Avoid copying __builtin__ when evaluating variables. (Gary Oberbrunner)

2 files changed, 29 insertions, 0 deletions

diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index 6747261..9845e85 100644
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -154,6 +154,9 @@ RELEASE 0.97 - XXX
     will not be added to the construction environment unless it's set
     explicitly by the user or from an Options file.
 
+  - Avoid copying __builtin__ values into a construction environment's
+    dictionary when evaluating construction variables.
+
   From Chris Pawling:
 
   - Have the linkloc tool use $MSVS_VERSION to select the Microsoft
diff --git a/src/engine/SCons/Util.py b/src/engine/SCons/Util.py
index 4e81935..b713b57 100644
--- a/src/engine/SCons/Util.py
+++ b/src/engine/SCons/Util.py
@@ -692,9 +692,22 @@ def scons_subst(strSubst, env, mode=SUBST_RAW, target=None, source=None, dict=No
     if gvars is None:
         gvars = env.Dictionary()
 
+    # We're (most likely) going to eval() things.  If Python doesn't
+    # find a __builtin__ value in the global dictionary used for eval(),
+    # it copies the current __builtin__ values for you.  Avoid this by
+    # setting it explicitly and then deleting, so we don't pollute the
+    # construction environment Dictionary(ies) that are typically used
+    # for expansion.
+    gvars['__builtin__'] = __builtin__
+
     ss = StringSubber(env, mode, target, source, conv, gvars)
     result = ss.substitute(strSubst, dict)
 
+    try:
+        del gvars['__builtin__']
+    except KeyError:
+        pass
+
     if is_String(result):
         # Remove $(-$) pairs and any stuff in between,
         # if that's appropriate.
@@ -929,9 +942,22 @@ def scons_subst_list(strSubst, env, mode=SUBST_RAW, target=None, source=None, di
     if gvars is None:
         gvars = env.Dictionary()
 
+    # We're (most likely) going to eval() things.  If Python doesn't
+    # find a __builtin__ value in the global dictionary used for eval(),
+    # it copies the current __builtin__ values for you.  Avoid this by
+    # setting it explicitly and then deleting, so we don't pollute the
+    # construction environment Dictionary(ies) that are typically used
+    # for expansion.
+    gvars['__builtins__'] = __builtins__
+
     ls = ListSubber(env, mode, target, source, conv, gvars)
     ls.substitute(strSubst, dict, 0)
 
+    try:
+        del gvars['__builtins__']
+    except KeyError:
+        pass
+
     return ls.data
 
 def scons_subst_once(strSubst, env, key):