From 313c3d1aa14d80922003f841c257ec4e153f8653 Mon Sep 17 00:00:00 2001
From: cammil <cammil@MacBook-Pro.local>
Date: Fri, 7 May 2021 21:49:07 +0100
Subject: [PATCH] Fixed #28935 -- Fixed display of errors in extended blocks.

Get the template that caused the exception and get the
exception info from that template, using the node that
caused the exception.
---
 django/template/base.py                         | 13 +++++++++++--
 .../templates/test_extends_block_error.html     |  2 ++
 .../test_extends_block_error_parent.html        |  1 +
 tests/template_tests/tests.py                   | 17 ++++++++++++++++-
 4 files changed, 30 insertions(+), 3 deletions(-)
 create mode 100644 tests/template_tests/templates/test_extends_block_error.html
 create mode 100644 tests/template_tests/templates/test_extends_block_error_parent.html

diff --git a/django/template/base.py b/django/template/base.py
index 4972bd7c58..b47154d88a 100644
--- a/django/template/base.py
+++ b/django/template/base.py
@@ -926,8 +926,17 @@ class Node:
         try:
             return self.render(context)
         except Exception as e:
-            if context.template.engine.debug and not hasattr(e, 'template_debug'):
-                e.template_debug = context.render_context.template.get_exception_info(e, self.token)
+            if context.template.engine.debug:
+                # Store the actual node that caused the exception.
+                if not hasattr(e, '_culprit_node'):
+                    e._culprit_node = self
+                if (
+                    not hasattr(e, 'template_debug') and
+                    context.render_context.template.origin == e._culprit_node.origin
+                ):
+                    e.template_debug = context.render_context.template.get_exception_info(
+                        e, e._culprit_node.token,
+                    )
             raise
 
     def __iter__(self):
diff --git a/tests/template_tests/templates/test_extends_block_error.html b/tests/template_tests/templates/test_extends_block_error.html
new file mode 100644
index 0000000000..c4733747a2
--- /dev/null
+++ b/tests/template_tests/templates/test_extends_block_error.html
@@ -0,0 +1,2 @@
+{% extends "test_extends_block_error_parent.html" %}
+{% block content %}{% include "missing.html" %}{% endblock %}
diff --git a/tests/template_tests/templates/test_extends_block_error_parent.html b/tests/template_tests/templates/test_extends_block_error_parent.html
new file mode 100644
index 0000000000..cb0dbe444b
--- /dev/null
+++ b/tests/template_tests/templates/test_extends_block_error_parent.html
@@ -0,0 +1 @@
+{% block content %}{% endblock %}
diff --git a/tests/template_tests/tests.py b/tests/template_tests/tests.py
index a8f089c351..5ea026723e 100644
--- a/tests/template_tests/tests.py
+++ b/tests/template_tests/tests.py
@@ -1,11 +1,14 @@
 import sys
 
 from django.contrib.auth.models import Group
-from django.template import Context, Engine, TemplateSyntaxError
+from django.template import (
+    Context, Engine, TemplateDoesNotExist, TemplateSyntaxError,
+)
 from django.template.base import UNKNOWN_SOURCE
 from django.test import SimpleTestCase, override_settings
 from django.urls import NoReverseMatch
 from django.utils import translation
+from django.utils.html import escape
 
 
 class TemplateTests(SimpleTestCase):
@@ -134,6 +137,18 @@ class TemplateTests(SimpleTestCase):
             t.render(Context())
         self.assertEqual(e.exception.template_debug['during'], '{% badtag %}')
 
+    def test_render_tag_error_in_extended_block(self):
+        """Errors in extended block are displayed correctly."""
+        e = Engine(app_dirs=True, debug=True)
+        template = e.get_template('test_extends_block_error.html')
+        context = Context()
+        with self.assertRaises(TemplateDoesNotExist) as cm:
+            template.render(context)
+        self.assertEqual(
+            cm.exception.template_debug['during'],
+            escape('{% include "missing.html" %}'),
+        )
+
     def test_super_errors(self):
         """
         #18169 -- NoReverseMatch should not be silence in block.super.