Updated the files.

my-app/node_modules/webpack/lib/util/findGraphRoots.js

@@ -0,0 +1,231 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+const NO_MARKER = 0;
+const IN_PROGRESS_MARKER = 1;
+const DONE_MARKER = 2;
+const DONE_MAYBE_ROOT_CYCLE_MARKER = 3;
+const DONE_AND_ROOT_MARKER = 4;
+
+/**
+ * @template T
+ */
+class Node {
+	/**
+	 * @param {T} item the value of the node
+	 */
+	constructor(item) {
+		this.item = item;
+		/** @type {Set<Node<T>>} */
+		this.dependencies = new Set();
+		this.marker = NO_MARKER;
+		/** @type {Cycle<T> | undefined} */
+		this.cycle = undefined;
+		this.incoming = 0;
+	}
+}
+
+/**
+ * @template T
+ */
+class Cycle {
+	constructor() {
+		/** @type {Set<Node<T>>} */
+		this.nodes = new Set();
+	}
+}
+
+/**
+ * @template T
+ * @typedef {Object} StackEntry
+ * @property {Node<T>} node
+ * @property {Node<T>[]} openEdges
+ */
+
+/**
+ * @template T
+ * @param {Iterable<T>} items list of items
+ * @param {function(T): Iterable<T>} getDependencies function to get dependencies of an item (items that are not in list are ignored)
+ * @returns {Iterable<T>} graph roots of the items
+ */
+module.exports = (items, getDependencies) => {
+	/** @type {Map<T, Node<T>>} */
+	const itemToNode = new Map();
+	for (const item of items) {
+		const node = new Node(item);
+		itemToNode.set(item, node);
+	}
+
+	// early exit when there is only a single item
+	if (itemToNode.size <= 1) return items;
+
+	// grab all the dependencies
+	for (const node of itemToNode.values()) {
+		for (const dep of getDependencies(node.item)) {
+			const depNode = itemToNode.get(dep);
+			if (depNode !== undefined) {
+				node.dependencies.add(depNode);
+			}
+		}
+	}
+
+	// Set of current root modules
+	// items will be removed if a new reference to it has been found
+	/** @type {Set<Node<T>>} */
+	const roots = new Set();
+
+	// Set of current cycles without references to it
+	// cycles will be removed if a new reference to it has been found
+	// that is not part of the cycle
+	/** @type {Set<Cycle<T>>} */
+	const rootCycles = new Set();
+
+	// For all non-marked nodes
+	for (const selectedNode of itemToNode.values()) {
+		if (selectedNode.marker === NO_MARKER) {
+			// deep-walk all referenced modules
+			// in a non-recursive way
+
+			// start by entering the selected node
+			selectedNode.marker = IN_PROGRESS_MARKER;
+
+			// keep a stack to avoid recursive walk
+			/** @type {StackEntry<T>[]} */
+			const stack = [
+				{
+					node: selectedNode,
+					openEdges: Array.from(selectedNode.dependencies)
+				}
+			];
+
+			// process the top item until stack is empty
+			while (stack.length > 0) {
+				const topOfStack = stack[stack.length - 1];
+
+				// Are there still edges unprocessed in the current node?
+				if (topOfStack.openEdges.length > 0) {
+					// Process one dependency
+					const dependency =
+						/** @type {Node<T>} */
+						(topOfStack.openEdges.pop());
+					switch (dependency.marker) {
+						case NO_MARKER:
+							// dependency has not be visited yet
+							// mark it as in-progress and recurse
+							stack.push({
+								node: dependency,
+								openEdges: Array.from(dependency.dependencies)
+							});
+							dependency.marker = IN_PROGRESS_MARKER;
+							break;
+						case IN_PROGRESS_MARKER: {
+							// It's a in-progress cycle
+							let cycle = dependency.cycle;
+							if (!cycle) {
+								cycle = new Cycle();
+								cycle.nodes.add(dependency);
+								dependency.cycle = cycle;
+							}
+							// set cycle property for each node in the cycle
+							// if nodes are already part of a cycle
+							// we merge the cycles to a shared cycle
+							for (
+								let i = stack.length - 1;
+								stack[i].node !== dependency;
+								i--
+							) {
+								const node = stack[i].node;
+								if (node.cycle) {
+									if (node.cycle !== cycle) {
+										// merge cycles
+										for (const cycleNode of node.cycle.nodes) {
+											cycleNode.cycle = cycle;
+											cycle.nodes.add(cycleNode);
+										}
+									}
+								} else {
+									node.cycle = cycle;
+									cycle.nodes.add(node);
+								}
+							}
+							// don't recurse into dependencies
+							// these are already on the stack
+							break;
+						}
+						case DONE_AND_ROOT_MARKER:
+							// This node has be visited yet and is currently a root node
+							// But as this is a new reference to the node
+							// it's not really a root
+							// so we have to convert it to a normal node
+							dependency.marker = DONE_MARKER;
+							roots.delete(dependency);
+							break;
+						case DONE_MAYBE_ROOT_CYCLE_MARKER:
+							// This node has be visited yet and
+							// is maybe currently part of a completed root cycle
+							// we found a new reference to the cycle
+							// so it's not really a root cycle
+							// remove the cycle from the root cycles
+							// and convert it to a normal node
+							rootCycles.delete(/** @type {Cycle<T>} */ (dependency.cycle));
+							dependency.marker = DONE_MARKER;
+							break;
+						// DONE_MARKER: nothing to do, don't recurse into dependencies
+					}
+				} else {
+					// All dependencies of the current node has been visited
+					// we leave the node
+					stack.pop();
+					topOfStack.node.marker = DONE_MARKER;
+				}
+			}
+			const cycle = selectedNode.cycle;
+			if (cycle) {
+				for (const node of cycle.nodes) {
+					node.marker = DONE_MAYBE_ROOT_CYCLE_MARKER;
+				}
+				rootCycles.add(cycle);
+			} else {
+				selectedNode.marker = DONE_AND_ROOT_MARKER;
+				roots.add(selectedNode);
+			}
+		}
+	}
+
+	// Extract roots from root cycles
+	// We take the nodes with most incoming edges
+	// inside of the cycle
+	for (const cycle of rootCycles) {
+		let max = 0;
+		/** @type {Set<Node<T>>} */
+		const cycleRoots = new Set();
+		const nodes = cycle.nodes;
+		for (const node of nodes) {
+			for (const dep of node.dependencies) {
+				if (nodes.has(dep)) {
+					dep.incoming++;
+					if (dep.incoming < max) continue;
+					if (dep.incoming > max) {
+						cycleRoots.clear();
+						max = dep.incoming;
+					}
+					cycleRoots.add(dep);
+				}
+			}
+		}
+		for (const cycleRoot of cycleRoots) {
+			roots.add(cycleRoot);
+		}
+	}
+
+	// When roots were found, return them
+	if (roots.size > 0) {
+		return Array.from(roots, r => r.item);
+	} else {
+		throw new Error("Implementation of findGraphRoots is broken");
+	}
+};