Warn about unknown command line arguments when starting NVDA

launcher/nvdaLauncher.nsi

@@ -90,7 +90,7 @@ file /R "${NVDADistDir}\"
 ${GetParameters} $0
 Banner::destroy
 exec:
-execWait "$PLUGINSDIR\app\nvda_noUIAccess.exe $0 -r --launcher" $1
+execWait "$PLUGINSDIR\app\nvda_noUIAccess.exe $0 --launcher" $1
 ;If exit code is 3 then execute again (restart)
 intcmp $1 3 exec +1
 SectionEnd

source/addonHandler/__init__.py

@@ -29,6 +29,7 @@
 import addonAPIVersion
 from . import addonVersionCheck
 from .addonVersionCheck import isAddonCompatible
+import extensionPoints
 import buildVersion
 
 
@@ -44,6 +45,12 @@
 _blockedAddons=set()
 
 
+# Allows add-ons to process additional command line arguments when NVDA starts.
+# Each handler is called with one keywod argument `cliArgument`
+# and should return `False` if it is not interested in it, `True` otherwise.
+isCLIParamKnown = extensionPoints.AccumulatingDecider(defaultDecision=False)
+
+
 class AddonsState(collections.UserDict):
 	"""Subclasses `collections.UserDict` to preserve backwards compatibility."""
 

source/core.py

@@ -8,7 +8,7 @@
 
 
 from dataclasses import dataclass
-from typing import Optional
+from typing import List, Optional
 import comtypes
 import sys
 import winVersion
@@ -56,7 +56,33 @@
 def doStartupDialogs():
 	import config
 	import gui
-	# Translators: The title of the dialog to tell users that there are erros in the configuration file.
+
+	def handleReplaceCLIArg(cliArgument: str) -> bool:
+		"""Since #9827 NVDA replaces a currently running instance
+		and therefore `--replace` command line argument is redundant and no longer supported.
+		However for backwards compatibility the desktop shortcut created by installer
+		still starts NVDA with the now redundant switch.
+		Its presence in command line arguments should not cause a warning on startup."""
+		return cliArgument in ("-r", "--replace")
+
+	addonHandler.isCLIParamKnown.register(handleReplaceCLIArg)
+	unknownCLIParams: List[str] = list()
+	for param in globalVars.unknownAppArgs:
+		isParamKnown = addonHandler.isCLIParamKnown.decide(cliArgument=param)
+		if not isParamKnown:
+			unknownCLIParams.append(param)
+	if unknownCLIParams:
+		import wx
+		gui.messageBox(
+			# Translators: Shown when NVDA has been started with unknown command line parameters.
+			_("The following command line parameters are unknown to NVDA: {params}").format(
+				params=", ".join(unknownCLIParams)
+			),
+			# Translators: Title of the dialog letting user know
+			# that command line parameters they provided are unknown.
+			_("Unknown command line parameters!"),
+			wx.OK | wx.ICON_ERROR
+		)
 	if config.conf.baseConfigError:
 		import wx
 		gui.messageBox(

source/extensionPoints/__init__.py

@@ -1,18 +1,18 @@
-#extensionPoints.py
-#A part of NonVisual Desktop Access (NVDA)
-#Copyright (C) 2017 NV Access Limited
-#This file is covered by the GNU General Public License.
-#See the file COPYING for more details.
+# A part of NonVisual Desktop Access (NVDA)
+# Copyright (C) 2017-2021 NV Access Limited, Joseph Lee, Łukasz Golonka
+# This file is covered by the GNU General Public License.
+# See the file COPYING for more details.
 
 """Framework to enable extensibility at specific points in the code.
 This allows interested parties to register to be notified when some action occurs
 or to modify a specific kind of data.
 For example, you might wish to notify about a configuration profile switch
 or allow modification of spoken messages before they are passed to the synthesizer.
-See the L{Action}, L{Filter}, L{Decider} classes.
+See the L{Action}, L{Filter}, L{Decider} and L{AccumulatingDecider} classes.
 """
 from logHandler import log
 from .util import HandlerRegistrar, callWithSupportedKwargs, BoundMethodWeakref
+from typing import Set
 
 
 class Action(HandlerRegistrar):
@@ -152,3 +152,59 @@ def decide(self, **kwargs):
 			if not decision:
 				return False
 		return True
+
+
+class AccumulatingDecider(HandlerRegistrar):
+	"""Allows interested parties to participate in deciding whether something
+	should be done.
+	In contrast with L{Decider} all handlers are executed and then results are returned.
+	For example, normally user should be warned about all command line parameters
+	which are unknown to NVDA, but this extension point can be used to pass each unknown parameter
+	to all add-ons since one of them may want to process some command line arguments.
+
+	First, a AccumulatingDecider is created with a default decision  :
+
+	>>> doSomething = AccumulatingDecider(defaultDecision=True)
+
+	Interested parties then register to participate in the decision, see
+	L{register} docstring for details of the type of handlers that can be
+	registered:
+
+	>>> def shouldDoSomething(someArg=None):
+	... 	return False
+	...
+	>>> doSomething.register(shouldDoSomething)
+
+	When the decision is to be made registered handlers are called and they return values are collected,
+	see L{util.callWithSupportedKwargs}
+	for how args passed to notify are mapped to the handler:
+
+	>>> doSomething.decide(someArg=42)
+	False
+
+	If there are no handlers or all handlers return defaultDecision,
+	the return value is the value of the default decision.
+	"""
+
+	def __init__(self, defaultDecision: bool) -> None:
+		super().__init__()
+		self.defaultDecision: bool = defaultDecision
+
+	def decide(self, **kwargs) -> bool:
+		"""Call handlers to make a decision.
+		Results returned from all handlers are collected
+		and if at least one handler returns value different than the one specifed as default it is returned.
+		If there are no handlers or all handlers return the default value, the default value is returned.
+		@param kwargs: Arguments to pass to the handlers.
+		@return: The decision.
+		"""
+		decisions: Set[bool] = set()
+		for handler in self.handlers:
+			try:
+				decisions.add(callWithSupportedKwargs(handler, **kwargs))
+			except Exception:
+				log.exception("Error running handler %r for %r" % (handler, self))
+				continue
+		if (not self.defaultDecision) in decisions:
+			return (not self.defaultDecision)
+		return self.defaultDecision

source/globalVars.py

@@ -61,7 +61,7 @@ class DefautAppArgs(argparse.Namespace):
 reviewPositionObj=None
 lastProgressValue=0
 appArgs = DefautAppArgs()
-appArgsExtra=None
+unknownAppArgs: typing.List[str] = []
 settingsRing = None
 speechDictionaryProcessing=True
 exitCode=0

source/nvda.pyw

@@ -188,7 +188,7 @@ parser.add_argument(
 # but that's far better than a major security hazzard.
 # If this option is provided, NVDA will not replace an already running instance (#10179) 
 parser.add_argument('--ease-of-access',action="store_true",dest='easeOfAccess',default=False,help="Started by Windows Ease of Access")
-(globalVars.appArgs,globalVars.appArgsExtra)=parser.parse_known_args()
+(globalVars.appArgs, globalVars.unknownAppArgs) = parser.parse_known_args()
 # Make any app args path values absolute
 # So as to not be affected by the current directory changing during process lifetime.
 pathAppArgs = [