alpha linear-gradient background-image produces dark line at edge

• Component: CSS
• Status: RESOLVED FIXED

[Chris Rebert]

Created attachment 243535 [details]
Screenshot of the bug; note dark vertical line on right side of slide

Safari Version 8.0.2 (10600.2.5)
OS X Yosemite 10.10.1 (14B25)

To reproduce:
0. Go to a Mac with a non-retina screen.
1. In Safari 8, open http://getbootstrap.com/javascript/#carousel
       or http://bootstrapdocs.com/v3.2.0/docs/javascript/#carousel
2. Resize the window horizontally while observing the right side of the carousel.
3. As you resize, you'll observe a dark vertical line flicker in and out of view (see screenshot).
4. While the line is visible, stop resizing. The line will remain visible.
You can refresh the page or open the same page in a new tab (while keeping the window the same size)
to confirm that the bug is not related to resizing. (It's just necessary to discover what are the
right "magic" window widths where the bug is visible.)

Expected results:
There should be no dark vertical line at the edge of the alpha-channel gradient.

Further info:
If you inspect the
    <a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">
in the carousel (i.e. the carousel's right arrow)
and disable its "background-image: linear-gradient" CSS styles,
you'll observe that the line disappears, which indicates that the line is due to the gradient.

Original Bootstrap issue: https://github.com/twbs/bootstrap/issues/15205

[Chris Rebert]

Have also filed this as <rdar://problem/19434933>

[Simon Fraser (smfr)]

I can't reproduce this in a recent WebKit nightly.

[Chris Rebert]

Confirmed fixed as of r186963.
I've removed the entry from Bootstrap's Wall of Browser Bugs:
https://github.com/twbs/bootstrap/pull/16841