1.10.0 breaks relative animation

[[email protected]…]

Relative animation (using += or -=) is broken in 1.10.0.

For example, $('h1').animate({marginLeft: '+=100px'}); does not work.

Minimal repro: ​http://jsfiddle.net/Me7QK/ (The example is broken on 1.10.0 but tested to work on 1.9.1, 1.8.3, 1.7.2, 1.6.4.)

This seems to be a bug in the default "*" tweener, where start is getting left as 'false' instead of actually being set to the actual start value in the normal case of a pixel-unit property. The following addition of an else for the if on line 19-41 of effects.js is one possible fix.

if ( start && start[ 3 ] !== unit ) {
  ...
} else {
  start = +target || 0;
}

[gibson042]

Confirmed. We have no unit tests covering relative animations. :O

[Richard Gibson]

Fix #13939: Same-unit relative animations (cherry picked from commit 00231d5d94d3374d53bfe79e04ba253250c73087)

Changeset: 26980c6ec96369bbaf87be1e405594df8ec3f0dc

[ajpiano]

If relative animations are completely broken in 1.10.1 but fixed now, I feel like this might necessitate an immediate 1.10.2, otherwise we're sure to get a fair number of dupe reports.

[scottgonzalez]

#13952 is a duplicate of this ticket.

[scottgonzalez]

#13940 is a duplicate of this ticket.

[[email protected]…]

But I thought ticket #13952 (closed bug) is not the same bug.

#13952 the point is the 'arguments.callee', not the 'px'; when the animate done, the (function(){})() just run once. ​http://jsfiddle.net/reyhappen/wF7VK/1/

<div id="book" style="position:relative;width:200px;height:200px;background:green;"></div>
<script src="http://code.jquery.com/jquery-1.10.0.min.js"></script>
<script>
$(function(){
    (function () {
        $("#book").animate({left: "+=10px"}, 1000, arguments.callee);
    })();
})
</script>

[scottgonzalez]

If it's a separate bug, please create a reduced test case that doesn't use relative animations and shows the problem. Add a link to that test case on the other ticket and we'll re-open.

[anonymous]

I think this is a very serious bug. Must be released hotfix.

[scottgonzalez]

#13960 is a duplicate of this ticket.

[[email protected]…]

The issue seems to when calculating tween.end. Changing

// If a +=/-= token was provided, we're doing a relative animation
tween.end = parts[ 1 ] ?
    //v--- bug
    start + ( parts[ 1 ] + 1 ) * parts[ 2 ] :  
   +parts[ 2 ];

to

// If a +=/-= token was provided, we're doing a relative animation
tween.end = parts[ 1 ] ?
    //v-- changed to tween.start
    tween.start + ( parts[ 1 ] + 1 ) * parts[ 2 ] :  
   +parts[ 2 ];

fixed the issue.

Fix tested with fiddle: ​http://jsfiddle.net/xEhuR/ [check line 8878 in script window]

[gibson042]

Yes meetselva, this was fixed 3 days ago by ​https://github.com/jquery/jquery/commit/00231d5d94d3374d53bfe79e04ba253250c73087 and will be in the next release.

[scottgonzalez]

#13963 is a duplicate of this ticket.