userchrome.js prevent firefox start normally

[orency]

With recent firefox version(138+ may be earlier),used userchrome.js will prevent firefox start normally.
The firefox will pop up a message box that shows error 'Failed to read the configuration file. Please contact your system administrator'.
And Not any function provided by userchrome.js works well after I close the message box,it's totally broken.
After I delete the userchrome.js and enableuserchrome.js,firefox can start normally again.

[iG8R]

config.js (c:\Program Files\Mozilla Firefox\config.js) should be as follows:

//https://forum.mozilla-russia.org/viewtopic.php?pid=808453#p808453
//
try {(jsval => {
	var dbg, gref, genv = func => {
		var sandbox = new Cu.Sandbox(g, {freshCompartment: true});
		Cc["@mozilla.org/jsdebugger;1"].createInstance(Ci.IJSDebugger).addClass(sandbox);
		(dbg = new sandbox.Debugger()).addDebuggee(g);
		gref = dbg.makeGlobalObjectReference(g);
		return (genv = func => func && gref.makeDebuggeeValue(func).environment)(func);
	}
	var g = Cu.getGlobalForObject(jsval), o = g.Object, {freeze} = o, disleg;

	var lexp = () => lockPref("extensions.experiments.enabled", true);
	var MRS = "MOZ_REQUIRE_SIGNING", AC = "AppConstants", uac = `resource://gre/modules/${AC}.`;

	if (o.isFrozen(o)) { // Fx 102.0b7+
		lexp(); disleg = true; genv();

		dbg.onEnterFrame = frame => {
			var {script} = frame;
			try {if (!script.url.startsWith(uac)) return;} catch {return;}
			dbg.onEnterFrame = undefined;

			if (script.isModule) { // ESM, Fx 108+
				var env = frame.environment;
				frame.onPop = () => env.setVariable(AC, gref.makeDebuggeeValue(freeze(
					o.assign(new o(), env.getVariable(AC).unsafeDereference(), {[MRS]: false})
				)));
			}
			else { // JSM
				var nsvo = frame.this.unsafeDereference();
				nsvo.Object = {freeze(ac) {
					ac[MRS] = false;
					delete nsvo.Object;
					return freeze(ac);
				}};
			}
		}
	}
	else o.freeze = obj => {
		if (!Components.stack.caller.filename.startsWith(uac)) return freeze(obj);
		obj[MRS] = false;

		if ((disleg = "MOZ_ALLOW_ADDON_SIDELOAD" in obj)) lexp();
		else
			obj.MOZ_ALLOW_LEGACY_EXTENSIONS = true,
			lockPref("extensions.legacy.enabled", true);

		return (o.freeze = freeze)(obj);
	}
	lockPref("xpinstall.signatures.required", false);
	lockPref("extensions.langpacks.signatures.required", false);

	var useDbg = true, xpii = "resource://gre/modules/addons/XPIInstall.";
	if (Ci.nsINativeFileWatcherService) { // Fx < 100
		jsval = Cu.import(xpii + "jsm", {});
		var shouldVerify = jsval.shouldVerifySignedState;
		if (shouldVerify.length == 1)
			useDbg = false,
			jsval.shouldVerifySignedState = addon => !addon.id && shouldVerify(addon);
	}
	if (useDbg) { // Fx 99+
		try {var exp = ChromeUtils.importESModule(xpii + "sys.mjs");}
		catch {exp = g.ChromeUtils.import(xpii + "jsm");}
		jsval = o.assign({}, exp);

		var env = genv(jsval.XPIInstall.installTemporaryAddon);
		var ref = name => {try {return env.find(name).getVariable(name).unsafeDereference();} catch {}}
		jsval.XPIDatabase = (ref("XPIExports") || ref("lazy") || {}).XPIDatabase || ref("XPIDatabase");

		var proto = ref("Package").prototype;
		var verify = proto.verifySignedState;
		proto.verifySignedState = function(id) {
			return id ? {cert: null, signedState: undefined} : verify.apply(this, arguments);
		}
		dbg.removeAllDebuggees();
	}
	if (disleg) jsval.XPIDatabase.isDisabledLegacy = () => false;
})(
	"permitCPOWsInScope" in Cu ? Cu.import("resource://gre/modules/WebRequestCommon.jsm", {}) : Cu
);}
catch(ex) {Cu.reportError(ex);}

[orency]

config.js (c:\Program Files\Mozilla Firefox\config.js) should be as follows:

With the content you provided,firefox won't pop up error box any more when starting.
Howerer ,*.uc.js such as OneClickSearch.uc.js within /profiles folder/chrome/ that still not work.
I have done anything i can do refer to https://github.com/Aris-t2/CustomJSforFx andhttps://github.com/xiaoxiaoflood/firefox-scripts
How can I do now?

[iG8R]

Try the file that is use myself.

config.js.txt

[orency]

Try the file that is use myself.

I have tried the file you provided,but still nothing *.uc.js have effect.
Does anything else I forgotten should do?

[iG8R]

Create a new profile with nothing but config.js and its associated files.
Then, try using a generic userchrome.js first, and using devtools, examine what the console shows. If everything is okay with it, use your own, also studying the changes in the console.

[orency]

Thank you for your tutorial.
I have found the reasons :
Firefox removed XPCOMUtils.defineLazyModuleGetters and converted most jsm to sys.mjs since 120.
Just need to change the follow block in OneClickSearch.uc.js can make it work again.

 init: function() {
    ChromeUtils.defineESModuleGetters(this, {
      UrlbarSearchOneOffs: "resource:///modules/UrlbarSearchOneOffs.sys.mjs",
      UrlbarUtils: "resource:///modules/UrlbarUtils.sys.mjs",
    });

maybe someone can push a commit to notify the author?

[iG8R]

Good to hear the issue is resolved.