Fix plugin not working if module has a lot of dependencies

focus-gradle-plugin/src/main/kotlin/com/dropbox/focus/CreateFocusSettingsTask.kt

@@ -1,59 +1,89 @@
 package com.dropbox.focus
 
+import java.io.Serializable
 import org.gradle.api.DefaultTask
 import org.gradle.api.Project
 import org.gradle.api.artifacts.ProjectDependency
-import org.gradle.api.artifacts.SelfResolvingDependency
 import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.provider.Property
+import org.gradle.api.provider.SetProperty
+import org.gradle.api.tasks.Input
 import org.gradle.api.tasks.OutputFile
 import org.gradle.api.tasks.TaskAction
 import org.gradle.work.DisableCachingByDefault
 
 @DisableCachingByDefault(because = "Not worth caching")
 public abstract class CreateFocusSettingsTask : DefaultTask() {
 
+  @get:Input
+  protected abstract val projectDeps: SetProperty<DependentProjectInfo>
+
+  @get:Input
+  protected abstract val projectPath: Property<String>
+
   @get:OutputFile
   public abstract val settingsFile: RegularFileProperty
 
+  @get:OutputFile
+  public abstract val modulesToDirMapFile: RegularFileProperty
+
+  /**
+   * Project info required for focus.settings.gradle generation.
+   */
+  protected data class DependentProjectInfo(
+    public val path: String,
+    public val projectDir: String,
+  ): Serializable
+
   init {
     outputs.upToDateWhen { false }
   }
 
   @TaskAction
   public fun createFocusSettings() {
-    val dependencies = project.collectDependencies().sortedBy { it.path }
+    val dependencies = projectDeps.get().sortedBy { it.path }
+
+    // generate CSV mapping from module name to its absolute path
+    modulesToDirMapFile.get().asFile.writer().use { writer ->
+
+      dependencies
+        .forEach { dep ->
+          val projectPath = dep.path
+          val projectDir = dep.projectDir
+          writer.appendLine("$projectPath,$projectDir")
+        }
+    }
 
     settingsFile.get().asFile.writer().use { writer ->
-      writer.write("// ${project.path} specific settings\n")
+      writer.write("// ${projectPath.get()} specific settings\n")
       writer.appendLine("//")
       writer.appendLine("// This file is autogenerated by the focus task. Changes will be overwritten.")
       writer.appendLine()
 
-      // Add the includes statements
-      dependencies.forEach { dep ->
-        writer.appendLine("include(\"${dep.path}\")")
-      }
-
-      writer.appendLine()
-
-      // Add overrides for projects with a root that's different from the gradle path
-      dependencies
-        .forEach { dep ->
-          val gradleProjectPath = dep.path.substring(1).replace(":", "/")
-          if (project.rootDir.resolve(gradleProjectPath) != dep.projectDir) {
-            val gradleProjectDir = dep.projectDir.path.replace("\\", "\\\\")
-            // language=groovy
-            writer.appendLine("""project("${dep.path}").projectDir = new File('$gradleProjectDir')""")
+      // language=groovy
+      writer.append(
+        """
+        File f = new File("${modulesToDirMapFile.get().asFile.absolutePath}")
+        if (f.exists()) {
+          f.eachLine { line ->
+            var values = line.split(",")
+            var module = values[0]
+            var path = values[1]
+            include(module)
+            project(module).projectDir = new File(path)
           }
         }
+        """.trimIndent()
+      )
     }
   }
 
-  private fun Project.collectDependencies(): Set<Project> {
-    val result = mutableSetOf<Project>()
+  private fun Project.collectDependencies(): Set<DependentProjectInfo> {
+    val result = mutableSetOf<DependentProjectInfo>()
     fun addDependent(project: Project) {
       val configuredProject = this.evaluationDependsOn(project.path)
-      if (result.add(configuredProject)) {
+      val dep = DependentProjectInfo(project.path, project.projectDir.absolutePath)
+      if (result.add(dep)) {
         configuredProject.configurations.forEach { config ->
           config.dependencies
             .filterIsInstance<ProjectDependency>()
@@ -71,7 +101,11 @@ public abstract class CreateFocusSettingsTask : DefaultTask() {
     public operator fun invoke(subExtension: FocusSubExtension): CreateFocusSettingsTask.() -> Unit = {
       group = FOCUS_TASK_GROUP
       settingsFile.set(subExtension.focusSettingsFile)
-      notCompatibleWithConfigurationCache("This reads configurations from the project at action-time.")
+      modulesToDirMapFile.set(subExtension.moduleToDirMapFile)
+      projectPath.set(project.path)
+      // Collecting dependencies info in the configuration phase.
+      // Gradle disallows accessing project in execution phase.
+      projectDeps.set(project.collectDependencies())
     }
   }
 }

focus-gradle-plugin/src/main/kotlin/com/dropbox/focus/FocusSubExtension.kt

@@ -16,4 +16,7 @@ public abstract class FocusSubExtension @Inject constructor(
     layout.buildDirectory.file("focus.settings.gradle")
   )
 
+  public val moduleToDirMapFile: RegularFileProperty = objects.fileProperty().convention(
+    layout.buildDirectory.file("moduleToDirMap.csv")
+  )
 }

focus-gradle-plugin/src/test/kotlin/com/dropbox/focus/FocusPluginTest.kt

@@ -2,7 +2,6 @@ package com.dropbox.focus
 
 import com.google.common.truth.Truth.assertThat
 import java.io.File
-import java.time.temporal.Temporal
 import org.gradle.testkit.runner.BuildResult
 import org.gradle.testkit.runner.GradleRunner
 import org.junit.Before
@@ -22,7 +21,24 @@ class FocusPluginTest {
   }
 
   @Test
-  fun configurationCache() {
+  fun configurationCache_focus() {
+    val fixtureRoot = File("src/test/projects/configuration-cache-compatible")
+
+    gradleRunner
+      .withArguments("--configuration-cache", "focus")
+      .withProjectDir(fixtureRoot)
+      .build()
+
+    val result = gradleRunner
+      .withArguments("--configuration-cache", "focus")
+      .withProjectDir(fixtureRoot)
+      .build()
+
+    assertThat(result.output).contains("Reusing configuration cache.")
+  }
+
+  @Test
+  fun configurationCache_clear() {
     val fixtureRoot = File("src/test/projects/configuration-cache-compatible")
 
     gradleRunner
@@ -51,17 +67,31 @@ class FocusPluginTest {
   }
 
   @Test
-  fun singleQuotePath() {
-    val fixtureRoot = File("src/test/projects/single-quote-path")
+  fun happyPath_CsvCreated() {
+    val fixtureRoot = File("src/test/projects/happy-path")
 
     gradleRunner
       .withArguments(":module:focus")
       .runFixture(fixtureRoot) { build() }
 
-    val focusFileContent = File("src/test/projects/single-quote-path/build/notnowhere/build/focus.settings.gradle").readText()
+    val csvFileContents = File("src/test/projects/happy-path/build/notnowhere/build/moduleToDirMap.csv").readText()
     val absoluteFilePath = fixtureRoot.resolve("build/notnowhere").absolutePath.replace("\\", "\\\\")
+    // language=csv
+    assertThat(csvFileContents).contains(""":module,$absoluteFilePath""")
+  }
+
+  @Test
+  fun happyPath_CsvRead() {
+    val fixtureRoot = File("src/test/projects/happy-path")
+
+    gradleRunner
+      .withArguments(":module:focus")
+      .runFixture(fixtureRoot) { build() }
+
+    val csvFilePath = File("src/test/projects/happy-path/build/notnowhere/build/moduleToDirMap.csv").absolutePath
+    val focusFileContent = File("src/test/projects/happy-path/build/notnowhere/build/focus.settings.gradle").readText()
     // language=groovy
-    assertThat(focusFileContent).contains("""project(":module").projectDir = new File('$absoluteFilePath')""")
+    assertThat(focusFileContent).contains("""File f = new File("$csvFilePath")""")
   }
 
   private fun GradleRunner.runFixture(