centralize the preferred pickle protocol; use highest protocol.

4 files changed, 20 insertions, 10 deletions

diff --git a/src/engine/SCons/SConsign.py b/src/engine/SCons/SConsign.py
index cb089aa0..3a5e5c0b 100644
--- a/src/engine/SCons/SConsign.py
+++ b/src/engine/SCons/SConsign.py
@@ -39,6 +39,8 @@ import pickle
 import SCons.dblite
 import SCons.Warnings
 
+from SCons.compat import PICKLE_PROTOCOL
+
 def corrupt_dblite_warning(filename):
     SCons.Warnings.warn(SCons.Warnings.CorruptSConsignWarning,
                         "Ignoring corrupt .sconsign file: %s"%filename)
@@ -272,7 +274,7 @@ class DB(Base):
         path = normcase(self.dir.get_internal_path())
         for key, entry in self.entries.items():
             entry.convert_to_sconsign()
-        db[path] = pickle.dumps(self.entries, 1)
+        db[path] = pickle.dumps(self.entries, PICKLE_PROTOCOL)
 
         if sync:
             try:
@@ -360,7 +362,7 @@ class DirFile(Dir):
                 return
         for key, entry in self.entries.items():
             entry.convert_to_sconsign()
-        pickle.dump(self.entries, file, 1)
+        pickle.dump(self.entries, file, PICKLE_PROTOCOL)
         file.close()
         if fname != self.sconsign:
             try:
diff --git a/src/engine/SCons/Tool/msvs.py b/src/engine/SCons/Tool/msvs.py
index 6df4928f..02b9a348 100644
--- a/src/engine/SCons/Tool/msvs.py
+++ b/src/engine/SCons/Tool/msvs.py
@@ -54,6 +54,7 @@ import SCons.Warnings
 
 from .MSCommon import msvc_exists, msvc_setup_env_once
 from SCons.Defaults import processDefines
+from SCons.compat import PICKLE_PROTOCOL
 
 ##############################################################################
 # Below here are the classes and functions for generation of
@@ -641,10 +642,10 @@ class _GenerateV6DSP(_DSPGenerator):
 
         if self.nokeep == 0:
             # now we pickle some data and add it to the file -- MSDEV will ignore it.
-            pdata = pickle.dumps(self.configs,1)
+            pdata = pickle.dumps(self.configs,PICKLE_PROTOCOL)
             pdata = base64.encodestring(pdata)
             self.file.write(pdata + '\n')
-            pdata = pickle.dumps(self.sources,1)
+            pdata = pickle.dumps(self.sources,PICKLE_PROTOCOL)
             pdata = base64.encodestring(pdata)
             self.file.write(pdata + '\n')
 
@@ -913,10 +914,10 @@ class _GenerateV7DSP(_DSPGenerator, _GenerateV7User):
 
         if self.nokeep == 0:
             # now we pickle some data and add it to the file -- MSDEV will ignore it.
-            pdata = pickle.dumps(self.configs,1)
+            pdata = pickle.dumps(self.configs,PICKLE_PROTOCOL)
             pdata = base64.encodestring(pdata)
             self.file.write('<!-- SCons Data:\n' + pdata + '\n')
-            pdata = pickle.dumps(self.sources,1)
+            pdata = pickle.dumps(self.sources,PICKLE_PROTOCOL)
             pdata = base64.encodestring(pdata)
             self.file.write(pdata + '-->\n')
 
@@ -1232,10 +1233,10 @@ class _GenerateV10DSP(_DSPGenerator, _GenerateV10User):
 
         if self.nokeep == 0:
             # now we pickle some data and add it to the file -- MSDEV will ignore it.
-            pdata = pickle.dumps(self.configs,1)
+            pdata = pickle.dumps(self.configs,PICKLE_PROTOCOL)
             pdata = base64.encodestring(pdata)
             self.file.write('<!-- SCons Data:\n' + pdata + '\n')
-            pdata = pickle.dumps(self.sources,1)
+            pdata = pickle.dumps(self.sources,PICKLE_PROTOCOL)
             pdata = base64.encodestring(pdata)
             self.file.write(pdata + '-->\n')
 
@@ -1606,7 +1607,7 @@ class _GenerateV7DSW(_DSWGenerator):
                             '\tEndGlobalSection\n')
         self.file.write('EndGlobal\n')
         if self.nokeep == 0:
-            pdata = pickle.dumps(self.configs,1)
+            pdata = pickle.dumps(self.configs,PICKLE_PROTOCOL)
             pdata = base64.encodestring(pdata)
             self.file.write(pdata + '\n')
 
diff --git a/src/engine/SCons/compat/__init__.py b/src/engine/SCons/compat/__init__.py
index 6f20b733..9a911f7b 100644
--- a/src/engine/SCons/compat/__init__.py
+++ b/src/engine/SCons/compat/__init__.py
@@ -88,6 +88,11 @@ def rename_module(new, old):
 # In 3.x, 'pickle' automatically loads the fast version if available.
 rename_module('pickle', 'cPickle')
 
+# Default pickle protocol. Higher protocols are more efficient/featureful
+# but incompatible with older Python versions. On Python 2.7 this is 2.
+# Negative numbers choose the highest available protocol.
+PICKLE_PROTOCOL=-1
+
 # TODO: FIXME
 # In 3.x, 'profile' automatically loads the fast version if available.
 rename_module('profile', 'cProfile')
diff --git a/src/engine/SCons/dblite.py b/src/engine/SCons/dblite.py
index b12d320a..c32f4946 100644
--- a/src/engine/SCons/dblite.py
+++ b/src/engine/SCons/dblite.py
@@ -4,6 +4,8 @@ from __future__ import print_function
 
 import SCons.compat
 
+from SCons.compat import PICKLE_PROTOCOL
+
 import os
 import pickle
 import shutil
@@ -119,7 +121,7 @@ class dblite(object):
   def sync(self):
     self._check_writable()
     f = self._open(self._tmp_name, "wb", self._mode)
-    self._pickle_dump(self._dict, f, 1)
+    self._pickle_dump(self._dict, f, PICKLE_PROTOCOL)
     f.close()
     # Windows doesn't allow renaming if the file exists, so unlink
     # it first, chmod'ing it to make sure we can do so.  On UNIX, we