[FEATURE] ProjectBuilder: Add outputStyle option to request flat build output

lib/build/ProjectBuilder.js

@@ -4,6 +4,7 @@ import BuildLogger from "@ui5/logger/internal/loggers/Build";
 import composeProjectList from "./helpers/composeProjectList.js";
 import BuildContext from "./helpers/BuildContext.js";
 import prettyHrtime from "pretty-hrtime";
+import OutputStyleEnum from "./helpers/ProjectBuilderOutputStyle.js";
 
 /**
  * @public
@@ -24,6 +25,12 @@ class ProjectBuilder {
 	 *   Whether to create a build manifest file for the root project.
 	 *   This is currently only supported for projects of type 'library' and 'theme-library'
 	 *   No other dependencies can be included in the build result.
+	 * @property {module:@ui5/project/build/ProjectBuilderOutputStyle} [outputStyle=Default]
+	 *   Processes build results into a specific directory structure.
+	 *   "Flat" omits the project namespace and the "resources" directory. This
+	 *   is currently only supported for projects of type 'library'.
+	 *   Projects of type 'application' always result in a flat output.
+	 *   No other dependencies can be included in the build result.
 	 * @property {Array.<string>} [includedTasks=[]] List of tasks to be included
 	 * @property {Array.<string>} [excludedTasks=[]] List of tasks to be excluded.
 	 * 			If the wildcard '*' is provided, only the included tasks will be executed.
@@ -165,10 +172,13 @@ class ProjectBuilder {
 			return filterProject(projectName);
 		});
 
-		if (this._buildContext.getBuildConfig().createBuildManifest && requestedProjects.length > 1) {
-			throw new Error(
-				`It is currently not supported to request the creation of a build manifest ` +
-				`while including any dependencies into the build result`);
+		if (requestedProjects.length > 1) {
+			const {createBuildManifest} = this._buildContext.getBuildConfig();
+			if (createBuildManifest) {
+				throw new Error(
+					`It is currently not supported to request the creation of a build manifest ` +
+					`while including any dependencies into the build result`);
+			}
 		}
 
 		const projectBuildContexts = await this._createRequiredBuildContexts(requestedProjects);
@@ -360,13 +370,25 @@ class ProjectBuilder {
 		const project = projectBuildContext.getProject();
 		const taskUtil = projectBuildContext.getTaskUtil();
 		const buildConfig = this._buildContext.getBuildConfig();
+		const {createBuildManifest, outputStyle} = buildConfig;
+		// Output styles are applied only for the root project
+		const isRootProject = this._graph.getRoot().getName() === project.getName();
+
+		let readerStyle = "dist";
+		if (createBuildManifest ||
+			(isRootProject && outputStyle === OutputStyleEnum.Namespace && project.getType() === "application")) {
+			// Ensure buildtime (=namespaced) style when writing with a build manifest
+			readerStyle = "buildtime";
+		} else if (isRootProject && outputStyle === OutputStyleEnum.Flat) {
+			readerStyle = "flat";
+		}
+
 		const reader = project.getReader({
-			// Force buildtime (=namespaced) style when writing with a build manifest
-			style: taskUtil.isRootProject() && buildConfig.createBuildManifest ? "buildtime" : "dist"
+			style: readerStyle
 		});
 		const resources = await reader.byGlob("/**/*");
 
-		if (taskUtil.isRootProject() && buildConfig.createBuildManifest) {
+		if (createBuildManifest) {
 			// Create and write a build manifest metadata file
 			const {
 				default: createBuildManifest
@@ -386,6 +408,43 @@ class ProjectBuilder {
 			}
 			return target.write(resource);
 		}));
+
+		if (isRootProject &&
+			outputStyle === OutputStyleEnum.Flat &&
+			project.getType() !== "application" /* application type is with a flat source structure */) {
+			const namespace = project.getNamespace();
+			const libraryResourcesPrefix = `/resources/${namespace}/`;
+			const testResourcesPrefix = "/test-resources/";
+			const namespacedRegex = new RegExp(`/(resources|test-resources)/${namespace}`);
+			const processedResourcesSet = resources.reduce((acc, resource) => acc.add(resource.getPath()), new Set());
+
+			// If outputStyle === "Flat", then the FlatReader would have filtered
+			// some resources. We now need to get all of the available resources and
+			// do an intersection with the processed/bundled ones.
+			const defaultReader = project.getReader();
+			const defaultResources = await defaultReader.byGlob("/**/*");
+			const flatDefaultResources = defaultResources.map((resource) => ({
+				flatResource: resource.getPath().replace(namespacedRegex, ""),
+				originalPath: resource.getPath(),
+			}));
+
+			const skippedResources = flatDefaultResources.filter((resource) => {
+				return processedResourcesSet.has(resource.flatResource) === false;
+			});
+
+			skippedResources.forEach((resource) => {
+				if (resource.originalPath.startsWith(testResourcesPrefix)) {
+					this.#log.verbose(
+						`Omitting ${resource.originalPath} from build result. File is part of ${testResourcesPrefix}.`
+					);
+				} else if (!resource.originalPath.startsWith(libraryResourcesPrefix)) {
+					this.#log.warn(
+						`Omitting ${resource.originalPath} from build result. ` +
+							`File is not within project namespace '${namespace}'.`
+					);
+				}
+			});
+		}
 	}
 
 	async _executeCleanupTasks(force) {

lib/build/helpers/BuildContext.js

@@ -1,4 +1,5 @@
 import ProjectBuildContext from "./ProjectBuildContext.js";
+import OutputStyleEnum from "./ProjectBuilderOutputStyle.js";
 
 /**
  * Context of a build process
@@ -12,6 +13,7 @@ class BuildContext {
 		cssVariables = false,
 		jsdoc = false,
 		createBuildManifest = false,
+		outputStyle = OutputStyleEnum.Default,
 		includedTasks = [], excludedTasks = [],
 	} = {}) {
 		if (!graph) {
@@ -21,10 +23,12 @@ class BuildContext {
 			throw new Error(`Missing parameter 'taskRepository'`);
 		}
 
-		if (createBuildManifest && !["library", "theme-library"].includes(graph.getRoot().getType())) {
+		const rootProjectType = graph.getRoot().getType();
+
+		if (createBuildManifest && !["library", "theme-library"].includes(rootProjectType)) {
 			throw new Error(
 				`Build manifest creation is currently not supported for projects of type ` +
-				graph.getRoot().getType());
+				rootProjectType);
 		}
 
 		if (createBuildManifest && selfContained) {
@@ -33,12 +37,37 @@ class BuildContext {
 				`self-contained builds`);
 		}
 
+		if (createBuildManifest && outputStyle === OutputStyleEnum.Flat) {
+			throw new Error(
+				`Build manifest creation is not supported in conjunction with flat build output`);
+		}
+		if (outputStyle !== OutputStyleEnum.Default) {
+			if (rootProjectType === "theme-library") {
+				throw new Error(
+					`${outputStyle} build output is currently not supported` +
+						` since a theme-library almost always has more than one namespace.` +
+						`You can use only the Default build output for this project type.`
+				);
+			}
+			if (rootProjectType === "module") {
+				throw new Error(
+					`${outputStyle} build output is currently not supported` +
+						` since modules have explicit path mappings configured and no namespace concept.` +
+						`You can use only the Default build output for this project type.`
+				);
+			}
+		}
+
+
+		// Enforce boolean and default value, but do it here as we're also interested
+		// in the initial value above
 		this._graph = graph;
 		this._buildConfig = {
 			selfContained,
 			cssVariables,
 			jsdoc,
 			createBuildManifest,
+			outputStyle,
 			includedTasks,
 			excludedTasks,
 		};

lib/build/helpers/ProjectBuilderOutputStyle.js

@@ -0,0 +1,18 @@
+/**
+ * Processes build results into a specific directory structure.
+ *
+ * @public
+ * @readonly
+ * @enum {string}
+ * @property {string} Default Default directory structure for every project type.
+ *     For applications: "Flat", for libraries: "Namespace", for theme-libraries: "Namespace", etc.
+ * @property {string} Flat Omits the project namespace and the "resources" directory.
+ * @property {string} Namespace Respects project namespace and the "resources" directory.
+ *     Not applicable for projects of type 'application'.
+ * @module @ui5/project/build/ProjectBuilderOutputStyle
+ */
+export default {
+	Default: "Default",
+	Flat: "Flat",
+	Namespace: "Namespace"
+};

lib/graph/ProjectGraph.js

@@ -1,6 +1,8 @@
+import OutputStyleEnum from "../build/helpers/ProjectBuilderOutputStyle.js";
 import {getLogger} from "@ui5/logger";
 const log = getLogger("graph:ProjectGraph");
 
+
 /**
  * A rooted, directed graph representing a UI5 project, its dependencies and available extensions.
  * <br><br>
@@ -540,15 +542,21 @@ class ProjectGraph {
 	 *			This is currently only supported for projects of type 'library' and 'theme-library'
 	 * @param {Array.<string>} [parameters.includedTasks=[]] List of tasks to be included
 	 * @param {Array.<string>} [parameters.excludedTasks=[]] List of tasks to be excluded.
-	 * 			If the wildcard '*' is provided, only the included tasks will be executed.
+	 * @param {module:@ui5/project/build/ProjectBuilderOutputStyle} [parameters.outputStyle=Default]
+	 *   Processes build results into a specific directory structure.
+	 *   "Flat" omits the project namespace and the "resources" directory. This
+	 *   is currently only supported for projects of type 'library'.
+	 *   Projects of type 'application' always result in a flat output.
+	 *   No other dependencies can be included in the build result.
 	 * @returns {Promise} Promise resolving to <code>undefined</code> once build has finished
 	 */
 	async build({
 		destPath, cleanDest = false,
 		includedDependencies = [], excludedDependencies = [],
 		dependencyIncludes,
 		selfContained = false, cssVariables = false, jsdoc = false, createBuildManifest = false,
-		includedTasks = [], excludedTasks = []
+		includedTasks = [], excludedTasks = [],
+		outputStyle = OutputStyleEnum.Default
 	}) {
 		this.seal(); // Do not allow further changes to the graph
 		if (this._built) {
@@ -566,7 +574,7 @@ class ProjectGraph {
 			buildConfig: {
 				selfContained, cssVariables, jsdoc,
 				createBuildManifest,
-				includedTasks, excludedTasks,
+				includedTasks, excludedTasks, outputStyle,
 			}
 		});
 		await builder.build({