Do not use proxy for Function.prototype.toString

Fixes #685

lib/extension.js

@@ -144,20 +144,18 @@
 	const changedToStrings = new WeakMap();
 	scope.createProxyFunction = function createProxyFunction(window, original, replacement){
 		if (!changedToStrings.get(window)){
-			changedToStrings.set(window, true);
 			const functionPrototype = scope.getWrapped(window).Function.prototype;
-			const toString = functionPrototype.toString;
+			const originalToString = functionPrototype.toString;
+			changedToStrings.set(window, originalToString);
+			const alteredToString = scope.exportFunctionWithName(function toString(){
+				return proxies.get(this) || originalToString.call(this);
+			}, window, "toString");
+			proxies.set(alteredToString, originalToString.call(originalToString));
 			scope.changeProperty(window, "toString", {
 				object: functionPrototype,
 				name: "toString",
 				type: "value",
-				changed: scope.createProxyFunction(
-					window,
-					toString,
-					function(){
-						return proxies.get(this) || toString.call(this);
-					}
-				)
+				changed: alteredToString
 			});
 		}
 		const handler = scope.getWrapped(window).Object.create(null);
@@ -177,7 +175,7 @@
 			}
 		}, window, "");
 		const proxy = new window.Proxy(original, handler);
-		proxies.set(proxy, original.toString());
+		proxies.set(proxy, changedToStrings.get(window).call(original));
 		return scope.getWrapped(proxy);
 	};
 

releaseNotes.txt

@@ -1,6 +1,7 @@
 Version 1.10:
 	changes:
 		- added eBay and facebook.com to the convenience preset
+		- do not use proxy for Function.prototype.toString (causes weird problems sometimes)
 
 	new features:
 		- added setting showPresetsOnInstallation to be able to not show the presets page upon installation

test/detectionTest.js

@@ -181,6 +181,16 @@ addTest("toString modified", function(log){
 			configurable: true
 		},
 		log
+	) | checkPropertyDescriptor(
+		Function.prototype,
+		"toString",
+		{
+			value: function toString(){},
+			writable: true,
+			enumerable: false,
+			configurable: true
+		},
+		log
 	);
 });
 addTest("function name", function(log){