More efficient check for environment equivalence when setting up Nodes.

2 files changed, 5 insertions, 1 deletions

diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index b5ed500..f3e9a3d 100644
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -79,6 +79,10 @@ RELEASE 0.96 - XXX
     of suffixes to be scanned by a given type of scanner, allowing these
     suffix lists to be easily added to or overridden.
 
+  - Speed up Node creation when calling a Builder by comparing whether two
+    Environments are the same object, not if their underlying dictionaries
+    are equivalent.
+
   From Gary Oberbrunner:
 
   - Add a --debug=presub option to print actions prior to substitution.
diff --git a/src/engine/SCons/Builder.py b/src/engine/SCons/Builder.py
index 3d1fa87..5971056 100644
--- a/src/engine/SCons/Builder.py
+++ b/src/engine/SCons/Builder.py
@@ -286,7 +286,7 @@ def _init_nodes(builder, env, overrides, tlist, slist):
         if t.side_effect:
             raise UserError, "Multiple ways to build the same target were specified for: %s" % str(t)
         if t.has_builder():
-            if t.env != env:
+            if not t.env is env:
                 t_contents = t.builder.action.get_contents(tlist, slist, t.env)
                 contents = t.builder.action.get_contents(tlist, slist, env)