1315938 - Crash in java.lang.NullPointerException: Attempt to invoke virtual method ''boolean org.mozilla.gecko.Tab.isPrivate()'' on a null object reference at org.mozilla.gecko.home.TwoLinePageRow.updateDisplayedUrl(TwoLinePageRow.java)

Status: RESOLVED FIXED

(Firefox for Android Graveyard :: Awesomescreen, defect, P1)

Description

[Andrzej Hunt :ahunt]

This bug was filed from the Socorro interface and is 
report bp-ce33a3a6-c248-4e4a-8f5c-3be1e2161107.
=============================================================

This is number 10 on Aurora, and is likely to be a simple fix.

Comment 1

[Andrzej Hunt :ahunt]

I've fiddled with TopSites a lot in the past, so I am probably a good candidate for looking into this.

Comment 2

[Andrzej Hunt :ahunt]

Attachment: Bug 1315938 - Don't crash if tabs aren't initialised yet

getSelectedTab() specifies that it can return null "if we're doing a
session restore after a crash and Gecko isn't ready yet". This seems
to occasionally be happening, resulting in crashes.

(What isn't clear is why this would be happening more regularly in 51,
 it's possible some completely unrelated changes are either making
 the rendering of TopSites faster, causing this call to be made earlier,
 or session restore has simply gotten slower. We have also had a
 crash spike recently due to library loading issues, which would
 likely further exacerbate the whole issue.)

Review commit: https://reviewboard.mozilla.org/r/91396/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/91396/

Comment 3

[Sebastian Kaspari (:sebastian; :pocmo)]

Comment on attachment 8808590 [details]
Bug 1315938 - Don't crash if tabs aren't initialised yet

https://reviewboard.mozilla.org/r/91396/#review91636

Comment 4

[Sebastian Kaspari (:sebastian; :pocmo)]

Let's uplift this to 51.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/bc22ca7ff05b
Don't crash if tabs aren't initialised yet r=sebastian

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/bc22ca7ff05b

Comment 7

[Andrzej Hunt :ahunt]

Comment on attachment 8808590 [details]
Bug 1315938 - Don't crash if tabs aren't initialised yet

Approval Request Comment
[Feature/regressing bug #]: Unknown - this bug seems to have always been present, but is only triggered in certain scenarios.
[User impact if declined]: Startup crash if gecko is slow to load, or doesn't load.
[Describe test coverage new/current, TreeHerder]: none (patch has been stabilised on nightly, no obvious issues visible).
[Risks and why]: low risk - add null-check for a call that is specified to return null in certain scenarios.
[String/UUID change made/needed]: none.

This crash is currently 20th on Nightly, 15th on Aurora. It seemed to spike with the recent library loading issues (which would prevent gecko from being started before topsites is shown), however this is a beneficial fix in general. Without this patch we have a race condition between topsites being shown, and gecko loading, with a crash when topsites are shown first.

Comment 8

[Gerry Chang [:gchang]]

Comment on attachment 8808590 [details]
Bug 1315938 - Don't crash if tabs aren't initialised yet

Fix a crash. Aurora51+.

Comment 9

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/releases/mozilla-aurora/rev/36f945043957