Draggable: Recalculate hash offset on start after plugins run

 Fixes #6884

tests/unit/draggable/draggable_events.js

@@ -118,8 +118,47 @@ test( "stopping the stop callback", function() {
	});

	ok( element.draggable( "instance" ).helper, "the clone should not be deleted if the stop callback is stopped" );
});

// http://bugs.jqueryui.com/ticket/6884
// Draggable: ui.offset.left differs between the "start" and "drag" hooks
test( "position and offset in hash is consistent between start, drag, and stop", function() {
	expect( 4 );

	var startPos, startOffset, dragPos, dragOffset, stopPos, stopOffset;

	element = $( "<div style='margin: 2px;'></div>" ).appendTo( "#qunit-fixture" );

	element.draggable({
		start: function( event, ui ) {
			startPos = ui.position;
			startOffset = ui.offset;
		},
		drag: function( event, ui ) {
			dragPos = ui.position;
			dragOffset = ui.offset;
		},
		stop: function( event, ui ) {
			stopPos = ui.position;
			stopOffset = ui.offset;
		}
	});

	element.simulate( "drag", {
		dx: 10,
		dy: 10,
		moves: 1
	});

	startPos.left += 10;
	startPos.top += 10;
	startOffset.left += 10;
	startOffset.top += 10;

	deepEqual( startPos, dragPos, "start position equals drag position plus distance" );
	deepEqual( dragPos, stopPos, "drag position equals stop position" );
	deepEqual( startOffset, dragOffset, "start offset equals drag offset plus distance" );
	deepEqual( dragOffset, stopOffset, "drag offset equals stop offset" );
});

})( jQuery );

ui/draggable.js

@@ -614,9 +614,10 @@ $.widget("ui.draggable", $.ui.mouse, {
		ui = ui || this._uiHash();
		$.ui.plugin.call( this, type, [ event, ui, this ], true );

		// The absolute position has to be recalculated after plugins
		if ( type === "drag" ) {
		// Absolute position and offset (see #6884 ) have to be recalculated after plugins
		if ( /^(drag|start|stop)/.test( type ) ) {
			this.positionAbs = this._convertPositionTo( "absolute" );
			ui.offset = this.positionAbs;
		}
		return $.Widget.prototype._trigger.call( this, type, event, ui );
	},