Make sure that we don't try to double-encode params using the traditional style. Fixes #6041.

src/ajax.js

@@ -624,7 +624,7 @@ jQuery.extend({
 			// If traditional, encode the "old" way (the way 1.3.2 or older
 			// did it), otherwise encode params recursively.
 			for ( var prefix in a ) {
-				buildParams( prefix, a[prefix] );
+				buildParams( traditional ? prefix : prefix.replace(/[\[\]]/g, ""), a[prefix] );
 			}
 		}
 

test/unit/ajax.js

@@ -351,9 +351,9 @@ test("serialize()", function() {
 });
 
 test("jQuery.param()", function() {
-	expect(18);
+	expect(19);
 	
-  equals( !jQuery.ajaxSettings.traditional, true, "traditional flag, falsy by default" );
+	equals( !jQuery.ajaxSettings.traditional, true, "traditional flag, falsy by default" );
   
 	var params = {foo:"bar", baz:42, quux:"All your base are belong to us"};
 	equals( jQuery.param(params), "foo=bar&baz=42&quux=All+your+base+are+belong+to+us", "simple" );
@@ -378,6 +378,8 @@ test("jQuery.param()", function() {
 	
 	params = { a:[1,2], b:{ c:3, d:[4,5], e:{ x:[6], y:7, z:[8,9] }, f:true, g:false, h:undefined }, i:[10,11], j:true, k:false, l:[undefined,0], m:"cowboy hat?" };
 	equals( jQuery.param(params,true), "a=1&a=2&b=%5Bobject+Object%5D&i=10&i=11&j=true&k=false&l=undefined&l=0&m=cowboy+hat%3F", "huge structure, forced traditional" );
+
+	equals( decodeURIComponent( jQuery.param({ "test[]": [0, 1, 2] }) ), "test[]=0&test[]=1&test[]=2", "Make sure params are double-encoded." );
 	
 	jQuery.ajaxSetup({ traditional: true });