Implement a task for updating changelog files after a release

buildSrc/src/main/java/com/google/firebase/gradle/plugins/Changelog.kt

@@ -27,6 +27,9 @@ import java.io.File
  * @see fromString
  */
 data class Changelog(val releases: List<ReleaseEntry>) {
+
+  override fun toString(): String = releases.joinToString("\n") + "\n"
+
   companion object {
     /**
      * Regex for finding the version titles in a changelog file.
@@ -114,7 +117,41 @@ data class ReleaseEntry(
   val content: ReleaseContent,
   val ktx: ReleaseContent?
 ) {
+
+  override fun toString(): String {
+    return """
+      |# ${version ?: "Unreleased"}
+      |$content
+      |${ktx?.let { """
+      |
+      |## Kotlin
+      |$it
+      |""" }.orEmpty()}
+    """
+      .trimMargin()
+  }
+
+  /**
+   * If there is any content in this release.
+   *
+   * Meaning that there is content in either the [base release][content] or [ktx].
+   *
+   * @see ReleaseContent.hasContent
+   */
+  fun hasContent() = content.hasContent() || ktx?.hasContent() ?: false
+
   companion object {
+
+    /**
+     * A static instance of a [ReleaseEntry] without any content.
+     *
+     * This exists to provide a means for tooling to create new sections explicitly, versus offering
+     * default values to [ReleaseEntry]
+     * - as this could lead to edge case scenarios where empty [ReleaseEntry] instances are
+     * accidentally created.
+     */
+    val Empty = ReleaseEntry(null, ReleaseContent("", emptyList()), null)
+
     /**
      * Regex for finding the Kotlin header in a changelog file.
      *
@@ -164,18 +201,12 @@ data class ReleaseEntry(
       val ktx = ktxString?.let { ReleaseContent.fromString(it) }
       val version = ModuleVersion.fromStringOrNull(versionString)
 
+      if (ktx?.hasContent() == false)
+        throw RuntimeException("KTX header found without any content:\n $string")
+
       return ReleaseEntry(version, content, ktx)
     }
   }
-
-  /**
-   * If there is any content in this release.
-   *
-   * Meaning that there is content in either the [base release][content] or [ktx].
-   *
-   * @see ReleaseContent.hasContent
-   */
-  fun hasContent() = content.hasContent() || ktx?.hasContent() ?: false
 }
 
 /**
@@ -186,6 +217,25 @@ data class ReleaseEntry(
  * @see fromString
  */
 data class ReleaseContent(val subtext: String, val changes: List<Change>) {
+
+  override fun toString(): String {
+    val changes = changes.joinToString("\n")
+
+    return when {
+      subtext.isNotBlank() && changes.isNotBlank() -> "$subtext\n\n$changes"
+      subtext.isNotBlank() -> subtext
+      changes.isNotBlank() -> changes
+      else -> ""
+    }
+  }
+
+  /**
+   * If there is any content in this release.
+   *
+   * Meaning that there is either [changes] or [subtext] present.
+   */
+  fun hasContent() = changes.isNotEmpty() || subtext.isNotBlank()
+
   companion object {
     /**
      * Regex for finding the changes in a release.
@@ -235,7 +285,7 @@ data class ReleaseContent(val subtext: String, val changes: List<Change>) {
      * "This release contains a known bug. We will address this in a future bugfix."
      * ```
      */
-    val SUBTEXT_REGEX = Regex("^([^\\*\\s][\\s\\S]+?)(\\n\\n|(?![\\s\\S]))", RegexOption.MULTILINE)
+    val SUBTEXT_REGEX = Regex("^([^\\*\\s][\\s\\S]+?)(\\n\\n|(?![\\s\\S]))")
 
     /**
      * Parses [ReleaseContent] from a [String].
@@ -254,19 +304,14 @@ data class ReleaseContent(val subtext: String, val changes: List<Change>) {
      * @see Change
      */
     fun fromString(string: String): ReleaseContent {
-      val subtext = SUBTEXT_REGEX.find(string)?.value.orEmpty().trim()
-      val changes = CHANGE_REGEX.findAll(string).map { Change.fromString(it.firstCapturedValue) }
+      val changes =
+        CHANGE_REGEX.findAll(string).map { Change.fromString(it.firstCapturedValue) }.toList()
+      val firstChange = CHANGE_REGEX.find(string)
+      val subtext = if (firstChange != null) string.substringBefore(firstChange.value) else string
 
-      return ReleaseContent(subtext, changes.toList())
+      return ReleaseContent(subtext.trim(), changes.toList())
     }
   }
-
-  /**
-   * If there is any content in this release.
-   *
-   * Meaning that there is either [changes] or [subtext] present.
-   */
-  fun hasContent() = changes.isNotEmpty() || subtext.isNotBlank()
 }
 
 /**
@@ -277,6 +322,9 @@ data class ReleaseContent(val subtext: String, val changes: List<Change>) {
  * @see fromString
  */
 data class Change(val type: ChangeType, val message: String) {
+
+  override fun toString(): String = "* [$type] $message"
+
   companion object {
     /**
      * Regex for finding the information about a [Change].
@@ -331,5 +379,7 @@ enum class ChangeType {
   CHANGED,
   UNCHANGED,
   REMOVED,
-  DEPRECATED
+  DEPRECATED;
+
+  override fun toString(): String = name.toLowerCase()
 }

buildSrc/src/main/java/com/google/firebase/gradle/plugins/GradleUtils.kt

@@ -109,6 +109,25 @@ fun DefaultTask.tempFile(path: String) = provider { temporaryDir.childFile(path)
  */
 fun File.listFilesOrEmpty() = listFiles().orEmpty()
 
+/**
+ * Copies this file to the specified directory.
+ *
+ * The new file will retain the same [name][File.getName] and [extension][File.extension] as this
+ * file.
+ *
+ * @param target The directory to copy the file to.
+ * @param overwrite Whether to overwrite the file if it already exists.
+ * @param bufferSize The size of the buffer to use for the copy operation.
+ * @return The new file.
+ *
+ * @see copyTo
+ */
+fun File.copyToDirectory(
+  target: File,
+  overwrite: Boolean = false,
+  bufferSize: Int = DEFAULT_BUFFER_SIZE
+): File = copyTo(target.childFile(name), overwrite, bufferSize)
+
 /**
  * Submits a piece of work to be executed asynchronously.
  *

buildSrc/src/main/java/com/google/firebase/gradle/plugins/MakeReleaseNotesTask.kt

@@ -97,7 +97,7 @@ abstract class MakeReleaseNotesTask : DefaultTask() {
       """
           |#### ${metadata.name} Kotlin extensions version $version {: #${metadata.versionName}-ktx_v$versionClassifier}
           |
-          |${unreleased.ktx?.toReleaseNotes() ?: KotlinTransitiveRelease(project.name)}
+          |${unreleased.ktx?.toReleaseNotes() ?: KTXTransitiveReleaseText(project.name)}
         """
         .trimMargin()
         .trim()
@@ -115,32 +115,6 @@ abstract class MakeReleaseNotesTask : DefaultTask() {
     releaseNotesFile.asFile.get().writeText(releaseNotes)
   }
 
-  /**
-   * Provides default text for releasing KTX libs that are transitively invoked in a release,
-   * because their parent module is releasing. This only applies to `-ktx` libs, not Kotlin SDKs.
-   */
-  private fun KotlinTransitiveRelease(projectName: String) =
-    """
-      |The Kotlin extensions library transitively includes the updated
-      |`${ProjectNameToKTXPlaceholder(projectName)}` library. The Kotlin extensions library has no additional
-      |updates.
-    """
-      .trimMargin()
-      .trim()
-
-  /**
-   * Maps a project's name to a KTX suitable placeholder.
-   *
-   * Some libraries produce artifacts with different coordinates than their project name. This
-   * method helps to map that gap for [KotlinTransitiveRelease].
-   */
-  private fun ProjectNameToKTXPlaceholder(projectName: String) =
-    when (projectName) {
-      "firebase-perf" -> "firebase-performance"
-      "firebase-appcheck" -> "firebase-appcheck"
-      else -> projectName
-    }
-
   /**
    * Converts a [ReleaseContent] to a [String] to be used in a release note.
    *
@@ -174,55 +148,6 @@ abstract class MakeReleaseNotesTask : DefaultTask() {
     return "* {{${type.name.toLowerCase()}}} $fixedMessage"
   }
 
-  /**
-   * Maps the name of a project to its potential [ReleaseNotesMetadata].
-   *
-   * @throws StopActionException If a mapping is not found
-   */
-  // TODO() - Should we expose these as firebaselib configuration points; especially for new SDKS?
-  private fun convertToMetadata(string: String) =
-    when (string) {
-      "firebase-abt" -> ReleaseNotesMetadata("{{ab_testing}}", "ab_testing", false)
-      "firebase-appdistribution" -> ReleaseNotesMetadata("{{appdistro}}", "app-distro", false)
-      "firebase-appdistribution-api" -> ReleaseNotesMetadata("{{appdistro}} API", "app-distro-api")
-      "firebase-config" -> ReleaseNotesMetadata("{{remote_config}}", "remote-config")
-      "firebase-crashlytics" -> ReleaseNotesMetadata("{{crashlytics}}", "crashlytics")
-      "firebase-crashlytics-ndk" ->
-        ReleaseNotesMetadata("{{crashlytics}} NDK", "crashlytics-ndk", false)
-      "firebase-database" -> ReleaseNotesMetadata("{{database}}", "realtime-database")
-      "firebase-dynamic-links" -> ReleaseNotesMetadata("{{ddls}}", "dynamic-links")
-      "firebase-firestore" -> ReleaseNotesMetadata("{{firestore}}", "firestore")
-      "firebase-functions" -> ReleaseNotesMetadata("{{functions_client}}", "functions-client")
-      "firebase-dynamic-module-support" ->
-        ReleaseNotesMetadata(
-          "Dynamic feature modules support",
-          "dynamic-feature-modules-support",
-          false
-        )
-      "firebase-inappmessaging" -> ReleaseNotesMetadata("{{inappmessaging}}", "inappmessaging")
-      "firebase-inappmessaging-display" ->
-        ReleaseNotesMetadata("{{inappmessaging}} Display", "inappmessaging-display")
-      "firebase-installations" ->
-        ReleaseNotesMetadata("{{firebase_installations}}", "installations")
-      "firebase-messaging" -> ReleaseNotesMetadata("{{messaging_longer}}", "messaging")
-      "firebase-messaging-directboot" ->
-        ReleaseNotesMetadata("Cloud Messaging Direct Boot", "messaging-directboot", false)
-      "firebase-ml-modeldownloader" ->
-        ReleaseNotesMetadata("{{firebase_ml}}", "firebaseml-modeldownloader")
-      "firebase-perf" -> ReleaseNotesMetadata("{{perfmon}}", "performance")
-      "firebase-storage" -> ReleaseNotesMetadata("{{firebase_storage_full}}", "storage")
-      "firebase-appcheck" -> ReleaseNotesMetadata("{{app_check}}", "appcheck")
-      "firebase-appcheck-debug" ->
-        ReleaseNotesMetadata("{{app_check}} Debug", "appcheck-debug", false)
-      "firebase-appcheck-debug-testing" ->
-        ReleaseNotesMetadata("{{app_check}} Debug Testing", "appcheck-debug-testing", false)
-      "firebase-appcheck-playintegrity" ->
-        ReleaseNotesMetadata("{{app_check}} Play integrity", "appcheck-playintegrity", false)
-      "firebase-appcheck-safetynet" ->
-        ReleaseNotesMetadata("{{app_check}} SafetyNet", "appcheck-safetynet", false)
-      else -> throw StopActionException("No metadata mapping found for project: $string")
-    }
-
   companion object {
     /**
      * Regex for GitHub issue links in change messages.
@@ -268,20 +193,3 @@ abstract class MakeReleaseNotesTask : DefaultTask() {
       )
   }
 }
-
-/**
- * Provides extra metadata needed to create release notes for a given project.
- *
- * This data is needed for g3 internal mappings, and does not really have any implications for
- * public repo actions.
- *
- * @property name The variable name for a project in a release note
- * @property vesionName The variable name given to the versions of a project
- * @property hasKTX The module has a KTX submodule (not to be confused with having KTX files)
- * @see MakeReleaseNotesTask
- */
-data class ReleaseNotesMetadata(
-  val name: String,
-  val versionName: String,
-  val hasKTX: Boolean = true
-)