922931 - Broken images should be discoverable if alt is unset (NOT empty string), even in standard-mode

Status: RESOLVED FIXED

(Core :: Layout: Images, Video, and HTML Frames, defect)

Description

[Masatoshi Kimura [:emk]]

The HTML spec recommends displaying something to indicate the user.[1] It does not depend on the rendering mode.
We don't have to care if the alt text is clipped because the alt text is not present :)

[1] http://www.whatwg.org/specs/web-apps/current-work/multipage/embedded-content-1.html#the-img-element

Comment 1

[Masatoshi Kimura [:emk]]

The current workaround:
img { -moz-force-broken-image-icon: 1 }
img[alt] { -moz-force-broken-image-icon: 0 }

Comment 2

[Masatoshi Kimura [:emk]]

Attachment: patch

Comment 3

[Masatoshi Kimura [:emk]]

Try runs:
https://tbpl.mozilla.org/?tree=Try&rev=65d7457c23d9
https://tbpl.mozilla.org/?tree=Try&rev=3e9d95f84214

Comment 4

[Boris Zbarsky [:bzbarsky]]

Hmm.  So the actual spec requirement for the layout here is at http://www.whatwg.org/specs/web-apps/current-work/multipage/rendering.html#rendering and says:

  When an img element might be a key part of the content, but neither the image nor any 
  kind of alternative text is available, and the user agent does not expect this to
  change, the element is expected to be treated as a non-replaced phrasing element whose
  content is an icon indicating that an image is missing.

That's not what this patch does, and might well not be web-compatible (e.g. in cases when the current sized box is smaller than the icon size).  Do we need to get the spec changed here?

Comment 5

[Masatoshi Kimura [:emk]]

(In reply to Boris Zbarsky [:bz] from comment #4)
> That's not what this patch does, and might well not be web-compatible (e.g.
> in cases when the current sized box is smaller than the icon size).  Do we
> need to get the spec changed here?

I'm for changing the spec.

Comment 6

[Boris Zbarsky [:bzbarsky]]

OK.  Do you want to file the spec issue, then?

Comment 7

[Masatoshi Kimura [:emk]]

Filed <https://www.w3.org/Bugs/Public/show_bug.cgi?id=23443>.

Comment 8

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 813846 [details] [diff] [review]
patch

>+++ b/dom/imptests/failures/editing/conformancetest/test_runtest.html.json

Hmm.  Why was the change to this file needed?

r=me for the rest.

Comment 9

[Masatoshi Kimura [:emk]]

(In reply to Boris Zbarsky [:bz] from comment #8)
> >+++ b/dom/imptests/failures/editing/conformancetest/test_runtest.html.json
> 
> Hmm.  Why was the change to this file needed?

Because otherwise the test "passed" unexpectedly.
Looks like our |document.execCommand("forwarddelete", ...);| ignores img elements which represent nothing. So it removed the character "b" instead of the broken img without this patch.

Comment 10

[Boris Zbarsky [:bzbarsky]]

Ah, I see.  Thanks!

Comment 11

[Masatoshi Kimura [:emk]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/8434bf06134c

Comment 12

[Ekanan Ketunuti]

https://hg.mozilla.org/mozilla-central/rev/8434bf06134c

Comment 13

[Jason Smith [:jsmith]]

Note - this suspected to be the root cause of bug 985173.