Ticket #24577: 24577.diff

django/template/loader_tags.py

@@ -6 +6 @@
 from django.utils.deprecation import RemovedInDjango21Warning
 from django.utils.safestring import mark_safe
 
+from . import engines
 from .base import (
     Node, Template, TemplateSyntaxError, TextNode, Variable, token_kwargs,
 )
@@ -18 +19 @@
 logger = logging.getLogger('django.template')
 
 
+class DifferentTemplateEngineError(Exception):
+    pass
+
+
 class BlockContext:
     def __init__(self):
         # Dictionary of FIFO queues.
@@ -183 +188 @@
             # Use the base.Template of a backends.django.Template.
             elif hasattr(template, 'template'):
                 template = template.template
+
+            if context.template.engine != template.engine:
+                raise DifferentTemplateEngineError(
+                    'Included template %r is from engine %r but parent template '
+                    '%r is from engine %r. Including a template from a '
+                    'different engine is prohibited.' % (
+                        template.name,
+                        engines.get_name_from_engine(template.engine),
+                        context.template.name,
+                        engines.get_name_from_engine(context.template.engine),
+                    )
+                )
             values = {
                 name: var.resolve(context)
                 for name, var in self.extra_context.items()
@@ -191 +208 @@
                 return template.render(context.new(values))
             with context.push(**values):
                 return template.render(context)
+        except DifferentTemplateEngineError:
+            raise
         except Exception as e:
             if context.template.engine.debug:
                 raise

django/template/utils.py

@@ -87 +87 @@
     def all(self):
         return [self[alias] for alias in self]
 
+    def get_name_from_engine(self, engine):
+        try:
+            return next(e.name for e in self.all() if e.engine is engine)
+        except StopIteration:
+            return 'unnamed'
+
 
 @functools.lru_cache()
 def get_app_template_dirs(dirname):

tests/template_tests/syntax_tests/test_include.py

@@ -3 +3 @@
 from django.template import (
     Context, Engine, TemplateDoesNotExist, TemplateSyntaxError, loader,
 )
+from django.template.loader_tags import DifferentTemplateEngineError
 from django.test import SimpleTestCase, ignore_warnings
 from django.utils.deprecation import RemovedInDjango21Warning
 
@@ -282 +283 @@
         output = tmpl.render({'tmpl': loader.get_template('index.html')})
         self.assertEqual(output, 'index\n\n')
 
+    def test_include_from_other_engine(self):
+        engine = Engine()
+        ctx = Context({'tmpl': loader.get_template('index.html')})
+        outer_tmpl = engine.from_string('{% include tmpl %}')
+        msg = (
+            "Included template 'index.html' is from engine 'django' but parent "
+            "template None is from engine 'unnamed'. Including a template from "
+            "a different engine is prohibited."
+        )
+        with self.assertRaisesMessage(DifferentTemplateEngineError, msg):
+            outer_tmpl.render(ctx)
+
     def test_include_immediate_missing(self):
         """
         #16417 -- Include tags pointing to missing templates should not raise