From 61f1154f232c89d5e8d17ca56616e42e328db7eb Mon Sep 17 00:00:00 2001
From: Chris Sewell <chrisj_sewell@hotmail.com>
Date: Fri, 6 Aug 2021 05:50:01 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=91=8C=20IMPROVE:=20Fail=20gracefully=20o?=
 =?UTF-8?q?n=20non-dict=20front-matter=20(#409)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 myst_parser/docutils_renderer.py | 7 ++++++-
 myst_parser/sphinx_renderer.py   | 6 +++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/myst_parser/docutils_renderer.py b/myst_parser/docutils_renderer.py
index 1be2fda9..cfd75230 100644
--- a/myst_parser/docutils_renderer.py
+++ b/myst_parser/docutils_renderer.py
@@ -609,7 +609,12 @@ def render_front_matter(self, token: SyntaxTreeNode) -> None:
         if not isinstance(token.content, dict):
             try:
                 data = yaml.safe_load(token.content)
-            except (yaml.parser.ParserError, yaml.scanner.ScannerError) as error:
+                assert isinstance(data, dict), "not dict"
+            except (
+                AssertionError,
+                yaml.parser.ParserError,
+                yaml.scanner.ScannerError,
+            ) as error:
                 msg_node = self.reporter.error(
                     "Front matter block:\n" + str(error), line=position
                 )
diff --git a/myst_parser/sphinx_renderer.py b/myst_parser/sphinx_renderer.py
index 513eee6e..a2b7ebe5 100644
--- a/myst_parser/sphinx_renderer.py
+++ b/myst_parser/sphinx_renderer.py
@@ -192,7 +192,11 @@ class MockSphinx(Sphinx):
         def __init__(self, confoverrides=None, srcdir=None, raise_on_warning=False):
             self.extensions = {}
             self.registry = SphinxComponentRegistry()
-            self.html_themes = {}
+            try:
+                self.html_themes = {}
+            except AttributeError:
+                # changed to property in sphinx 4.1
+                pass
             self.events = EventManager(self)
 
             # logging