[1.11.x] Fixed #27956 -- Fixed display of errors in an {% extends %} child.

Thanks Ling-Xiao Yang for the report and test, and
Preston Timmons for the fix.

Backport of e643ba8bcf0b1da517cbab689ac157ee031202a3 from master

2 files changed, 7 insertions, 4 deletions

diff --git a/django/template/context.py b/django/template/context.py
index 166f60fe75..7f0826c644 100644
--- a/django/template/context.py
+++ b/django/template/context.py
@@ -215,15 +215,17 @@ class RenderContext(BaseContext):
         return self.dicts[-1][key]
 
     @contextmanager
-    def push_state(self, template):
+    def push_state(self, template, isolated_context=True):
         initial = self.template
         self.template = template
-        self.push()
+        if isolated_context:
+            self.push()
         try:
             yield
         finally:
             self.template = initial
-            self.pop()
+            if isolated_context:
+                self.pop()
 
 
 class RequestContext(Context):
diff --git a/django/template/loader_tags.py b/django/template/loader_tags.py
index 4ff5ec4db5..020f2e412a 100644
--- a/django/template/loader_tags.py
+++ b/django/template/loader_tags.py
@@ -173,7 +173,8 @@ class ExtendsNode(Node):
 
         # Call Template._render explicitly so the parser context stays
         # the same.
-        return compiled_parent._render(context)
+        with context.render_context.push_state(compiled_parent, isolated_context=False):
+            return compiled_parent._render(context)
 
 
 class IncludeNode(Node):