Support Log.wtf about timber

[AndrewReitz]

I was under the impression that wtf log level was a joke.

[JakeWharton]

Does anyone use this log level? The documentation says that your process could outright be killed if you do. I don't think there's a lot of utility in exposing it inside Timber.

[JakeWharton]

It crashes your app.

https://github.com/android/platform_frameworks_base/blob/master/services/java/com/android/server/am/ActivityManagerService.java#L9874

[donnfelker]

Updated link as above link is dead: https://github.com/android/platform_frameworks_base/blob/master/services/core/java/com/android/server/am/ActivityManagerService.java#L11853

[donnfelker]

I need WTF for our project. We forked android so we control the system global setting, WTF_IS_FATAL, and we've set it to false. If I implement WTF will you accept it as a PR?

[JakeWharton]

Yes.

Why do you explicitly choose to use it?

[donnfelker]

Personally I have never used it but was convinced for this special use case that we're in with our device. We hook into the system and grab the WTF's and send them up to our servers where we actively monitor them and react to them internally. We only log extreme, definite "this should never happen" type of scenarios so we know if they actually do happen in prod. One such example would be - A new device being ships and it is not configured as we expect from the factory/etc.

[donnfelker]

@JakeWharton Would like to see what you think about this ...

WTF has an interesting implementation as it depends on this non-public method: https://github.com/android/platform_frameworks_base/blob/master/core/java/android/util/Log.java#L289

All other log levels (v/d/i/w/e) log to println_native where wtf calls this the method linked above. In the Timber#logMessage call I can implement a couple of ifs so that it calls the actual WTF methods if the priority is ASSERT so the underlying wtf implementation is called. This would take two if statements -

1. If message is less than MAX_LOG_LENGTH
2. If over MAX_LOG_LENGTH (within while loop)

My gut says this feels a bit hacky because we're assuming that all ASSERT's are wtf's, but I'm not sure what might be best in this scenario. Whats your opinion on it? Thoughts?

[donnfelker]

See the code above for what I'm talking about. Looking forward to feedback.

[JakeWharton]

I think what you said is fine. It is only slightly hacky, but I'm pretty comfortable with it since the levels are fixed (knock on wood) and unlikely to ever change or be expanded further (and thus necessitate more hacks).

[donnfelker]

Do we want to merge this in for a new release? Yes/No?

[JakeWharton]

Merged to master. Need the weekend to bake the release to see if anything else needs to be included.

[donnfelker]

Awesome. Thanks!