Refactor bom generation

plugins/src/main/java/com/google/firebase/gradle/bomgenerator/GenerateBomReleaseNotesTask.kt

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.gradle.bomgenerator
+
+import com.google.firebase.gradle.plugins.createIfAbsent
+import com.google.firebase.gradle.plugins.datamodels.ArtifactDependency
+import com.google.firebase.gradle.plugins.datamodels.PomElement
+import com.google.firebase.gradle.plugins.datamodels.fullArtifactName
+import org.gradle.api.DefaultTask
+import org.gradle.api.file.RegularFileProperty
+import org.gradle.api.provider.MapProperty
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.InputFile
+import org.gradle.api.tasks.Internal
+import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.TaskAction
+
+/**
+ * Generates the release notes for a bom.
+ *
+ * @see GenerateBomTask
+ */
+abstract class GenerateBomReleaseNotesTask : DefaultTask() {
+  @get:InputFile abstract val currentBom: RegularFileProperty
+
+  @get:Input abstract val previousBom: Property<PomElement>
+
+  @get:OutputFile abstract val releaseNotesFile: RegularFileProperty
+
+  @get:Internal abstract val previousBomVersions: MapProperty<String, String?>
+
+  @TaskAction
+  fun generate() {
+    val bom = PomElement.fromFile(currentBom.asFile.get())
+    val currentDeps = bom.dependencyManagement?.dependencies.orEmpty()
+    val previousDeps = previousBom.get().dependencyManagement?.dependencies.orEmpty()
+    previousBomVersions.set(previousDeps.associate { it.fullArtifactName to it.version })
+
+    val sortedDependencies = currentDeps.sortedBy { it.version }
+
+    val headingId = "{: #bom_v${bom.version.replace(".", "-")}}"
+
+    releaseNotesFile.asFile
+      .get()
+      .createIfAbsent()
+      .writeText(
+        """
+         |### {{firebase_bom_long}} ({{bill_of_materials}}) version ${bom.version} $headingId
+         |{% comment %}
+         |These library versions must be flat-typed, do not use variables.
+         |The release note for this BoM version is a library-version snapshot.
+         |{% endcomment %}
+         |
+         |<section class="expandable">
+         |  <p class="showalways">
+         |    Firebase Android SDKs mapped to this {{bom}} version
+         |  </p>
+         |  <p>
+         |    Libraries that were versioned with this release are in highlighted rows.<br>
+         |    Refer to a library's release notes (on this page) for details about its changes.
+         |  </p>
+         |  <table>
+         |    <thead>
+         |      <th>Artifact name</th>
+         |      <th>Version mapped<br>to previous {{bom}} v${previousBom.get().version}</th>
+         |      <th>Version mapped<br>to this {{bom}} v${bom.version}</th>
+         |    </thead>
+         |    <tbody>
+         |${sortedDependencies.joinToString("\n") { artifactToListEntry(it) }.prependIndent("      ")}
+         |    </tbody>
+         |  </table>
+         |</section>
+         |
+        """
+          .trimMargin()
+      )
+  }
+
+  private fun artifactToListEntry(artifact: ArtifactDependency): String {
+    val previousVersion = previousBomVersions.get()[artifact.fullArtifactName] ?: "N/A"
+    val artifactName = "${artifact.groupId}:${artifact.artifactId}"
+
+    return if (artifact.version != previousVersion) {
+      """
+       |<tr class="alt">
+       |  <td><b>${artifactName}</b></td>
+       |  <td><b>$previousVersion</b></td>
+       |  <td><b>${artifact.version}</b></td>
+       |</tr>
+      """
+        .trimMargin()
+    } else {
+      """
+       |<tr>
+       |  <td>${artifactName}</td>
+       |  <td>$previousVersion</td>
+       |  <td>${artifact.version}</td>
+       |</tr>
+      """
+        .trimMargin()
+    }
+  }
+}

plugins/src/main/java/com/google/firebase/gradle/bomgenerator/GenerateBomTask.kt

@@ -0,0 +1,221 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.gradle.bomgenerator
+
+import com.google.firebase.gradle.plugins.ModuleVersion
+import com.google.firebase.gradle.plugins.VersionType
+import com.google.firebase.gradle.plugins.createIfAbsent
+import com.google.firebase.gradle.plugins.datamodels.ArtifactDependency
+import com.google.firebase.gradle.plugins.datamodels.DependencyManagementElement
+import com.google.firebase.gradle.plugins.datamodels.LicenseElement
+import com.google.firebase.gradle.plugins.datamodels.PomElement
+import com.google.firebase.gradle.plugins.datamodels.fullArtifactName
+import com.google.firebase.gradle.plugins.datamodels.moduleVersion
+import com.google.firebase.gradle.plugins.diff
+import com.google.firebase.gradle.plugins.orEmpty
+import com.google.firebase.gradle.plugins.partitionNotNull
+import com.google.firebase.gradle.plugins.services.GMavenService
+import org.gradle.api.DefaultTask
+import org.gradle.api.file.DirectoryProperty
+import org.gradle.api.provider.ListProperty
+import org.gradle.api.provider.MapProperty
+import org.gradle.api.provider.Property
+import org.gradle.api.services.ServiceReference
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.OutputDirectory
+import org.gradle.api.tasks.TaskAction
+
+/**
+ * Generates the firebase bom, using gmaven as a source of truth for artifacts and versions.
+ *
+ * @see validateArtifacts
+ * @see GenerateBomReleaseNotesTask
+ * @see GenerateTutorialBundleTask
+ */
+abstract class GenerateBomTask : DefaultTask() {
+  /**
+   * Artifacts to include in the bom.
+   *
+   * ```
+   * bomArtifacts.set(listOf(
+   *   "com.google.firebase:firebase-firestore",
+   *   "com.google.firebase:firebase-storage"
+   * ))
+   * ```
+   */
+  @get:Input abstract val bomArtifacts: ListProperty<String>
+
+  /**
+   * Artifacts to exclude from the bom.
+   *
+   * These are artifacts that are under the `com.google.firebase` namespace, but are intentionally
+   * not included in the bom.
+   *
+   * ```
+   * bomArtifacts.set(listOf(
+   *   "com.google.firebase:crashlytics",
+   *   "com.google.firebase:crash-plugin"
+   * ))
+   * ```
+   */
+  @get:Input abstract val ignoredArtifacts: ListProperty<String>
+
+  /**
+   * Optional map of versions to use instead of the versions on gmaven.
+   *
+   * ```
+   * versionOverrides.set(mapOf(
+   *   "com.google.firebase:firebase-firestore" to "10.0.0"
+   * ))
+   * ```
+   */
+  @get:Input abstract val versionOverrides: MapProperty<String, String>
+
+  /** Directory to save the bom under. */
+  @get:OutputDirectory abstract val outputDirectory: DirectoryProperty
+
+  @get:ServiceReference("gmaven") abstract val gmaven: Property<GMavenService>
+
+  @TaskAction
+  fun generate() {
+    val versionOverrides = versionOverrides.getOrElse(emptyMap())
+
+    val validatedArtifactsToPublish = validateArtifacts()
+    val artifactsToPublish =
+      validatedArtifactsToPublish.map {
+        val version = versionOverrides[it.fullArtifactName] ?: it.version
+        logger.debug("Using ${it.fullArtifactName} with version $version")
+
+        it.copy(version = version)
+      }
+
+    val newVersion = determineNewBomVersion(artifactsToPublish)
+
+    val pom =
+      PomElement(
+        namespace = "http://maven.apache.org/POM/4.0.0",
+        schema = "http://www.w3.org/2001/XMLSchema-instance",
+        schemaLocation =
+          "http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd",
+        modelVersion = "4.0.0",
+        groupId = "com.google.firebase",
+        artifactId = "firebase-bom",
+        version = newVersion.toString(),
+        packaging = "pom",
+        licenses =
+          listOf(
+            LicenseElement(
+              name = "The Apache Software License, Version 2.0",
+              url = "http://www.apache.org/licenses/LICENSE-2.0.txt",
+              distribution = "repo",
+            )
+          ),
+        dependencyManagement = DependencyManagementElement(artifactsToPublish),
+      )
+
+    val bomFile =
+      outputDirectory.file(
+        "com/google/firebase/firebase-bom/$newVersion/firebase-bom-$newVersion.pom"
+      )
+
+    pom.toFile(bomFile.get().asFile.createIfAbsent())
+  }
+
+  private fun determineNewBomVersion(
+    releasingDependencies: List<ArtifactDependency>
+  ): ModuleVersion {
+    logger.info("Determining the new bom version")
+
+    val oldBom = gmaven.get().latestPom("com.google.firebase", "firebase-bom")
+    val oldBomVersion = ModuleVersion.fromString(oldBom.artifactId, oldBom.version)
+
+    val oldBomDependencies = oldBom.dependencyManagement?.dependencies.orEmpty()
+    val changedDependencies = oldBomDependencies.diff(releasingDependencies)
+
+    val versionBumps =
+      changedDependencies.mapNotNull { (old, new) ->
+        if (old == null) {
+          logger.warn("Dependency was added: ${new?.fullArtifactName}")
+
+          VersionType.MINOR
+        } else if (new === null) {
+          logger.warn("Dependency was removed: ${old.fullArtifactName}")
+
+          VersionType.MAJOR
+        } else {
+          old.moduleVersion.bumpFrom(new.moduleVersion)
+        }
+      }
+
+    val finalBump = versionBumps.minOrNull()
+    return oldBomVersion.bump(finalBump)
+  }
+
+  /**
+   * Validates that the provided bom artifacts satisfy the following constraints:
+   * - All are released and live on gmaven.
+   * - They include _all_ of the firebase artifacts on gmaven, unless they're specified in
+   *   [ignoredArtifacts].+
+   *
+   * @return The validated artifacts to release.
+   * @throws RuntimeException If any of the validations fail.
+   */
+  private fun validateArtifacts(): List<ArtifactDependency> {
+    logger.info("Validating bom artifacts")
+
+    val firebaseArtifacts = bomArtifacts.get().toSet()
+    val ignoredArtifacts = ignoredArtifacts.orEmpty().toSet()
+
+    val allFirebaseArtifacts =
+      gmaven
+        .get()
+        .groupIndex("com.google.firebase")
+        .map { "${it.groupId}:${it.artifactId}" }
+        .toSet()
+
+    val (released, unreleased) =
+      firebaseArtifacts
+        .associateWith { gmaven.get().groupIndexArtifactOrNull(it) }
+        .partitionNotNull()
+
+    if (unreleased.isNotEmpty()) {
+      throw RuntimeException(
+        """
+          |Some artifacts required for bom generation are not live on gmaven yet:
+          |${unreleased.joinToString("\n")}
+        """
+          .trimMargin()
+      )
+    }
+
+    val requiredArtifacts = allFirebaseArtifacts - ignoredArtifacts
+    val missingArtifacts = requiredArtifacts - firebaseArtifacts
+    if (missingArtifacts.isNotEmpty()) {
+      throw RuntimeException(
+        """
+          |There are Firebase artifacts missing from the provided bom artifacts.
+          |Add the artifacts to the ignoredArtifacts property to ignore them or to the bomArtifacts property to include them in the bom.
+          |Dependencies missing:
+          |${missingArtifacts.joinToString("\n")}
+        """
+          .trimMargin()
+      )
+    }
+
+    return released.values.map { it.toArtifactDependency() }
+  }
+}