From 51db6c97e0b0d982322875ef4a5eb1d32f359dd2 Mon Sep 17 00:00:00 2001
From: Armin Ronacher <armin.ronacher@active-4.com>
Date: Tue, 11 Jan 2011 20:53:42 +0100
Subject: [PATCH] No longer segfault on new versions.  This fixes #4

---
 CHANGES           |  7 +++++++
 jinja2/bccache.py | 13 +++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/CHANGES b/CHANGES
index b06192c..7815a6d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -17,6 +17,13 @@ Version 2.6
   of attributes.
 - scoped blocks not properly treat toplevel assignments and imports.
   Previously an import suddenly "disappeared" in a scoped block.
+- automatically detect newer Python interpreter versions before loading code
+  from bytecode caches to prevent segfaults on invalid opcodes.  The segfault
+  in earlier Jinja2 versions here was not a Jinja2 bug but a limitation in
+  the underlying Python interpreter.  If you notice Jinja2 segfaulting in
+  earlier versions after an upgrade of the Python interpreter you don't have
+  to upgrade, it's enough to flush the bytecode cache.  This just no longer
+  makes this necessary, Jinja2 will automatically detect these cases now.
 
 Version 2.5.5
 -------------
diff --git a/jinja2/bccache.py b/jinja2/bccache.py
index 1e2236c..0f7f566 100644
--- a/jinja2/bccache.py
+++ b/jinja2/bccache.py
@@ -15,6 +15,7 @@
     :license: BSD.
 """
 from os import path, listdir
+import sys
 import marshal
 import tempfile
 import cPickle as pickle
@@ -27,8 +28,16 @@ except ImportError:
 from jinja2.utils import open_if_exists
 
 
-bc_version = 1
-bc_magic = 'j2'.encode('ascii') + pickle.dumps(bc_version, 2)
+bc_version = 2
+
+# magic version used to only change with new jinja versions.  With 2.6
+# we change this to also take Python version changes into account.  The
+# reason for this is that Python tends to segfault if fed earlier bytecode
+# versions because someone thought it would be a good idea to reuse opcodes
+# or make Python incompatible with earlier versions.
+bc_magic = 'j2'.encode('ascii') + \
+    pickle.dumps(bc_version, 2) + \
+    pickle.dumps((sys.version_info[0] << 24) | sys.version_info[1])
 
 
 class Bucket(object):