Android库中的Firebase依赖关系：无法在null对象上调用方法get（）

Question

在向android库添加firebase依赖项时，我遇到了构建问题。

我的设置如下

/settings.gradle

include ':module-lib'
include ':module-app'

/build.gradle

buildscript {
  dependencies {
    classpath 'com.android.tools.build:gradle:3.1.2'
    classpath 'com.google.gms:google-services:4.0.0'
  } 
}

/module-lib/build.gradle

apply plugin: 'com.android.library'
android {
   ...
}
dependencies{
  api "com.google.firebase:firebase-config:16.0.0"  
}

/module-app/build.gradle

apply plugin: 'com.android.application'
android {
   ...
}
dependencies {
  implementation project(':module-lib') 
}
apply plugin: 'com.google.gms.google-services'

短日志：

$ ./gradlew clean build

Starting a Gradle Daemon, 1 busy and 2 stopped Daemons could not be reused, use --status for details

Parallel execution is an incubating feature.

> Configure project :module-app
Detected alwaysUpdateBuildId set to false while obfuscation is enabled. This may result in obfuscated stack traces in Crashlytics.
registerResGeneratingTask is deprecated, use registerGeneratedResFolders(FileCollection)
registerResGeneratingTask is deprecated, use registerGeneratedResFolders(FileCollection)
registerResGeneratingTask is deprecated, use registerGeneratedResFolders(FileCollection)
registerResGeneratingTask is deprecated, use registerGeneratedResFolders(FileCollection)

> Task :module-lib:compileDebugAidl FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Failed to notify dependency resolution listener.
> Cannot invoke method get() on null object
> Cannot invoke method get() on null object

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 18s
13 actionable tasks: 8 executed, 5 from cache

您可以在this pastebin

中找到原始错误的完整堆栈跟踪

有趣的事情是module-lib只包含占位符，空和无用的类。如果我从module-lib中删除了firebase依赖项并将其移至module-app，那么构建工作正常。

我没有使用Android Studio，因此这是纯粹的Gradle和/或插件  和/或依赖性问题。

另请注意

./gradlew clean       // Always succeds 
./gradlew build       // Sometimes works with above error 
./gradlew clean build // Always fails with above error

在应用库插件firebase-*的模块中包含的任何com.android.library依赖项也会发生这种情况。

更多环境信息

$ ./gradlew -version

------------------------------------------------------------
Gradle 4.7
------------------------------------------------------------

Build time:   2018-04-18 09:09:12 UTC
Revision:     b9a962bf70638332300e7f810689cb2febbd4a6c

Groovy:       2.4.12
Ant:          Apache Ant(TM) version 1.9.9 compiled on February 2 2017
JVM:          1.8.0_162 (Oracle Corporation 25.162-b12)
OS:           Mac OS X 10.13.4 x86_64

任何线索或提示都非常受欢迎:)

谢谢！

Answer 1

将google-services插件升级到版本4.0.1可以解决此问题。

从Firebase sdk更改日志页面：https://firebase.google.com/support/release-notes/android

换句话说，更改此内容：

classpath 'com.google.gms:google-services:4.0.0'

对此：

classpath 'com.google.gms:google-services:4.0.1'