From 6c8695e4028ae3793ddccfbccfa6522f4088528b Mon Sep 17 00:00:00 2001
From: Vladimir Prus <ghost@cs.msu.su>
Date: Mon, 11 Apr 2005 11:59:10 +0000
Subject: [PATCH] Tweak the generator pruning code that that generators with
 empty source type list are considered to accept anything and never pruned.

[SVN r28103]
---
 v2/build/generators.jam | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/v2/build/generators.jam b/v2/build/generators.jam
index 066af17e4..a3f04c7fe 100644
--- a/v2/build/generators.jam
+++ b/v2/build/generators.jam
@@ -117,7 +117,7 @@ class generator
                   # recusrive generators.construct-types call.
     
     : source-types *  # types that this generator can handle.  If
-        		      # empty, the generator can consume anything.
+                      # empty, the generator can consume anything.
     
     : target-types-and-names +   
       # types the generator will create and, optionally, names for
@@ -724,6 +724,14 @@ local rule viable-source-types-real ( target-type )
         
         for local g in $(generators)
         {
+            if ! [ $(g).source-types ]
+            {
+                # Empty source types -- everything can be accepted
+                result = * ;
+                generator = ;
+                t = ;
+            }
+              
             for local source-type in [ $(g).source-types ] 
             {
                 if ! $(source-type) in $(result) 
@@ -792,7 +800,11 @@ rule viable-source-types-for-generator-real ( generator )
             result += [ type.all-derived $(s) ] 
               [ generators.viable-source-types $(s) ] ;
         }
-        result = [ sequence.unique $(result) ] ;
+        result = [ sequence.unique $(result) ] ;        
+        if * in $(result)
+        {
+            result = * ;
+        }        
         return $(result) ;
     }        
 }