Fix a problem where <implicit-dependency> had no effect unless

the target named by the property was also build (by virtue of being in
the same Jamfile and not marked as "explicit").


[SVN r32885]

v2/build/virtual-target.jam

@@ -746,6 +746,23 @@ class action
           actualize-source-type $(dependencies) : $(property-set) ] ;
         self.actual-sources += [ 
           actualize-source-type $(sources) : $(property-set) ] ;
+
+        # This is used to help bjam find dependencies in generated headers
+        # in other main targets.
+        # Say:
+        #
+        #   make a.h : ....... ;
+        #   exe hello : hello.cpp : <implicit-dependency>a.h ;
+        #
+        # However, for bjam to find the dependency the generated target must
+        # be actualized (i.e. have the jam target). In the above case,
+        # if we're building just hello ("bjam hello"), 'a.h' won't be
+        # actualized unless we do it here.
+        local implicit = [ $(self.properties).get <implicit-dependency> ] ;
+        for local i in $(implicit)
+        {
+            $(i:G=).actualize ;
+        }        
     }
 
     # Determined real properties when trying building with 'properties'.

v2/test/implicit_dependency.py

@@ -0,0 +1,45 @@
+#!/usr/bin/python
+
+#  Copyright (C) Vladimir Prus 2006.
+#  Distributed under the Boost Software License, Version 1.0. (See
+#  accompanying file LICENSE_1_0.txt or copy at
+#  http://www.boost.org/LICENSE_1_0.txt)
+
+#  Test the <implicit-dependency> is respected even if the
+#  target referred-to is not build itself, but only referred
+#  to by <implicit-dependency>.
+
+from BoostBuild import Tester, List
+import string
+
+t = Tester()
+
+t.write("Jamroot", """ 
+make a.h : : gen-header ;
+explicit a.h ;
+
+exe hello : hello.cpp : <implicit-dependency>a.h ;
+
+actions gen-header
+{
+    echo "int i;" > $(<)
+} 
+""")
+
+t.write("hello.cpp", """ 
+#include "a.h"
+
+int main()
+{
+    return i;
+} 
+""")
+
+
+
+t.run_build_system()
+
+t.expect_addition("bin/$toolset/debug/hello.exe")
+
+t.cleanup()
+

v2/test/test_all.py

@@ -139,6 +139,7 @@ tests = [ "rebuilds",
           "disambiguation",
           "clean",
           "lib_source_property",
+          "implicit_dependency",
           ]
 
 if os.name == 'posix':