1065119 - Setting img src when <picture> source is in use incorrectly adds fallback source

Status: RESOLVED WORKSFORME

(Core :: DOM: Core & HTML, defect)

Description

[John Schoenick [:johns]]

HTMLImageElement::AfterSetAttr doesn't check that the responsive source == self before updating the default source, so in the situation where you have a <picture> using a <source> that only provides > 1x density, we incorrectly pick up the img.src as a 1x density fallback if it is set afterwards.

This is caught by the tests for bug 1023519 but is also unfortunately being hit by this blog post about <picture>: https://longhandpixels.net/blog/2014/02/complete-guide-picture-element

Comment 1

[Edgar Chen [:edgar]]

HTMLImageElement already checks |responsive source == self| before updating the default source,
- https://dxr.mozilla.org/mozilla-central/source/dom/html/HTMLImageElement.cpp#429-432
- https://dxr.mozilla.org/mozilla-central/source/dom/html/HTMLImageElement.cpp#539-542

I also write a simple test to verify it, http://codepen.io/edgarchen/pen/ZWKMmm.
And current code seems work good.

Hi Josh, does this bug still exist? Or I'm missing something? Thank you.

Comment 2

[Josh Matthews [:jdm]]

You're right. Thank you for verifying it!