757657 - Sometimes get "GeckoActivity.java:24: warning: [cast] redundant cast..." when building

Status: RESOLVED INCOMPLETE

(Firefox for Android Graveyard :: General, defect)

Description

[Doug Sherk (:drs) (inactive)]

I using OpenJDK 7, I sometimes get the following error when building:

GeckoActivity.java:24: warning: [cast] redundant cast to org.mozilla.gecko.GeckoApplication
            ((GeckoApplication) getApplication()).onActivityPause(this);
             ^
GeckoActivity.java:33: warning: [cast] redundant cast to org.mozilla.gecko.GeckoApplication
            ((GeckoApplication) getApplication()).onActivityResume(this);
             ^
GeckoActivity.java:70: warning: [cast] redundant cast to org.mozilla.gecko.GeckoApplication
        return ((GeckoApplication) getApplication()).isApplicationInBackground();
                ^
error: warnings found and -Werror specified
1 error
3 warnings
make[6]: *** [classes.dex] Error 1
make[6]: Leaving directory `/home/dsherk/mozilla-central/objdir-droid/mobile/android/base'
make[5]: *** [libs] Error 2
make[5]: Leaving directory `/home/dsherk/mozilla-central/objdir-droid/mobile/android'
make[4]: *** [libs_tier_app] Error 2
make[4]: Leaving directory `/home/dsherk/mozilla-central/objdir-droid'
make[3]: *** [tier_app] Error 2
make[3]: Leaving directory `/home/dsherk/mozilla-central/objdir-droid'
make[2]: *** [default] Error 2
make[2]: Leaving directory `/home/dsherk/mozilla-central/objdir-droid'
make[1]: *** [realbuild] Error 2
make[1]: Leaving directory `/home/dsherk/mozilla-central'
make: *** [build] Error 2

This never happens on a fresh checkout. Clobbering fixes it. kats suspects that it is caused by the instanceof check directly above the cast, which causes there to be two instanceof calls in the bytecode.

Comment 1

[Kartikaya Gupta (email:[e-mail])]

I'm unable to reproduce this locally building with OpenJDK 7 on Linux. I'm also confused as to why it would never happen on a clobber build or fresh checkout; that implies it's not what I thought but that something is being cached somewhere. Does your compiler have any modifications or extensions or anything of that sort?

Comment 2

[Kartikaya Gupta (email:[e-mail])]

Unassigning to myself since I can't repro it and therefore can't debug it.

Comment 3

[Doug Sherk (:drs) (inactive)]

Can you provide a suggested fix so I can try it next time I get it?

Comment 4

[Kartikaya Gupta (email:[e-mail])]

My best guess involves removing the two "instanceof GeckoApplication" checks entirely. The isApplicationInBackground function doesn't do the instanceof check, which the compiler might mistake as a hint that getApplication() always returns a GeckoApplication, making the casts redundant.

Comment 5

[Doug Sherk (:drs) (inactive)]

I haven't had this in several days, in contrast to before where it was several times a day. I haven't applied any fix so I'm not sure whether it has just gone away or I was unlucky before. I'm closing this for now and I'll re-open it if it comes up again.

Comment 6

[Nick Alexander :nalexander [he/him]]

This is happening for me, 3 times today.

Comment 7

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

It's a javac bug; doing a clean in mobile/android/base resolves it.

Comment 8

[BMO Automation]

We have completed our launch of our new Firefox on Android. The development of the new versions use GitHub for issue tracking. If the bug report still reproduces in a current version of [Firefox on Android nightly](https://play.google.com/store/apps/details?id=org.mozilla.fenix) an issue can be reported at the [Fenix GitHub project](https://github.com/mozilla-mobile/fenix/). If you want to discuss your report please use [Mozilla's chat](https://wiki.mozilla.org/Matrix#Connect_to_Matrix) server https://chat.mozilla.org and join the [#fenix](https://chat.mozilla.org/#/room/#fenix:mozilla.org) channel.