This upgrade of dependencies when used in conjunction with the other new firebase plugin versions causes problems due to the transitive android.arch.core version 1.1.0 dependencies from play-services-auth:16.0.1.

When mixing the 1.1.0 and 1.1.1 versions the dex fails as follows:

Gradle build fails while trying to dex with "Program type already present: android.arch.core.util.Function"

see: https://stackoverflow.com/questions/50524672/build-fails-with-program-type-already-present-android-arch-core-util-function

As a workaround until 'play-services-auth' bumps it's dependency I recommend either explicitly specifying version 1.1.1 of these libraries as a dependency or adding a note in the README documentation.

implementation "android.arch.core:runtime:1.1.1"
implementation "android.arch.core:common:1.1.1"

@JamesMcIntosh Would adding:

implementation "android.arch.core:runtime:1.1.1"
implementation "android.arch.core:common:1.1.1"

To this components build.gradle help? If so I will update the PR.

I tested and adding them as api dependencies fixes the issue.

api "android.arch.core:runtime:1.1.1"
api "android.arch.core:common:1.1.1"

I'm feel more like this should be added to the README as a known issue for this release / suggested workaround as this is a problem of interop between libraries since they are both libraries in the same project maybe one of the Google crew would like to throw in their thoughts. @bparrishMines ?

I dug a little bit further to see where the dependency incompatibility came from:

1. cloud_firestore bumps the version of firebase
2. This in turn bumps the version of android.arch.lifecycle to 1.1.1
3. This bumps the transitive dependency of android.arch.lifecycle in google_sign_in
4. It falls apart because android.arch.core:runtime is not a dependency of android.arch.lifecycle so remains at 1.1.0.

+--- project :google_sign_in
|    \--- com.google.android.gms:play-services-auth:16.0.1
|         +--- com.google.android.gms:play-services-auth-api-phone:16.0.0
|         |    +--- com.google.android.gms:play-services-base:16.0.1
|         |    |    +--- com.google.android.gms:play-services-basement:16.0.1
|         |    |    |    \--- com.android.support:support-v4:26.1.0 -> 27.1.1
|         |    |    |         +--- com.android.support:support-compat:27.1.1
|         |    |    |         |    +--- com.android.support:support-annotations:27.1.1
|         |    |    |         |    \--- android.arch.lifecycle:runtime:1.1.0 -> 1.1.1
|         |    |    |         |         +--- android.arch.lifecycle:common:1.1.1
...
+--- project :cloud_firestore
|    \--- com.google.firebase:firebase-firestore:17.1.1
|         +--- android.arch.lifecycle:common:1.1.1 (*)
|         +--- android.arch.lifecycle:runtime:1.1.1 (*)

@JamesMcIntosh updated the PR to match latest status on master. This would be good for a review now as it's a lot simpler.

Looks good to me but one of the Google crew will need to accept it.

@ened It seems like the CI is not happy about the formatting, I think I can merge this after you fix the CI errors.

@cyanglaz The CI is not happy about other things, too - but I don't think it's related to my PR. Please take a look.

@cyanglaz it’s green