Introduce regex backend shim with opt-in feature flag

pyproject.toml

@@ -52,6 +52,7 @@ dependencies = [
 	"mdx-gh-links==0.4",
 	"l2m4m==1.0.4",
 	"pymdown-extensions==10.17.1",
+	"regex>=2026.4.4",
 ]
 
 [project.urls]

source/IAccessibleHandler/__init__.py

@@ -11,7 +11,7 @@
 # should be used to export it.
 from .types import RelationType  # noqa: F401
 
-import re
+import _regex as re
 import struct
 from typing import (
 	Optional,

source/NVDAObjects/IAccessible/__init__.py

@@ -23,7 +23,7 @@
 import comtypes.client
 import ctypes
 import os
-import re
+import _regex as re
 import sys
 import itertools
 import importlib

source/NVDAObjects/IAccessible/msOffice.py

@@ -10,7 +10,7 @@
 import winUser
 from . import IAccessible, getNVDAObjectFromEvent
 import eventHandler
-import re
+import _regex as re
 
 """Miscellaneous support for Microsoft Office applications.
 """

source/NVDAObjects/JAB/__init__.py

@@ -4,7 +4,7 @@
 # See the file COPYING for more details.
 
 import ctypes
-import re
+import _regex as re
 from typing import (
 	Any,
 )

source/NVDAObjects/UIA/excel.py

@@ -28,7 +28,7 @@
 import ui
 from logHandler import log
 from . import UIA
-import re
+import _regex as re
 
 
 class ExcelCustomProperties:

source/NVDAObjects/UIA/web.py

@@ -20,7 +20,7 @@
 from logHandler import log
 import controlTypes
 import cursorManager
-import re
+import _regex as re
 import aria
 import textInfos
 from UIAHandler.browseMode import (

source/NVDAObjects/window/__init__.py

@@ -3,7 +3,7 @@
 # This file is covered by the GNU General Public License.
 # See the file COPYING for more details.
 
-import re
+import _regex as re
 import ctypes
 import ctypes.wintypes
 from winBindings import user32

source/NVDAObjects/window/_msOfficeChart.py

@@ -11,7 +11,7 @@
 import controlTypes
 import colors
 import inputCore
-import re
+import _regex as re
 from logHandler import log
 import browseMode
 from scriptHandler import script

source/NVDAObjects/window/excel.py

@@ -21,7 +21,7 @@
 import wx
 import time
 import winsound
-import re
+import _regex as re
 import uuid
 import NVDAHelper
 import oleacc

source/_bridge/runtimes/synthDriverHost/main.pyw

@@ -12,6 +12,8 @@ import tempfile
 from winBindings.kernel32 import GetCurrentProcessId
 
 oldRecordFactory = logging.getLogRecordFactory()
+
+
 def recordFactory(*args, **kwargs):
 	record = oldRecordFactory(*args, **kwargs)
 	frame = inspect.currentframe()
@@ -27,6 +29,8 @@ def recordFactory(*args, **kwargs):
 		# co_qualname may be unavailable for some frames; in that case, keep the default record.name
 		pass
 	return record
+
+
 logging.setLogRecordFactory(recordFactory)
 
 exeName = os.path.splitext(os.path.basename(sys.executable))[0]
@@ -36,7 +40,7 @@ logging.basicConfig(
 	filename=logPath,
 	filemode="w",
 	level=logging.DEBUG,
-	format="%(levelname)s - %(module)s.%(name)s (%(asctime)s):\n%(message)s"
+	format="%(levelname)s - %(module)s.%(name)s (%(asctime)s):\n%(message)s",
 )
 log = logging.getLogger(exeName)
 # No comtypes debug logging
@@ -46,6 +50,7 @@ log.info(f"Logging initialized, log file: {logPath}")
 try:
 	gettext.install("nvda", names=["pgettext", "npgettext", "ngettext"])
 	import core
+
 	core.main()
 except Exception:
 	log.exception("Unhandled exception")

source/_regex.py

@@ -0,0 +1,49 @@
+# A part of NonVisual Desktop Access (NVDA)
+# This file is covered by the GNU General Public License.
+# See the file COPYING for more details.
+# Copyright (C) 2026 NV Access Limited
+
+"""Internal regex backend shim.
+
+Forwards attribute access to either stdlib :mod:`re` or the third-party :mod:`regex`
+module. The backend is chosen once by :func:`initialize` from the ``regexBackend``
+feature flag in user config and is then frozen for the lifetime of the process.
+Changes to the setting therefore require an NVDA restart.
+
+Intended usage::
+
+	import _regex as re
+
+	pattern = re.compile(r"\\w+", re.IGNORECASE)
+
+Before :func:`initialize` runs (early bootstrap, unit tests outside startup),
+attribute access falls back to stdlib :mod:`re`.
+"""
+
+import re as _re
+
+
+_backend = _re
+
+
+def initialize() -> None:
+	"""Resolve the regex backend from user config and freeze it for this process.
+
+	Call once after :func:`config.initialize`. Subsequent calls are ignored.
+	"""
+	global _backend
+	if _backend is not _re:
+		return
+	import config
+	from config.featureFlagEnums import RegexBackendFlag
+
+	if config.conf["featureFlag"]["regexBackend"].calculated() != RegexBackendFlag.REGEX:
+		return
+	import regex
+
+	regex.DEFAULT_VERSION = regex.VERSION1
+	_backend = regex
+
+
+def __getattr__(name: str):
+	return getattr(_backend, name)

source/addonAPIVersion.py

@@ -5,7 +5,7 @@
 
 
 import buildVersion
-import re
+import _regex as re
 
 
 """

source/appModules/code.py

@@ -8,7 +8,7 @@
 import api
 import appModuleHandler
 import controlTypes
-import re
+import _regex as re
 from collections import deque
 from logHandler import log
 from NVDAObjects.behaviors import EditableTextBase

source/appModules/foobar2000.py

@@ -5,7 +5,7 @@
 # See the file COPYING for more details.
 
 from datetime import datetime
-import re
+import _regex as re
 from typing import (
 	Dict,
 	NamedTuple,

source/appModules/lync.py

@@ -10,7 +10,7 @@
 import appModuleHandler
 from logHandler import log
 
-import re
+import _regex as re
 
 
 class NetUIRicherLabel(UIA):

source/appModules/securecrt.py

@@ -6,7 +6,7 @@
 
 """App module for SecureCRT"""
 
-import re
+import _regex as re
 import oleacc
 from NVDAObjects.behaviors import Terminal
 from NVDAObjects.window import DisplayModelEditableText, DisplayModelLiveText

source/bdDetect.py

@@ -31,7 +31,7 @@
 import config
 import appModuleHandler
 from baseObject import AutoPropertyObject
-import re
+import _regex as re
 from winAPI import messageWindow
 import extensionPoints
 from logHandler import log

source/braille.py

@@ -60,7 +60,7 @@
 import brailleDisplayDrivers
 import inputCore
 import brailleTables
-import re
+import _regex as re
 import scriptHandler
 import collections
 import extensionPoints

source/brailleDisplayDrivers/eurobraille/driver.py

@@ -5,7 +5,7 @@
 
 from collections import defaultdict
 from typing import Dict, Any, List, Union
-import re
+import _regex as re
 
 from io import BytesIO
 import serial

source/brailleDisplayDrivers/seikantk.py

@@ -8,7 +8,7 @@
 see www.seika-braille.com for more details
 """
 
-import re
+import _regex as re
 from io import BytesIO
 import typing
 from typing import Dict, List, Optional, Set

source/browseMode.py

@@ -12,7 +12,7 @@
 import winsound
 import time
 import weakref
-import re
+import _regex as re
 from comtypes import COMError
 
 import wx

source/characterProcessing.py

@@ -12,7 +12,7 @@
 import os
 import codecs
 import collections
-import re
+import _regex as re
 from typing import (
 	Callable,
 	Dict,

source/colors.py

@@ -6,7 +6,7 @@
 from collections import namedtuple
 import colorsys
 from ctypes.wintypes import COLORREF
-import re
+import _regex as re
 from functools import lru_cache
 from typing import Union
 

source/config/configSpec.py

@@ -356,6 +356,7 @@
 	cancelExpiredFocusSpeech = integer(0, 2, default=0)
 	# 0: Only in test versions, 1: Yes, 2: No
 	playErrorSound = integer(0, 2, default=0)
+	regexBackend = featureFlag(optionsEnum="RegexBackendFlag", behaviorOfDefault="RE")
 
 [addonStore]
 	automaticUpdates = option("notify", "update", "disabled", default="notify")

source/config/featureFlagEnums.py

@@ -139,6 +139,23 @@ def _displayStringLabels(self) -> dict["FontFormattingBrailleModeFlag", str]:
 		}
 
 
+class RegexBackendFlag(DisplayStringEnum):
+	"""Feature flag for selecting the regular expression backend."""
+
+	DEFAULT = enum.auto()
+	RE = enum.auto()
+	REGEX = enum.auto()
+
+	@property
+	def _displayStringLabels(self) -> dict["RegexBackendFlag", str]:
+		return {
+			# Translators: Label for the regex backend feature flag option using stdlib re.
+			RegexBackendFlag.RE: _("Python re"),
+			# Translators: Label for the regex backend feature flag option using the regex module.
+			RegexBackendFlag.REGEX: _("regex"),
+		}
+
+
 def getAvailableEnums() -> typing.Generator[typing.Tuple[str, FlagValueEnum], None, None]:
 	for name, value in globals().items():
 		if (

source/controlTypes/formatFields.py

@@ -3,7 +3,7 @@
 # See the file COPYING for more details.
 # Copyright (C) 2021-2023 NV Access Limited, Cyrille Bougot
 
-import re
+import _regex as re
 from typing import Dict
 
 from logHandler import log

source/core.py

@@ -712,6 +712,9 @@ def main():
 	import config
 
 	config.initialize()
+	import _regex
+
+	_regex.initialize()
 	if config.conf["development"]["enableScratchpadDir"]:
 		log.info("Developer Scratchpad mode enabled")
 	if languageHandler.isLanguageForced():

source/documentNavigation/sentenceHelper.py

@@ -4,7 +4,7 @@
 # This file may be used under the terms of the GNU General Public License, version 2 or later.
 # For more details see: https://www.gnu.org/licenses/gpl-2.0.html
 
-import re
+import _regex as re
 from typing import Optional
 
 WESTERN_TERMINATORS = "[.?!](?: |\r|\n|$)+"

source/gui/inputGestures.py

@@ -8,7 +8,7 @@
 # See the file COPYING for more details.
 
 import itertools
-import re
+import _regex as re
 from typing import Tuple, Union, Dict
 
 import wx