/scope.ixx
@@ -39,4 +39,16 @@ namespace build2
       for (; r->parent_->root_ != nullptr; r = r->parent_->root_) ;
     return r;
   }
+
+  inline bool scope::
+  sub_root (const scope& r) const
+  {
+    // Scan the parent root scope chain looking for this scope.
+    //
+    for (const scope* pr (&r); (pr = pr->parent_->root_) != nullptr; )
+      if (pr == this)
+        return true;
+
+    return false;
+  }
 }
-- 
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