From 9964a8283f86b7429e16aac8b044df6aed1ce7ad Mon Sep 17 00:00:00 2001
From: Tobias Koppers <tobias.koppers@googlemail.com>
Date: Mon, 22 Oct 2018 09:02:39 +0200
Subject: [PATCH] fix resolver cache

---
 lib/ResolverFactory.js | 40 ++++++++++++++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 8 deletions(-)

diff --git a/lib/ResolverFactory.js b/lib/ResolverFactory.js
index 3fb3a6c7a..4c70555e7 100644
--- a/lib/ResolverFactory.js
+++ b/lib/ResolverFactory.js
@@ -8,6 +8,8 @@
 const Factory = require("enhanced-resolve").ResolverFactory;
 const { HookMap, SyncHook, SyncWaterfallHook } = require("tapable");
 
+/** @typedef {import("enhanced-resolve/lib/Resolver")} Resolver */
+
 module.exports = class ResolverFactory {
 	constructor() {
 		this.hooks = Object.freeze({
@@ -16,21 +18,43 @@ module.exports = class ResolverFactory {
 			),
 			resolver: new HookMap(() => new SyncHook(["resolver", "resolveOptions"]))
 		});
-		this.cache1 = new WeakMap();
-		this.cache2 = new Map();
+		/** @type {Map<string, { direct: WeakMap<Object, Resolver>, stringified: Map<string, Resolver> }>} */
+		this.cache = new Map();
 	}
 
+	/**
+	 * @param {string} type type of resolver
+	 * @param {Object} resolveOptions options
+	 * @returns {Resolver} the resolver
+	 */
 	get(type, resolveOptions) {
-		const cachedResolver = this.cache1.get(resolveOptions);
-		if (cachedResolver) return cachedResolver();
-		const ident = `${type}|${JSON.stringify(resolveOptions)}`;
-		const resolver = this.cache2.get(ident);
-		if (resolver) return resolver;
+		let typedCaches = this.cache.get(type);
+		if (!typedCaches) {
+			typedCaches = {
+				direct: new WeakMap(),
+				stringified: new Map()
+			};
+			this.cache.set(type, typedCaches);
+		}
+		const cachedResolver = typedCaches.direct.get(resolveOptions);
+		if (cachedResolver) return cachedResolver;
+		const ident = JSON.stringify(resolveOptions);
+		const resolver = typedCaches.stringified.get(ident);
+		if (resolver) {
+			typedCaches.direct.set(resolveOptions, resolver);
+			return resolver;
+		}
 		const newResolver = this._create(type, resolveOptions);
-		this.cache2.set(ident, newResolver);
+		typedCaches.direct.set(resolveOptions, newResolver);
+		typedCaches.stringified.set(ident, newResolver);
 		return newResolver;
 	}
 
+	/**
+	 * @param {string} type type of resolver
+	 * @param {Object} resolveOptions options
+	 * @returns {Resolver} the resolver
+	 */
 	_create(type, resolveOptions) {
 		resolveOptions = this.hooks.resolveOptions.for(type).call(resolveOptions);
 		const resolver = Factory.createResolver(resolveOptions);