From fa5deb6b44b61b3c501008797b08afcb5a1b9426 Mon Sep 17 00:00:00 2001
From: Mukesh <mukeshchugh5@gmail.com>
Date: Sun, 30 Dec 2018 12:02:28 +0530
Subject: [PATCH] More informative error for invalid values passed to
 `|richtext` (#4971)

Fixes #4958
---
 CHANGELOG.txt                                 | 1 +
 CONTRIBUTORS.rst                              | 1 +
 docs/releases/2.5.rst                         | 2 ++
 wagtail/core/templatetags/wagtailcore_tags.py | 5 ++++-
 wagtail/core/tests/tests.py                   | 8 ++++++++
 5 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index f2a271edd4..9cb19d1015 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -4,6 +4,7 @@ Changelog
 2.5 (xx.xx.xxxx) - IN DEVELOPMENT
 ~~~~~~~~~~~~~~~~
 
+ * Added more informative error message when `|richtext` filter is applied to a non-string value (mukesh5)
  * Fix: Set `SERVER_PORT` to 443 in `Page.dummy_request()` for HTTPS sites (Sergey Fedoseev)
  * Fix: Validation error messages in `InlinePanel` no longer count towards `max_num` when disabling the 'add' button (Todd Dembrey, Thibaud Colas)
 
diff --git a/CONTRIBUTORS.rst b/CONTRIBUTORS.rst
index 7882c8d3b2..b2c6228a0f 100644
--- a/CONTRIBUTORS.rst
+++ b/CONTRIBUTORS.rst
@@ -337,6 +337,7 @@ Contributors
 * Nick Travis
 * Maylon Pedroso
 * Thijs Walcarius
+* mukesh5
 
 Translators
 ===========
diff --git a/docs/releases/2.5.rst b/docs/releases/2.5.rst
index 9363d129f2..1cda5d3b5c 100644
--- a/docs/releases/2.5.rst
+++ b/docs/releases/2.5.rst
@@ -14,6 +14,8 @@ What's new
 Other features
 ~~~~~~~~~~~~~~
 
+ * Added more informative error message when ``|richtext`` filter is applied to a non-string value (mukesh5)
+
 
 Bug fixes
 ~~~~~~~~~
diff --git a/wagtail/core/templatetags/wagtailcore_tags.py b/wagtail/core/templatetags/wagtailcore_tags.py
index b14de2345b..dda1cf62d8 100644
--- a/wagtail/core/templatetags/wagtailcore_tags.py
+++ b/wagtail/core/templatetags/wagtailcore_tags.py
@@ -87,7 +87,10 @@ def richtext(value):
     elif value is None:
         html = ''
     else:
-        html = expand_db_html(value)
+        if isinstance(value, str):
+            html = expand_db_html(value)
+        else:
+            raise TypeError("'richtext' template filter received an invalid value; expected string, got {}.".format(type(value)))
 
     return mark_safe('<div class="rich-text">' + html + '</div>')
 
diff --git a/wagtail/core/tests/tests.py b/wagtail/core/tests/tests.py
index e70eacb97c..61507fe895 100644
--- a/wagtail/core/tests/tests.py
+++ b/wagtail/core/tests/tests.py
@@ -261,3 +261,11 @@ class TestRichtextTag(TestCase):
     def test_call_with_none(self):
         result = richtext(None)
         self.assertEqual(result, '<div class="rich-text"></div>')
+
+    def test_call_with_invalid_value(self):
+        with self.assertRaisesRegex(TypeError, "'richtext' template filter received an invalid value"):
+            richtext(42)
+
+    def test_call_with_bytes(self):
+        with self.assertRaisesRegex(TypeError, "'richtext' template filter received an invalid value"):
+            richtext(b"Hello world!")