Make the 'explicit' rule always operate on the current project.

[SVN r32654]

v2/build/project.jam

@@ -876,7 +876,11 @@ module project-rules
     rule explicit ( target-names * )
     {
         import project ;
-        local t = [ project.target $(__name__) ] ;
+        # If 'explicit' is used in a helper rule defined in Jamroot,
+        # and inherited by children, then most of the time 
+        # we want 'explicit' to operate on the Jamfile where
+        # the helper rule is invoked.
+        local t = [ project.current ] ;
         for local n in $(target-names)
         {            
             $(t).mark-target-as-explicit $(n) ;

v2/test/explicit.py

@@ -36,5 +36,40 @@ t.expect_nothing_more()
 t.run_build_system("hello2")
 t.expect_addition("bin/$toolset/debug/hello2.exe")
 
+t.rm(".")
+
+
+# Test that 'explicit' used in a helper rule applies to the current project,
+# and not to the Jamfile where the helper rule is defined.
+t.write("Jamroot", """ 
+rule myinstall ( name : target )
+{
+    install $(name)-bin : $(target) ;
+    explicit $(name)-bin ;
+    alias $(name) : $(name)-bin ;
+} 
+""")
+
+t.write("sub/a.cpp", """ 
+""")
+
+t.write("sub/Jamfile", """ 
+myinstall dist : a.cpp ;
+""")
+
+t.run_build_system(subdir="sub")
+t.expect_addition("sub/dist-bin/a.cpp")
+
+t.rm("sub/dist-bin")
+
+t.write("sub/Jamfile", """ 
+myinstall dist : a.cpp ;
+explicit dist ;
+
+""")
+
+t.run_build_system(subdir="sub")
+t.expect_nothing_more()
+
 
 t.cleanup()