Update CopyGoogleServicesPlugin (#7454)

This change alters the plugin to include a default google-services.json
file that can be copied into the test app if the google-services.json is
not present for some reason.

This is highly conditional to maintain the existing workflow of using
the test apps to actually test the sdks

---------

Co-authored-by: David Motsonashvili <[email protected]>

Author: davidmotson

plugins/resources/dummy-google-services.json

@@ -0,0 +1,24 @@
+{
+  "project_info": {
+    "project_number": "000000000",
+    "firebase_url": "https://fakeProject.firebaseio.com",
+    "project_id": "fakeProject",
+    "storage_bucket": "fakeProject.firebasestorage.app"
+  },
+  "client": [
+    {
+      "client_info": {
+        "mobilesdk_app_id": "1:0000000:android:fakeProjectCopyGoogleServices",
+        "android_client_info": {
+          "package_name": "com.example.myapplication"
+        }
+      },
+      "api_key": [
+        {
+          "current_key": "aFakeKeyBecauseThisWholeJsonFileIsFake"
+        }
+      ]
+    }
+  ],
+  "configuration_version": "1"
+}

plugins/src/main/java/com/google/firebase/gradle/plugins/CopyGoogleServicesPlugin.kt

@@ -17,6 +17,7 @@
 package com.google.firebase.gradle.plugins
 
 import com.android.build.gradle.BaseExtension
+import com.android.build.gradle.internal.tasks.factory.dependsOn
 import java.io.File
 import org.gradle.api.Plugin
 import org.gradle.api.Project
@@ -25,7 +26,8 @@ import org.gradle.kotlin.dsl.getByType
 import org.gradle.kotlin.dsl.register
 
 /**
- * Copies the root google-services.json into the project directory during build time.
+ * Copies the root google-services.json into the project directory during build time. If the file
+ * doesn't exist, a dummy file is created and copied instead
  *
  * If a path is provided via `FIREBASE_GOOGLE_SERVICES_PATH`, that will be used instead. The file
  * will also be renamed to `google-services.json`, so provided files do *not* need to be properly
@@ -35,12 +37,20 @@ import org.gradle.kotlin.dsl.register
  */
 abstract class CopyGoogleServicesPlugin : Plugin<Project> {
   override fun apply(project: Project) {
-    val copyRootGoogleServices = registerCopyRootGoogleServicesTask(project)
+    if (File(project.projectDir, "google-services.json").exists()) {
+      project.logger.warn("Google Services file already present in project, skipping copy task")
+      return
+    }
+
+    val sourcePath = getSourcePath(project)
+    val copyRootGoogleServices = registerCopyRootGoogleServicesTask(project, sourcePath)
 
     project.allprojects {
       // fixes dependencies with gradle tasks that do not properly dependOn `preBuild`
       tasks.configureEach {
-        if (name !== "copyRootGoogleServices") dependsOn(copyRootGoogleServices)
+        if (name !== "copyRootGoogleServices") {
+          dependsOn(copyRootGoogleServices)
+        }
       }
     }
 
@@ -56,22 +66,19 @@ abstract class CopyGoogleServicesPlugin : Plugin<Project> {
     return gradle.startParameter.taskNames.any { testTasks.any(it::contains) }
   }
 
-  private fun registerCopyRootGoogleServicesTask(project: Project) =
+  private fun registerCopyRootGoogleServicesTask(project: Project, path: String) =
     project.tasks.register<Copy>("copyRootGoogleServices") {
-      val sourcePath =
-        System.getenv("FIREBASE_GOOGLE_SERVICES_PATH") ?: "${project.rootDir}/google-services.json"
-
       val library = project.extensions.getByType<BaseExtension>()
 
       val targetPackageLine = "\"package_name\": \"${library.namespace}\""
       val packageLineRegex = Regex("\"package_name\":\\s+\".*\"")
 
-      from(sourcePath)
+      from(path)
       into(project.projectDir)
 
       rename { "google-services.json" }
 
-      if (fileIsMissingPackageName(sourcePath, targetPackageLine)) {
+      if (fileIsMissingPackageName(path, targetPackageLine)) {
         /**
          * Modifies `google-services.json` such that all declared `package_name` entries are
          * replaced with the project's namespace. This tricks the google services plugin into
@@ -91,4 +98,14 @@ abstract class CopyGoogleServicesPlugin : Plugin<Project> {
 
     return !file.readText().contains(targetPackageLine)
   }
+
+  private fun getSourcePath(project: Project): String {
+    val path =
+      System.getenv("FIREBASE_GOOGLE_SERVICES_PATH") ?: "${project.rootDir}/google-services.json"
+    if (File(path).exists()) {
+      return path
+    }
+    project.logger.warn("Google services file not found, using fallback")
+    return "${project.rootDir}/plugins/resources/dummy-google-services.json"
+  }
 }