Change environment cache key construction

Changing from a tuple of the loader ID and template name to a weakref
to the loader and the template name should avoid situations whereby
the loader has changed, yet the cached templates are returned. This
would occur if the id of the new loader matches the old. A weakref is
preferred over a direct reference so that the loader can be garbaged
collected.

diff --git a/jinja2/environment.py b/jinja2/environment.py
index 67d05dd976db99bde8b9b54dcd1d9b034624cb5e..db51e941b511e954f73c1d321c1b3bda7919386c 100644 (file)
--- a/jinja2/environment.py
+++ b/jinja2/environment.py
@@ -10,6 +10,7 @@
 """
 import os
 import sys
+import weakref
 from functools import reduce, partial
 from jinja2 import nodes
 from jinja2.defaults import BLOCK_START_STRING, \
@@ -769,7 +770,7 @@ class Environment(object):
     def _load_template(self, name, globals):
         if self.loader is None:
             raise TypeError('no loader for this environment specified')
-        cache_key = (id(self.loader), name)
+        cache_key = (weakref.ref(self.loader), name)
         if self.cache is not None:
             template = self.cache.get(cache_key)
             if template is not None and (not self.auto_reload or

diff --git a/tests/test_loader.py b/tests/test_loader.py
index 6b9d9bb4f4123538fabce08573bb9ed8ff783e1d..b916b911b9dda968d25a7e9919cb6b0421f64c5d 100644 (file)
--- a/tests/test_loader.py
+++ b/tests/test_loader.py
@@ -13,6 +13,7 @@ import sys
 import tempfile
 import shutil
 import pytest
+import weakref
 
 from jinja2 import Environment, loaders
 from jinja2._compat import PYPY, PY2
@@ -92,9 +93,10 @@ class TestLoaders():
         assert t2 is env.get_template('two')
         assert t1 is env.get_template('one')
         t3 = env.get_template('three')
-        assert (id(loader), 'one') in env.cache
-        assert (id(loader), 'two') not in env.cache
-        assert (id(loader), 'three') in env.cache
+        loader_ref = weakref.ref(loader)
+        assert (loader_ref, 'one') in env.cache
+        assert (loader_ref, 'two') not in env.cache
+        assert (loader_ref, 'three') in env.cache
 
     def test_cache_loader_change(self):
         loader1 = loaders.DictLoader({'foo': 'one'})