From 39a45ad4073a4d8c3b7dfd64d22e8a88870dcc7c Mon Sep 17 00:00:00 2001
From: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Date: Sat, 12 Oct 2024 19:29:51 +0100
Subject: [PATCH] Expose ``ExtensionError`` in ``sphinx.util`` for backwards
 compatibility.

This will be removed in Sphinx 9, as exposing the exception
in ``sphinx.util`` was never intentional. ``ExtensionError``
has been part of ``sphinx.errors`` since v0.9.
---
 CHANGES.rst             | 6 ++++++
 sphinx/util/__init__.py | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/CHANGES.rst b/CHANGES.rst
index 1c5a45a7f26..0ab26a89cc2 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,6 +4,12 @@ Release 8.1.2 (in development)
 Bugs fixed
 ----------
 
+* #13012: Expose :exc:`sphinx.errors.ExtensionError` in ``sphinx.util``
+  for backwards compatibility.
+  This will be removed in Sphinx 9, as exposing the exception
+  in ``sphinx.util`` was never intentional.
+  :exc:`!ExtensionError` has been part of ``sphinx.errors`` since Sphinx 0.9.
+  Patch by Adam Turner.
 
 Release 8.1.1 (released Oct 11, 2024)
 =====================================
diff --git a/sphinx/util/__init__.py b/sphinx/util/__init__.py
index 07af8602079..73a66a9a60d 100644
--- a/sphinx/util/__init__.py
+++ b/sphinx/util/__init__.py
@@ -8,6 +8,7 @@
 import re
 from typing import Any
 
+from sphinx.errors import ExtensionError as _ExtensionError
 from sphinx.errors import FiletypeNotFoundError
 from sphinx.util import _files, _importer, logging
 from sphinx.util import index_entries as _index_entries
@@ -86,6 +87,7 @@ def _sha1(data: bytes = b'', **_kw: Any) -> hashlib._Hash:
         'sphinx.util.index_entries.split_into',
         (9, 0),
     ),
+    'ExtensionError': (_ExtensionError, 'sphinx.errors.ExtensionError', (9, 0)),
     'md5': (_md5, '', (9, 0)),
     'sha1': (_sha1, '', (9, 0)),
     'import_object': (_importer.import_object, '', (10, 0)),