push_apk.py: Verify files in APKs are not all compressed

[JohanLorenzo]

See https://bugzilla.mozilla.org/show_bug.cgi?id=1513870 and https://bugzilla.mozilla.org/show_bug.cgi?id=1506598 for context.

There are some (TBD[1]) files that must remain deflated. Due to a misconfiguration of autograph, we may end up with an APK that crashes. This check doesn't exist on Google Play.

For reference, even though Fennec 65.0b4 (bug 1513870) was uploaded manually, I did use mozapkpublisher. This means if this check was implemented, we would have caught the malformation of the APKs.

[1] We know at least these https://searchfox.org/mozilla-central/rev/232ced2697b8938073fa79b8e6aa3718876c0b69/python/mozbuild/mozbuild/action/package_fennec_apk.py#97-98. I remember seeing some others. Let's deep dive into some published APKs.

[lundjordan]

@JohanLorenzo - is this something we should prioritize? Does it still apply in today's world?

[JohanLorenzo]

This bug hasn't bitten us since December. That said, it's easy to forget about it and make the same mistake once again. The impact of this mistake is quite high:

1. we ship a crashing APK
2. users notice it and file a
3. this report goes through the regular crash workflow, until someone notice the APK doesn't look right
4. a new release is made to avoid that top crasher.

I would love to have this check baked in, for sake of other teams.