Issue 2332: Convert from using StringIO.StringIO class to using the

forward-compatible io.StringIO class, with the addition of an "io"
compatibility module for Python versions before 2.6.

15 files changed, 131 insertions, 73 deletions

diff --git a/src/engine/SCons/Action.py b/src/engine/SCons/Action.py
index 9d497526..da68b7de 100644
--- a/src/engine/SCons/Action.py
+++ b/src/engine/SCons/Action.py
@@ -497,7 +497,7 @@ class _ActionAction(ActionBase):
             SCons.Util.AddMethod(self, batch_key, 'batch_key')
 
     def print_cmd_line(self, s, target, source, env):
-        sys.stdout.write(s + "\n")
+        sys.stdout.write(s + u"\n")
 
     def __call__(self, target, source, env,
                                exitstatfunc=_null,
@@ -536,7 +536,7 @@ class _ActionAction(ActionBase):
                 source = executor.get_all_sources()
             t = ' and '.join(map(str, target))
             l = '\n  '.join(self.presub_lines(env))
-            out = "Building %s with action:\n  %s\n" % (t, l)
+            out = u"Building %s with action:\n  %s\n" % (t, l)
             sys.stdout.write(out)
         cmd = None
         if show and self.strfunction:
diff --git a/src/engine/SCons/ActionTests.py b/src/engine/SCons/ActionTests.py
index 3f78812e..6b8b465d 100644
--- a/src/engine/SCons/ActionTests.py
+++ b/src/engine/SCons/ActionTests.py
@@ -23,6 +23,8 @@
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.compat
+
 # Define a null function and a null class for use as builder actions.
 # Where these are defined in the file seems to affect their byte-code
 # contents, so try to minimize changes by defining them here, before we
@@ -34,9 +36,9 @@ class GlobalActFunc:
     def __call__(self):
         pass
 
+import io
 import os
 import re
-import StringIO
 import sys
 import types
 import unittest
@@ -97,7 +99,7 @@ scons_env = SCons.Environment.Environment()
 
 # Capture all the stuff the Actions will print,
 # so it doesn't clutter the output.
-sys.stdout = StringIO.StringIO()
+sys.stdout = io.StringIO()
 
 class CmdStringHolder:
     def __init__(self, cmd, literal=None):
@@ -514,7 +516,7 @@ class _ActionActionTestCase(unittest.TestCase):
                 pass
             a = SCons.Action.Action(execfunc)
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             a.print_cmd_line("foo bar", None, None, None)
             s = sio.getvalue()
@@ -556,7 +558,7 @@ class _ActionActionTestCase(unittest.TestCase):
                 return 9
             b = SCons.Action.Action([firstfunc, execfunc, lastfunc])
             
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a("out", "in", env)
             assert result.status == 7, result
@@ -566,14 +568,14 @@ class _ActionActionTestCase(unittest.TestCase):
             a.chdir = 'xyz'
             expect = "os.chdir(%s)\nexecfunc(['out'], ['in'])\nos.chdir(%s)\n"
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a("out", "in", env)
             assert result.status == 7, result.status
             s = sio.getvalue()
             assert s == expect % (repr('xyz'), repr(test.workpath())), s
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a("out", "in", env, chdir='sub')
             assert result.status == 7, result.status
@@ -582,7 +584,7 @@ class _ActionActionTestCase(unittest.TestCase):
 
             a.chdir = None
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = b("out", "in", env)
             assert result.status == 7, result.status
@@ -591,14 +593,14 @@ class _ActionActionTestCase(unittest.TestCase):
 
             SCons.Action.execute_actions = 0
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a("out", "in", env)
             assert result == 0, result
             s = sio.getvalue()
             assert s == "execfunc(['out'], ['in'])\n", s
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = b("out", "in", env)
             assert result == 0, result
@@ -608,35 +610,35 @@ class _ActionActionTestCase(unittest.TestCase):
             SCons.Action.print_actions_presub = 1
             SCons.Action.execute_actions = 1
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a("out", "in", env)
             assert result.status == 7, result.status
             s = sio.getvalue()
             assert s == "Building out with action:\n  execfunc(target, source, env)\nexecfunc(['out'], ['in'])\n", s
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a("out", "in", env, presub=0)
             assert result.status == 7, result.status
             s = sio.getvalue()
             assert s == "execfunc(['out'], ['in'])\n", s
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a("out", "in", env, presub=1)
             assert result.status == 7, result.status
             s = sio.getvalue()
             assert s == "Building out with action:\n  execfunc(target, source, env)\nexecfunc(['out'], ['in'])\n", s
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = b(["out"], "in", env, presub=1)
             assert result.status == 7, result.status
             s = sio.getvalue()
             assert s == "Building out with action:\n  firstfunc(target, source, env)\nfirstfunc(['out'], ['in'])\nBuilding out with action:\n  execfunc(target, source, env)\nexecfunc(['out'], ['in'])\n", s
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = b(["out", "list"], "in", env, presub=1)
             assert result.status == 7, result.status
@@ -645,14 +647,14 @@ class _ActionActionTestCase(unittest.TestCase):
 
             a2 = SCons.Action.Action(execfunc)
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a2("out", "in", env)
             assert result.status == 7, result.status
             s = sio.getvalue()
             assert s == "Building out with action:\n  execfunc(target, source, env)\nexecfunc(['out'], ['in'])\n", s
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a2("out", "in", env, presub=0)
             assert result.status == 7, result.status
@@ -661,14 +663,14 @@ class _ActionActionTestCase(unittest.TestCase):
 
             SCons.Action.execute_actions = 0
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a2("out", "in", env, presub=0)
             assert result == 0, result
             s = sio.getvalue()
             assert s == "execfunc(['out'], ['in'])\n", s
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             result = a("out", "in", env, presub=0, execute=1, show=0)
             assert result.status == 7, result.status
diff --git a/src/engine/SCons/BuilderTests.py b/src/engine/SCons/BuilderTests.py
index e4ddaec5..de6d2be9 100644
--- a/src/engine/SCons/BuilderTests.py
+++ b/src/engine/SCons/BuilderTests.py
@@ -32,10 +32,10 @@ import SCons.compat
 def Func():
     pass
 
+import io
 import os.path
 import re
 import sys
-import StringIO
 import unittest
 import UserList
 
@@ -48,7 +48,7 @@ import SCons.Errors
 import SCons.Subst
 import SCons.Util
 
-sys.stdout = StringIO.StringIO()
+sys.stdout = io.StringIO()
 
 # Initial setup of the common environment for all tests,
 # a temporary working directory containing a
diff --git a/src/engine/SCons/Environment.py b/src/engine/SCons/Environment.py
index 267b73dc..1fd763d3 100644
--- a/src/engine/SCons/Environment.py
+++ b/src/engine/SCons/Environment.py
@@ -591,7 +591,7 @@ class SubstitutionEnvironment:
         out,err = p.communicate()
         status = p.wait()
         if err:
-            sys.stderr.write(err)
+            sys.stderr.write(unicode(err))
         if status:
             raise OSError("'%s' exited %d" % (command, status))
         return out
diff --git a/src/engine/SCons/EnvironmentTests.py b/src/engine/SCons/EnvironmentTests.py
index 25404082..3a2cd8a9 100644
--- a/src/engine/SCons/EnvironmentTests.py
+++ b/src/engine/SCons/EnvironmentTests.py
@@ -26,8 +26,8 @@ __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 import SCons.compat
 
 import copy
+import io
 import os
-import StringIO
 import sys
 import TestCmd
 import unittest
@@ -645,21 +645,21 @@ sys.exit(0)
         python = '"' + sys.executable + '"'
 
         try:
-            sys.stderr = StringIO.StringIO()
+            sys.stderr = io.StringIO()
             cmd = '%s %s' % (python, test.workpath('stdout.py'))
             output = env.backtick(cmd)
             errout = sys.stderr.getvalue()
             assert output == 'this came from stdout.py\n', output
             assert errout == '', errout
 
-            sys.stderr = StringIO.StringIO()
+            sys.stderr = io.StringIO()
             cmd = '%s %s' % (python, test.workpath('stderr.py'))
             output = env.backtick(cmd)
             errout = sys.stderr.getvalue()
             assert output == '', output
             assert errout == 'this came from stderr.py\n', errout
 
-            sys.stderr = StringIO.StringIO()
+            sys.stderr = io.StringIO()
             cmd = '%s %s' % (python, test.workpath('fail.py'))
             try:
                 env.backtick(cmd)
@@ -668,7 +668,7 @@ sys.exit(0)
             else:
                 self.fail("did not catch expected OSError")
 
-            sys.stderr = StringIO.StringIO()
+            sys.stderr = io.StringIO()
             cmd = '%s %s' % (python, test.workpath('echo.py'))
             env['ENV'] = os.environ.copy()
             env['ENV']['ECHO'] = 'this came from ECHO'
diff --git a/src/engine/SCons/Node/FS.py b/src/engine/SCons/Node/FS.py
index 4e455da3..acba76ea 100644
--- a/src/engine/SCons/Node/FS.py
+++ b/src/engine/SCons/Node/FS.py
@@ -37,7 +37,6 @@ from __future__ import generators  ### KEEP FOR COMPATIBILITY FIXERS
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
 from itertools import izip
-import cStringIO
 import fnmatch
 import os
 import os.path
@@ -3111,7 +3110,7 @@ class FileFinder:
         if verbose and not callable(verbose):
             if not SCons.Util.is_String(verbose):
                 verbose = "find_file"
-            _verbose = '  %s: ' % verbose
+            _verbose = u'  %s: ' % verbose
             verbose = lambda s: sys.stdout.write(_verbose + s)
 
         filedir, filename = os.path.split(filename)
diff --git a/src/engine/SCons/Node/FSTests.py b/src/engine/SCons/Node/FSTests.py
index e68b389a..8e581f12 100644
--- a/src/engine/SCons/Node/FSTests.py
+++ b/src/engine/SCons/Node/FSTests.py
@@ -23,6 +23,8 @@
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.compat
+
 import os
 import os.path
 import sys
@@ -2891,11 +2893,11 @@ class find_fileTestCase(unittest.TestCase):
         # 'bar/baz' as a Dir.
         SCons.Node.FS.find_file('baz/no_file_here', paths)
 
-        import StringIO
+        import io
         save_sys_stdout = sys.stdout
 
         try:
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             SCons.Node.FS.find_file('foo2', paths, verbose="xyz")
             expect = "  xyz: looking for 'foo2' in '.' ...\n" + \
@@ -2903,7 +2905,7 @@ class find_fileTestCase(unittest.TestCase):
             c = sio.getvalue()
             assert c == expect, c
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             SCons.Node.FS.find_file('baz2', paths, verbose=1)
             expect = "  find_file: looking for 'baz2' in '.' ...\n" + \
@@ -2912,7 +2914,7 @@ class find_fileTestCase(unittest.TestCase):
             c = sio.getvalue()
             assert c == expect, c
 
-            sio = StringIO.StringIO()
+            sio = io.StringIO()
             sys.stdout = sio
             SCons.Node.FS.find_file('on_disk', paths, verbose=1)
             expect = "  find_file: looking for 'on_disk' in '.' ...\n" + \
diff --git a/src/engine/SCons/SConf.py b/src/engine/SCons/SConf.py
index e8b6c0eb..ac019ad3 100644
--- a/src/engine/SCons/SConf.py
+++ b/src/engine/SCons/SConf.py
@@ -28,9 +28,11 @@ Autoconf-like configuration support.
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.compat
+
+import io
 import os
 import re
-import StringIO
 import sys
 import traceback
 
@@ -176,7 +178,7 @@ class Streamer:
     """
     def __init__(self, orig):
         self.orig = orig
-        self.s = StringIO.StringIO()
+        self.s = io.StringIO()
 
     def write(self, str):
         if self.orig:
diff --git a/src/engine/SCons/SConfTests.py b/src/engine/SCons/SConfTests.py
index 26f21f39..7e48862e 100644
--- a/src/engine/SCons/SConfTests.py
+++ b/src/engine/SCons/SConfTests.py
@@ -23,16 +23,18 @@
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.compat
+
+import io
 import os
 import re
-import StringIO
 import sys
 from types import *
 import unittest
 
 import TestCmd
 
-sys.stdout = StringIO.StringIO()
+sys.stdout = io.StringIO()
 
 if sys.platform == 'win32':
     existing_lib = "msvcrt"
diff --git a/src/engine/SCons/Taskmaster.py b/src/engine/SCons/Taskmaster.py
index b2c4204e..1b42bcb2 100644
--- a/src/engine/SCons/Taskmaster.py
+++ b/src/engine/SCons/Taskmaster.py
@@ -165,7 +165,7 @@ class Task:
         the Action is actually called to build the targets.
         """
         T = self.tm.trace
-        if T: T.write(self.trace_message('Task.prepare()', self.node))
+        if T: T.write(self.trace_message(u'Task.prepare()', self.node))
 
         # Now that it's the appropriate time, give the TaskMaster a
         # chance to raise any exceptions it encountered while preparing
@@ -218,7 +218,7 @@ class Task:
         prepare(), executed() or failed().
         """
         T = self.tm.trace
-        if T: T.write(self.trace_message('Task.execute()', self.node))
+        if T: T.write(self.trace_message(u'Task.execute()', self.node))
 
         try:
             everything_was_cached = 1
@@ -370,7 +370,7 @@ class Task:
         This is the default behavior for building only what's necessary.
         """
         T = self.tm.trace
-        if T: T.write(self.trace_message('Task.make_ready_current()',
+        if T: T.write(self.trace_message(u'Task.make_ready_current()',
                                          self.node))
 
         self.out_of_date = []
@@ -415,7 +415,7 @@ class Task:
         that can be put back on the candidates list.
         """
         T = self.tm.trace
-        if T: T.write(self.trace_message('Task.postprocess()', self.node))
+        if T: T.write(self.trace_message(u'Task.postprocess()', self.node))
 
         # We may have built multiple targets, some of which may have
         # common parents waiting for this build.  Count up how many
@@ -432,7 +432,7 @@ class Task:
             # A node can only be in the pending_children set if it has
             # some waiting_parents.
             if t.waiting_parents:
-                if T: T.write(self.trace_message('Task.postprocess()',
+                if T: T.write(self.trace_message(u'Task.postprocess()',
                                                  t,
                                                  'removing'))
                 pending_children.discard(t)
@@ -451,7 +451,7 @@ class Task:
 
         for p, subtract in parents.items():
             p.ref_count = p.ref_count - subtract
-            if T: T.write(self.trace_message('Task.postprocess()',
+            if T: T.write(self.trace_message(u'Task.postprocess()',
                                              p,
                                              'adjusted parent ref count'))
             if p.ref_count == 0:
@@ -735,12 +735,12 @@ class Taskmaster:
         self.ready_exc = None
 
         T = self.trace
-        if T: T.write('\n' + self.trace_message('Looking for a node to evaluate'))
+        if T: T.write(u'\n' + self.trace_message('Looking for a node to evaluate'))
 
         while True:
             node = self.next_candidate()
             if node is None:
-                if T: T.write(self.trace_message('No candidate anymore.') + '\n')
+                if T: T.write(self.trace_message('No candidate anymore.') + u'\n')
                 return None
 
             node = node.disambiguate()
@@ -763,7 +763,7 @@ class Taskmaster:
             else:
                 S = None
 
-            if T: T.write(self.trace_message('    Considering node %s and its children:' % self.trace_node(node)))
+            if T: T.write(self.trace_message(u'    Considering node %s and its children:' % self.trace_node(node)))
 
             if state == NODE_NO_STATE:
                 # Mark this node as being on the execution stack:
@@ -771,7 +771,7 @@ class Taskmaster:
             elif state > NODE_PENDING:
                 # Skip this node if it has already been evaluated:
                 if S: S.already_handled = S.already_handled + 1
-                if T: T.write(self.trace_message('       already handled (executed)'))
+                if T: T.write(self.trace_message(u'       already handled (executed)'))
                 continue
 
             executor = node.get_executor()
@@ -802,7 +802,7 @@ class Taskmaster:
             for child in chain(executor.get_all_prerequisites(), children):
                 childstate = child.get_state()
 
-                if T: T.write(self.trace_message('       ' + self.trace_node(child)))
+                if T: T.write(self.trace_message(u'       ' + self.trace_node(child)))
 
                 if childstate == NODE_NO_STATE:
                     children_not_visited.append(child)
@@ -861,7 +861,7 @@ class Taskmaster:
                     # count so we can be put back on the list for
                     # re-evaluation when they've all finished.
                     node.ref_count =  node.ref_count + child.add_to_waiting_parents(node)
-                    if T: T.write(self.trace_message('     adjusted ref count: %s, child %s' %
+                    if T: T.write(self.trace_message(u'     adjusted ref count: %s, child %s' %
                                   (self.trace_node(node), repr(str(child)))))
 
                 if T:
@@ -887,7 +887,7 @@ class Taskmaster:
             # The default when we've gotten through all of the checks above:
             # this node is ready to be built.
             if S: S.build = S.build + 1
-            if T: T.write(self.trace_message('Evaluating %s\n' %
+            if T: T.write(self.trace_message(u'Evaluating %s\n' %
                                              self.trace_node(node)))
 
             # For debugging only:
diff --git a/src/engine/SCons/TaskmasterTests.py b/src/engine/SCons/TaskmasterTests.py
index 65d10b59..917bb622 100644
--- a/src/engine/SCons/TaskmasterTests.py
+++ b/src/engine/SCons/TaskmasterTests.py
@@ -23,6 +23,8 @@
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.compat
+
 import copy
 import sys
 import unittest
@@ -1054,9 +1056,9 @@ class TaskmasterTestCase(unittest.TestCase):
     def test_trace(self):
         """Test Taskmaster tracing
         """
-        import StringIO
+        import io
 
-        trace = StringIO.StringIO()
+        trace = io.StringIO()
         n1 = Node("n1")
         n2 = Node("n2")
         n3 = Node("n3", [n1, n2])
diff --git a/src/engine/SCons/Util.py b/src/engine/SCons/Util.py
index 8aa5f238..4ada2736 100644
--- a/src/engine/SCons/Util.py
+++ b/src/engine/SCons/Util.py
@@ -161,7 +161,7 @@ class DisplayEngine:
     def print_it(self, text, append_newline=1):
         if append_newline: text = text + '\n'
         try:
-            sys.stdout.write(text)
+            sys.stdout.write(unicode(text))
         except IOError:
             # Stdout might be connected to a pipe that has been closed
             # by now. The most likely reason for the pipe being closed
@@ -242,17 +242,18 @@ def print_tree(root, child_func, prune=0, showtags=0, margin=[0], visited={}):
     if showtags:
 
         if showtags == 2:
-            print ' E         = exists'
-            print '  R        = exists in repository only'
-            print '   b       = implicit builder'
-            print '   B       = explicit builder'
-            print '    S      = side effect'
-            print '     P     = precious'
-            print '      A    = always build'
-            print '       C   = current'
-            print '        N  = no clean'
-            print '         H = no cache'
-            print ''
+            legend = (' E         = exists\n' +
+                      '  R        = exists in repository only\n' +
+                      '   b       = implicit builder\n' +
+                      '   B       = explicit builder\n' +
+                      '    S      = side effect\n' +
+                      '     P     = precious\n' +
+                      '      A    = always build\n' +
+                      '       C   = current\n' +
+                      '        N  = no clean\n' +
+                      '         H = no cache\n' +
+                      '\n')
+            sys.stdout.write(unicode(legend))
 
         tags = ['[']
         tags.append(' E'[IDX(root.exists())])
@@ -277,10 +278,10 @@ def print_tree(root, child_func, prune=0, showtags=0, margin=[0], visited={}):
     children = child_func(root)
 
     if prune and rname in visited and children:
-        print ''.join(tags + margins + ['+-[', rname, ']'])
+        sys.stdout.write(''.join(tags + margins + ['+-[', rname, ']']) + u'\n')
         return
 
-    print ''.join(tags + margins + ['+-', rname])
+    sys.stdout.write(''.join(tags + margins + ['+-', rname]) + u'\n')
 
     visited[rname] = 1
 
diff --git a/src/engine/SCons/UtilTests.py b/src/engine/SCons/UtilTests.py
index ad271278..fd7862c7 100644
--- a/src/engine/SCons/UtilTests.py
+++ b/src/engine/SCons/UtilTests.py
@@ -23,9 +23,11 @@
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+import SCons.compat
+
+import io
 import os
 import os.path
-import StringIO
 import sys
 import unittest
 
@@ -171,24 +173,24 @@ class UtilTestCase(unittest.TestCase):
         try:
             node, expect, withtags = self.tree_case_1()
 
-            sys.stdout = StringIO.StringIO()
+            sys.stdout = io.StringIO()
             print_tree(node, get_children)
             actual = sys.stdout.getvalue()
             assert expect == actual, (expect, actual)
 
-            sys.stdout = StringIO.StringIO()
+            sys.stdout = io.StringIO()
             print_tree(node, get_children, showtags=1)
             actual = sys.stdout.getvalue()
             assert withtags == actual, (withtags, actual)
 
             node, expect, withtags = self.tree_case_2(prune=0)
 
-            sys.stdout = StringIO.StringIO()
+            sys.stdout = io.StringIO()
             print_tree(node, get_children, 1)
             actual = sys.stdout.getvalue()
             assert expect == actual, (expect, actual)
 
-            sys.stdout = StringIO.StringIO()
+            sys.stdout = io.StringIO()
             # The following call should work here:
             #    print_tree(node, get_children, 1, showtags=1)
             # For some reason I don't understand, though, *this*
@@ -678,7 +680,7 @@ class UtilTestCase(unittest.TestCase):
 
     def test_LogicalLines(self):
         """Test the LogicalLines class"""
-        fobj = StringIO.StringIO(r"""
+        fobj = io.StringIO(r"""
 foo \
 bar \
 baz
diff --git a/src/engine/SCons/compat/__init__.py b/src/engine/SCons/compat/__init__.py
index 792b77a0..0b70c5d1 100644
--- a/src/engine/SCons/compat/__init__.py
+++ b/src/engine/SCons/compat/__init__.py
@@ -125,6 +125,12 @@ except AttributeError:
     del filter
 
 try:
+    import io
+except ImportError:
+    # Pre-2.6 Python has no io module.
+    import_as('_scons_io', 'io')
+
+try:
     import itertools
 except ImportError:
     # Pre-2.3 Python has no itertools module.
diff --git a/src/engine/SCons/compat/_scons_io.py b/src/engine/SCons/compat/_scons_io.py
new file mode 100644
index 00000000..784021dc
--- /dev/null
+++ b/src/engine/SCons/compat/_scons_io.py
@@ -0,0 +1,40 @@
+#
+# __COPYRIGHT__
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
+# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+#
+
+__doc__ = """
+io compatibility module for older (pre-2.6) Python versions
+
+This does not not NOT (repeat, *NOT*) provide complete io
+functionality.  It only wraps the portions of io functionality used
+by SCons, in an interface that looks enough like io for our purposes.
+"""
+
+__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
+
+from cStringIO import StringIO
+
+# Local Variables:
+# tab-width:4
+# indent-tabs-mode:nil
+# End:
+# vim: set expandtab tabstop=4 shiftwidth=4: