feat(api): provide task guards for lazy register

This update provides a way to use the basic AffectedModuleDetector task
guard when leveraging the `register` api to create tasks, without
needing to explicitly get the task immediately. This allows for the AMD
calculation to be evaluated lazily, and avoids performing work on tasks
that will not be executed.

Author: ffluk3

affectedmoduledetector/src/main/kotlin/com/dropbox/affectedmoduledetector/AffectedModuleDetector.kt

@@ -32,6 +32,7 @@ import org.gradle.api.Project
 import org.gradle.api.Task
 import org.gradle.api.UnknownDomainObjectException
 import org.gradle.api.logging.Logger
+import org.gradle.api.tasks.TaskProvider
 import java.io.File
 
 /**
@@ -140,9 +141,11 @@ abstract class AffectedModuleDetector {
                 rootProject.hasProperty(DEPENDENT_PROJECTS_ARG) -> {
                     ProjectSubset.DEPENDENT_PROJECTS
                 }
+
                 rootProject.hasProperty(CHANGED_PROJECTS_ARG) -> {
                     ProjectSubset.CHANGED_PROJECTS
                 }
+
                 else -> {
                     ProjectSubset.ALL_AFFECTED_PROJECTS
                 }
@@ -153,7 +156,7 @@ abstract class AffectedModuleDetector {
                     rootProject.extensions.findByType(AffectedModuleConfiguration::class.java)
                 ) {
                     "Root project ${rootProject.path} must have the AffectedModuleConfiguration " +
-                        "extension added."
+                            "extension added."
                 }
 
             val logger =
@@ -232,7 +235,7 @@ abstract class AffectedModuleDetector {
         }
 
         /**
-         * Call this method to configure the given task to execute only if the owner project
+         * Call this method to configure the given provided task to execute only if the owner project
          * is affected by current changes
          *
          * Can be called during the configuration or execution phase
@@ -247,6 +250,24 @@ abstract class AffectedModuleDetector {
             }
         }
 
+        /**
+         * Call this method to configure the given task to execute only if the owner project
+         * is affected by current changes
+         *
+         * Can be called during the configuration or execution phase
+         */
+        @Throws(GradleException::class)
+        @JvmStatic
+        fun configureTaskGuard(taskProvider: TaskProvider<out Task>) {
+            taskProvider.configure { task ->
+                task.onlyIf {
+                    getOrThrow(
+                        task.project
+                    ).shouldInclude(task.project)
+                }
+            }
+        }
+
         /**
          * Call this method to determine if the project was affected in this change
          *
@@ -340,7 +361,11 @@ class AffectedModuleDetectorImpl constructor(
         injectedGitClient ?: GitClientImpl(
             rootProject.projectDir,
             logger,
-            commitShaProvider = CommitShaProvider.fromString(config.compareFrom, config.specifiedBranch, config.specifiedRawCommitSha),
+            commitShaProvider = CommitShaProvider.fromString(
+                config.compareFrom,
+                config.specifiedBranch,
+                config.specifiedRawCommitSha
+            ),
             ignoredFiles = config.ignoredFiles
         )
     }
@@ -399,9 +424,11 @@ class AffectedModuleDetectorImpl constructor(
             changedProjects.contains(project.projectPath) -> {
                 ProjectSubset.CHANGED_PROJECTS
             }
+
             dependentProjects.contains(project.projectPath) -> {
                 ProjectSubset.DEPENDENT_PROJECTS
             }
+
             else -> {
                 ProjectSubset.NONE
             }
@@ -435,13 +462,13 @@ class AffectedModuleDetectorImpl constructor(
                 unknownFiles.add(filePath)
                 logger?.info(
                     "Couldn't find containing project for file$filePath. " +
-                        "Adding to unknownFiles."
+                            "Adding to unknownFiles."
                 )
             } else {
                 changedProjects[containingProject.projectPath] = containingProject
                 logger?.info(
                     "For file $filePath containing project is $containingProject. " +
-                        "Adding to changedProjects."
+                            "Adding to changedProjects."
                 )
             }
         }
@@ -487,7 +514,7 @@ class AffectedModuleDetectorImpl constructor(
         }
         logger?.info(
             "unknownFiles: $unknownFiles, changedProjects: $changedProjects, buildAll: " +
-                "$buildAll"
+                    "$buildAll"
         )
 
         // If we're in a buildAll state, we return allProjects unless it's the changed target,