774304 - java.lang.NullPointerException: at org.mozilla.gecko.MultiChoicePreference.onDialogClosed(MultiChoicePreference.java)

Status: VERIFIED FIXED

(Firefox for Android Graveyard :: General, defect)

Description

[Scoobidiver (away)]

There are two crashes in 15.0a2, including: bp-231d0ef1-0f4a-41c4-a2dc-e2efc2120716.

java.lang.NullPointerException
	at org.mozilla.gecko.MultiChoicePreference.onDialogClosed(MultiChoicePreference.java:165)
	at org.mozilla.gecko.PrivateDataPreference.onDialogClosed(PrivateDataPreference.java:34)
	at android.preference.DialogPreference.onDismiss(DialogPreference.java:381)
	at android.app.Dialog$ListenersHandler.handleMessage(Dialog.java:1259)
	at android.os.Handler.dispatchMessage(Handler.java:99)
	at android.os.Looper.loop(Looper.java:154)
	at android.app.ActivityThread.main(ActivityThread.java:4945)
	at java.lang.reflect.Method.invokeNative(Native Method)
	at java.lang.reflect.Method.invoke(Method.java:511)
	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
	at dalvik.system.NativeStart.main(Native Method)

More reports at:
https://crash-stats.mozilla.com/report/list?signature=java.lang.NullPointerException%3A+at+org.mozilla.gecko.MultiChoicePreference.onDialogClosed%28MultiChoicePreference.java%29

Comment 1

[:Margaret Leibovic]

Looks like mPrevValues is null here:
http://hg.mozilla.org/releases/mozilla-aurora/annotate/tip/mobile/android/base/MultiChoicePreference.java#l165

Comment 2

[Brian Nicholson (:bnicholson)]

Attachment: Make initialization of MultiChoicePreference synchronous

This is likely happening because onDialogClosed() is getting called before the Runnable in loadPersistedValues() is run - and that's where we do the initialization. I think I threw this part in a handler to avoid a StrictMode violation, but this is probably one of those cases where we can just ignore it. There's not much we can do on the UI thread anyway until we've loaded the persistent prefs.

Comment 3

[Mark Finkle (:mfinkle) (use needinfo?)]

(In reply to Brian Nicholson (:bnicholson) from comment #2)
> Created attachment 670642 [details] [diff] [review]
> Make initialization of MultiChoicePreference synchronous
> 
> This is likely happening because onDialogClosed() is getting called before
> the Runnable in loadPersistedValues() is run

So the dialog is being closed before the initialization is complete? I don't like using a sync pref load. We try to avoid that whenever possible. In this case, the sync load would affect all users.

Could we protect onDialogClosed with some null checks?

Comment 4

[Brian Nicholson (:bnicholson)]

Attachment: Check for null pref values when closing MultiChoicePreference

Comment 5

[Brian Nicholson (:bnicholson)]

http://hg.mozilla.org/integration/mozilla-inbound/rev/421315a62cb5

Comment 6

[Brian Nicholson (:bnicholson)]

Comment on attachment 672866 [details] [diff] [review]
Check for null pref values when closing MultiChoicePreference

[Approval Request Comment]
Bug caused by (feature/regressing bug #): 
User impact if declined: potential crashes
Testing completed (on m-c, etc.): just landed m-i
Risk to taking this patch (and alternatives if risky): very low risk (just null pointer check)
String or UUID changes made by this patch: none

Comment 7

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/421315a62cb5

Comment 8

[Brian Nicholson (:bnicholson)]

http://hg.mozilla.org/releases/mozilla-aurora/rev/10a89f81cae9

Comment 9

[Brian Nicholson (:bnicholson)]

http://hg.mozilla.org/releases/mozilla-beta/rev/c1c29d889d3e

Comment 10

[Kevin Brosnan [Ex-Mozilla]]

No 17 or 18 crashes marking as verified.