1161940 - [Stingray] Lost focus after pinning TV channel occasionally

Status: RESOLVED FIXED

(Firefox OS Graveyard :: Gaia::TV, defect)

Description

[Tzu-Lin Huang [:dwi2][:tzhuang]]

STR:
1. After boot-up, enter TV app
2. pin channel with lower-left pin button

Expected result:
Back to smart-home app and the focus is on the latest pinned TV channel

Actual result:
There are around 1/3 chances that the focus is still on TV app.

Comment 1

[John Hu [:johnhu][:johu][:醬糊小弟]]

I found a STR which almost gives us 100% reproduce ratio:

1. open tv deck
2. pin
3. press up/down while animation running

Comment 2

[John Hu [:johnhu][:johu][:醬糊小弟]]

I had put log at browser_mixin.js before blur and focus. The log shows it focuses to smart-home correct and no following logs. This means gaia doesn't call tv deck's focus(). But document.activeElement gives us tv deck at this time.

Comment 3

[John Hu [:johnhu][:johu][:醬糊小弟]]

I had tried another test case. I set an interval with 100ms. It showed that the focus had set to smart-home and after few ms, it goes back to tv deck.

Comment 4

[John Hu [:johnhu][:johu][:醬糊小弟]]

Sean,

This is the one I told you. Please help us to check it from gecko's point of view.

Comment 5

[John Hu [:johnhu][:johu][:醬糊小弟]]

Attachment: remove-focus.patch

It's so strange. If I remove the focus function call in TV deck, this issue is disappeared.

It seems the local focus in TV deck may affect the local focus in system app.

Comment 6

[John Hu [:johnhu][:johu][:醬糊小弟]]

Attachment: more specific test patch

We only need to remove this line to workaround it.

Comment 7

[John Hu [:johnhu][:johu][:醬糊小弟]]

Comment on attachment 8602015 [details] [diff] [review]
more specific test patch

False alarm.

This issue is so hard to reproduce. Once I applied this patch, the issue is still there.

Another STR to reproduce it is:
1. open TV deck
2. press enter continuously.

Comment 8

[John Hu [:johnhu][:johu][:醬糊小弟]]

Attachment: app-deck-test-patch.patch

We could reproduce the same issue with this patch. This is confirmed with Sung.

Comment 9

[John Hu [:johnhu][:johu][:醬糊小弟]]

STR of comment 8:

1. open app deck
2. press enter continuously

Once affected, you may find the focus moved to left top corner of app deck.

Comment 10

[John Hu [:johnhu][:johu][:醬糊小弟]]

Deassign myself until Sean Lin gives us more information.

Comment 11

[John Hu [:johnhu][:johu][:醬糊小弟]]

Take this back since we had offline discussion about this.

Comment 12

[GitHub Autolander Bot]

Attachment: [gaia] huchengtw-moz:bug-1161940-move-focus-to-known-element-while-animating > mozilla-b2g:master

Comment 13

[John Hu [:johnhu][:johu][:醬糊小弟]]

Comment on attachment 8602496 [details] [review]
[gaia] huchengtw-moz:bug-1161940-move-focus-to-known-element-while-animating > mozilla-b2g:master

Rex,

I had changed the code to move focus to an element instead of body to prevent other apps request focus from smart-home app. Please review this patch. Thanks.

Comment 14

[Sean Lin [:seanlin] (inactive from Mar 2016)]

The root cause is as follows (based on the STR in comment 9):

1. When the focus is set to smart-home, it only focuses the frame without explicitly setting focus to any element inside it. (The focused window is smart-home but focused content is null in this case.) 

2. So a follow-up attempt to set focus to a smart button in app-deck could "steal" the focus. (The focused window becomes app-deck and the focused content becomes the smart button.)

On the other hand, John's patch forces the focus on an element inside smart-home in step 1. Since the current focused content is non-null, the attempt in step 2 would trigger the security constraint [1] to prevent the focus move, since smart-home and app-deck cannot access each other's content due to same-origin policy.

[1] https://dxr.mozilla.org/mozilla-central/source/dom/base/nsFocusManager.cpp#1280-1298

Comment 15

[KM Lee [:rexboy] (inactivate after Sep. 22)]

Comment on attachment 8602496 [details] [review]
[gaia] huchengtw-moz:bug-1161940-move-focus-to-known-element-while-animating > mozilla-b2g:master

Basically it's OK but I'm not sure if it's the case on opening delete dialog. See my comments. Please discuss with me before landing.

Comment 16

[KM Lee [:rexboy] (inactivate after Sep. 22)]

Comment on attachment 8602496 [details] [review]
[gaia] huchengtw-moz:bug-1161940-move-focus-to-known-element-while-animating > mozilla-b2g:master

r=me but please move the function to a new util.js.
Thank you!

Comment 17

[GitHub Autolander Bot]

Pull request has landed in master: https://github.com/mozilla-b2g/gaia/commit/a1813c4535ad7177a797e29bf73bf6d0b9d97267