jinja2: fix display of source in traceback

CHANGES.txt

+2.7 (2015-05-18)
+================
+
+* jinja2: fix display of source in traceback when there is an error in the
+  root template (or in instance parameters).
+
 2.6 (2014-11-26)
 ================
 

setup.py

 from setuptools import setup, find_packages
 import os
 
-version = '2.6'
+version = '2.7'
 name = 'slapos.recipe.template'
 long_description = open("README.txt").read() + "\n" + \
     open(os.path.join('slapos', 'recipe',

slapos/recipe/template/jinja2_template.py

@@ -134,14 +134,13 @@ LOADER_TYPE_DICT = {
 
 class Recipe(object):
     mode = 0777 # BBB: 0666 may have been a better default value
-    loader = None
     umask = None
 
     def __init__(self, buildout, name, options):
         template = options['template']
         if template.startswith('inline:'):
-            template = template[7:].lstrip('\r\n')
-            self.get_template = lambda: template
+            source = template[7:].lstrip('\r\n')
+            template = '<inline>'
         else:
             template = zc.buildout.download.Download(
                 buildout['buildout'],
@@ -150,7 +149,7 @@ class Recipe(object):
                 template,
                 md5sum=options.get('md5sum'),
             )[0]
-            self.get_template = lambda: open(template).read()
+            source = open(template).read()
         import_delimiter = options.get('import-delimiter',
             DEFAULT_IMPORT_DELIMITER)
         import_dict = {}
@@ -167,10 +166,12 @@ class Recipe(object):
                 import_delimiter,
             )
         if import_dict:
-            self.loader = RelaxedPrefixLoader(import_dict,
+            loader = RelaxedPrefixLoader(import_dict,
                 delimiter=import_delimiter)
+        else:
+            loader = None
         self.rendered = options['rendered']
-        self.extension_list = [x for x in (y.strip()
+        extension_list = [x for x in (y.strip()
             for y in options.get('extensions', '').split()) if x]
         self.context = context = DEFAULT_CONTEXT.copy()
         if _buildout_safe_dumps is not None:
@@ -191,6 +192,14 @@ class Recipe(object):
         umask_value = options.get('umask')
         if umask_value:
             self.umask = int(umask_value, 8)
+        env = Environment(
+            extensions=extension_list,
+            undefined=StrictUndefined,
+            loader=loader)
+        # For overriding from_string method of jinja2
+        self.template = env.template_class.from_code(env,
+            env.compile(source, filename=template),
+            env.make_globals(None), None)
 
     def install(self):
         # Unlink any existing file, so umask is always applied.
@@ -208,17 +217,7 @@ class Recipe(object):
             with os.fdopen(os.open(self.rendered,
                   os.O_CREAT | os.O_EXCL | os.O_WRONLY,
                   self.mode), 'w') as out:
-                out.write(
-                    Environment(
-                        extensions=self.extension_list,
-                        undefined=StrictUndefined,
-                        loader=self.loader,
-                    ).from_string(
-                        self.get_template(),
-                    ).render(
-                        **self.context
-                    )
-                )
+                out.write(self.template.render(**self.context))
         return self.rendered
 
     update = install