source: frontend/node_modules/webpack/lib/container/HoistContainerReferencesPlugin.js

/*
        MIT License http://www.opensource.org/licenses/mit-license.php
        Author Zackary Jackson @ScriptedAlchemy
*/

"use strict";

const AsyncDependenciesBlock = require("../AsyncDependenciesBlock");
const ExternalModule = require("../ExternalModule");
const { STAGE_ADVANCED } = require("../OptimizationStages");
const memoize = require("../util/memoize");
const { forEachRuntime } = require("../util/runtime");

/** @typedef {import("../Compilation")} Compilation */
/** @typedef {import("../Compiler")} Compiler */
/** @typedef {import("../Dependency")} Dependency */
/** @typedef {import("../Module")} Module */

const getModuleFederationPlugin = memoize(() =>
        require("./ModuleFederationPlugin")
);

const PLUGIN_NAME = "HoistContainerReferences";

/**
 * This class is used to hoist container references in the code.
 */
class HoistContainerReferences {
        /**
         * Apply the plugin to the compiler.
         * @param {Compiler} compiler The webpack compiler instance.
         */
        apply(compiler) {
                compiler.hooks.thisCompilation.tap(PLUGIN_NAME, (compilation) => {
                        const hooks =
                                getModuleFederationPlugin().getCompilationHooks(compilation);
                        /** @type {Set<Dependency>} */
                        const depsToTrace = new Set();
                        /** @type {Set<Dependency>} */
                        const entryExternalsToHoist = new Set();
                        hooks.addContainerEntryDependency.tap(PLUGIN_NAME, (dep) => {
                                depsToTrace.add(dep);
                        });
                        hooks.addFederationRuntimeDependency.tap(PLUGIN_NAME, (dep) => {
                                depsToTrace.add(dep);
                        });

                        compilation.hooks.addEntry.tap(PLUGIN_NAME, (entryDep) => {
                                if (entryDep.type === "entry") {
                                        entryExternalsToHoist.add(entryDep);
                                }
                        });

                        // Hook into the optimizeChunks phase
                        compilation.hooks.optimizeChunks.tap(
                                {
                                        name: PLUGIN_NAME,
                                        // advanced stage is where SplitChunksPlugin runs.
                                        stage: STAGE_ADVANCED + 1
                                },
                                (_chunks) => {
                                        this.hoistModulesInChunks(
                                                compilation,
                                                depsToTrace,
                                                entryExternalsToHoist
                                        );
                                }
                        );
                });
        }

        /**
         * Hoist modules in chunks.
         * @param {Compilation} compilation The webpack compilation instance.
         * @param {Set<Dependency>} depsToTrace Set of container entry dependencies.
         * @param {Set<Dependency>} entryExternalsToHoist Set of container entry dependencies to hoist.
         */
        hoistModulesInChunks(compilation, depsToTrace, entryExternalsToHoist) {
                const { chunkGraph, moduleGraph } = compilation;

                // loop over entry points
                for (const dep of entryExternalsToHoist) {
                        const entryModule = moduleGraph.getModule(dep);
                        if (!entryModule) continue;
                        // get all the external module types and hoist them to the runtime chunk, this will get RemoteModule externals
                        const allReferencedModules = getAllReferencedModules(
                                compilation,
                                entryModule,
                                "external",
                                false
                        );

                        const containerRuntimes = chunkGraph.getModuleRuntimes(entryModule);
                        /** @type {Set<string>} */
                        const runtimes = new Set();

                        for (const runtimeSpec of containerRuntimes) {
                                forEachRuntime(runtimeSpec, (runtimeKey) => {
                                        if (runtimeKey) {
                                                runtimes.add(runtimeKey);
                                        }
                                });
                        }

                        for (const runtime of runtimes) {
                                const runtimeChunk = compilation.namedChunks.get(runtime);
                                if (!runtimeChunk) continue;

                                for (const module of allReferencedModules) {
                                        if (!chunkGraph.isModuleInChunk(module, runtimeChunk)) {
                                                chunkGraph.connectChunkAndModule(runtimeChunk, module);
                                        }
                                }
                        }
                        this.cleanUpChunks(compilation, allReferencedModules);
                }

                // handle container entry specifically
                for (const dep of depsToTrace) {
                        const containerEntryModule = moduleGraph.getModule(dep);
                        if (!containerEntryModule) continue;
                        const allReferencedModules = getAllReferencedModules(
                                compilation,
                                containerEntryModule,
                                "initial",
                                false
                        );

                        const allRemoteReferences = getAllReferencedModules(
                                compilation,
                                containerEntryModule,
                                "external",
                                false
                        );

                        for (const remote of allRemoteReferences) {
                                allReferencedModules.add(remote);
                        }

                        const containerRuntimes =
                                chunkGraph.getModuleRuntimes(containerEntryModule);
                        /** @type {Set<string>} */
                        const runtimes = new Set();

                        for (const runtimeSpec of containerRuntimes) {
                                forEachRuntime(runtimeSpec, (runtimeKey) => {
                                        if (runtimeKey) {
                                                runtimes.add(runtimeKey);
                                        }
                                });
                        }

                        for (const runtime of runtimes) {
                                const runtimeChunk = compilation.namedChunks.get(runtime);
                                if (!runtimeChunk) continue;

                                for (const module of allReferencedModules) {
                                        if (!chunkGraph.isModuleInChunk(module, runtimeChunk)) {
                                                chunkGraph.connectChunkAndModule(runtimeChunk, module);
                                        }
                                }
                        }
                        this.cleanUpChunks(compilation, allReferencedModules);
                }
        }

        /**
         * Clean up chunks by disconnecting unused modules.
         * @param {Compilation} compilation The webpack compilation instance.
         * @param {Set<Module>} modules Set of modules to clean up.
         */
        cleanUpChunks(compilation, modules) {
                const { chunkGraph } = compilation;
                for (const module of modules) {
                        for (const chunk of chunkGraph.getModuleChunks(module)) {
                                if (!chunk.hasRuntime()) {
                                        chunkGraph.disconnectChunkAndModule(chunk, module);
                                        if (
                                                chunkGraph.getNumberOfChunkModules(chunk) === 0 &&
                                                chunkGraph.getNumberOfEntryModules(chunk) === 0
                                        ) {
                                                chunkGraph.disconnectChunk(chunk);
                                                compilation.chunks.delete(chunk);
                                                if (chunk.name) {
                                                        compilation.namedChunks.delete(chunk.name);
                                                }
                                        }
                                }
                        }
                }
                modules.clear();
        }
}

/**
 * Helper method to collect all referenced modules recursively.
 * @param {Compilation} compilation The webpack compilation instance.
 * @param {Module} module The module to start collecting from.
 * @param {string} type The type of modules to collect ("initial", "external", or "all").
 * @param {boolean} includeInitial Should include the referenced module passed
 * @returns {Set<Module>} Set of collected modules.
 */
function getAllReferencedModules(compilation, module, type, includeInitial) {
        const collectedModules = new Set(includeInitial ? [module] : []);
        /** @type {WeakSet<Module>} */
        const visitedModules = new WeakSet([module]);
        /** @type {Module[]} */
        const stack = [module];

        while (stack.length > 0) {
                const currentModule = stack.pop();
                if (!currentModule) continue;

                const outgoingConnections =
                        compilation.moduleGraph.getOutgoingConnections(currentModule);
                if (outgoingConnections) {
                        for (const connection of outgoingConnections) {
                                const connectedModule = connection.module;

                                // Skip if module has already been visited
                                if (!connectedModule || visitedModules.has(connectedModule)) {
                                        continue;
                                }

                                // Handle 'initial' type (skipping async blocks)
                                if (type === "initial") {
                                        const parentBlock = compilation.moduleGraph.getParentBlock(
                                                /** @type {Dependency} */
                                                (connection.dependency)
                                        );
                                        if (parentBlock instanceof AsyncDependenciesBlock) {
                                                continue;
                                        }
                                }

                                // Handle 'external' type (collecting only external modules)
                                if (type === "external") {
                                        if (connection.module instanceof ExternalModule) {
                                                collectedModules.add(connectedModule);
                                        }
                                } else {
                                        // Handle 'all' or unspecified types
                                        collectedModules.add(connectedModule);
                                }

                                // Add connected module to the stack and mark it as visited
                                visitedModules.add(connectedModule);
                                stack.push(connectedModule);
                        }
                }
        }

        return collectedModules;
}

module.exports = HoistContainerReferences;