Propagate context of returned deferred object in Deferred.then(). Fixes #13160.

2 files changed, 30 insertions, 17 deletions

diff --git a/src/deferred.js b/src/deferred.js
index d84206570..0efc05dc3 100644
--- a/src/deferred.js
+++ b/src/deferred.js
@@ -21,22 +21,19 @@ jQuery.extend({
 					return jQuery.Deferred(function( newDefer ) {
 						jQuery.each( tuples, function( i, tuple ) {
 							var action = tuple[ 0 ],
-								fn = fns[ i ];
+								fn = jQuery.isFunction( fns[ i ] ) && fns[ i ];
 							// deferred[ done | fail | progress ] for forwarding actions to newDefer
-							deferred[ tuple[1] ]( jQuery.isFunction( fn ) ?
-								function() {
-									var returned = fn.apply( this, arguments );
-									if ( returned && jQuery.isFunction( returned.promise ) ) {
-										returned.promise()
-											.done( newDefer.resolve )
-											.fail( newDefer.reject )
-											.progress( newDefer.notify );
-									} else {
-										newDefer[ action + "With" ]( this === promise ? newDefer.promise() : this, [ returned ] );
-									}
-								} :
-								newDefer[ action ]
-							);
+							deferred[ tuple[1] ](function() {
+								var returned = fn && fn.apply( this, arguments );
+								if ( returned && jQuery.isFunction( returned.promise ) ) {
+									returned.promise()
+										.done( newDefer.resolve )
+										.fail( newDefer.reject )
+										.progress( newDefer.notify );
+								} else {
+									newDefer[ action + "With" ]( this === promise ? newDefer.promise() : this, fn ? [ returned ] : arguments );
+								}
+							});
 						});
 						fns = null;
 					}).promise();
@@ -72,7 +69,7 @@ jQuery.extend({
 
 			// deferred[ resolve | reject | notify ]
 			deferred[ tuple[0] ] = function() {
-				deferred[ tuple[0] + "With" ]( promise, arguments );
+				deferred[ tuple[0] + "With" ]( this === deferred ? promise : this, arguments );
 				return this;
 			};
 			deferred[ tuple[0] + "With" ] = list.fireWith;
diff --git a/test/unit/deferred.js b/test/unit/deferred.js
index 86b0b3411..f9bc13a9c 100644
--- a/test/unit/deferred.js
+++ b/test/unit/deferred.js
@@ -273,7 +273,7 @@ test( "jQuery.Deferred.then - deferred (progress)", function() {
 
 test( "jQuery.Deferred.then - context", function() {
 
-	expect( 4 );
+	expect( 7 );
 
 	var context = {};
 
@@ -284,6 +284,12 @@ test( "jQuery.Deferred.then - context", function() {
 		strictEqual( value, 6, "proper value received" );
 	});
 
+	jQuery.Deferred().resolve().then(function() {
+		return jQuery.Deferred().resolveWith(context);
+	}).done(function() {
+		strictEqual( this, context, "custom context of returned deferred correctly propagated" );
+	});
+
 	var defer = jQuery.Deferred(),
 		piped = defer.then(function( value ) {
 			return value * 3;
@@ -295,6 +301,16 @@ test( "jQuery.Deferred.then - context", function() {
 		strictEqual( this, piped, "default context gets updated to latest promise in the chain" );
 		strictEqual( value, 6, "proper value received" );
 	});
+
+	var defer2 = jQuery.Deferred(),
+		piped2 = defer2.then();
+
+	defer2.resolve( 2 );
+
+	piped2.done(function( value ) {
+		strictEqual( this, piped2, "default context gets updated to latest promise in the chain (without passing function)" );
+		strictEqual( value, 2, "proper value received (without passing function)" );
+	});
 });
 
 test( "jQuery.when", function() {