Bug 263712

Summary: Removing an item from rect (SVGTransformList) prevents attribute removal
Product: WebKit Reporter: Ahmad Saleem <ahmad.saleem792>
Component: SVGAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: ashvayka, cdumez, karlcow, sabouhallawa, webkit-bug-importer, zimmermann
Priority: P2 Keywords: BrowserCompat, InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=232128
Attachments:
Description Flags
steps in devtools of safari and firefox none

Description Ahmad Saleem 2023-10-26 01:55:47 PDT 
Hi Team,

While going through Blink's bug, I came across another where we differ:

Test Case: https://jsfiddle.net/b56f2v8e/

^ Console logs 'true' for STP181 while 'false' for Chrome Canary 120 and Firefox Nightly 121.

Chrome Bug: crbug.com/843901

Just wanted to raise so we can track and fix it.

Thanks!
Comment 1 Radar WebKit Bug Importer 2023-11-02 01:56:12 PDT 
<rdar://problem/117840533>
Comment 2 Karl Dubost 2023-11-19 23:31:08 PST 
Created attachment 468670 [details]
steps in devtools of safari and firefox

These are the steps in both browsers for the script. 

var elem = document.createElementNS('http://www.w3.org/2000/svg', 'rect');
elem.setAttribute('transform', 'matrix(1,0,0,1,0,0)');
elem.transform.baseVal.removeItem(0);
elem.removeAttribute('transform');
console.log(elem.hasAttribute('transform'));


The interesting differences are starting once the following has been applied. 
"elem.transform.baseVal.removeItem(0)"

Firefox: <rect transform=""></rect>
Safari:  <rect transform="matrix(1,0,0,1,0,0)"></rect>

then applying "elem.removeAttribute('transform')"
gives the same result

Firefox: <rect></rect>
Safari:  <rect></rect>

BUT doing "elem.hasAttribute('transform')"

Firefox: false
Safari:  true

which is not logical with the previous result.
Comment 3 Karl Dubost 2023-11-19 23:41:12 PST 
it seems like there is not a complete synchronization of the element state.
Comment 4 Nikolas Zimmermann 2023-11-20 00:29:49 PST 
Good catch Karl. Indeed this is the „lazy SVG attribute synchronization“ that apparently exposes this bug. We probably fail to unmap properly..