perf: improve resolver cache hit rate (#481)

Author: 3ru

lib/ResolverFactory.js

@@ -392,22 +392,7 @@ module.exports.createResolver = function createResolver(options) {
 		{ source: "resolve", resolveOptions: { fullySpecified } },
 		{ source: "internal-resolve", resolveOptions: { fullySpecified: false } },
 	]) {
-		if (unsafeCache) {
-			plugins.push(
-				new UnsafeCachePlugin(
-					source,
-					cachePredicate,
-					/** @type {import("./UnsafeCachePlugin").Cache} */ (unsafeCache),
-					cacheWithContext,
-					`new-${source}`,
-				),
-			);
-			plugins.push(
-				new ParsePlugin(`new-${source}`, resolveOptions, "parsed-resolve"),
-			);
-		} else {
-			plugins.push(new ParsePlugin(source, resolveOptions, "parsed-resolve"));
-		}
+		plugins.push(new ParsePlugin(source, resolveOptions, "parsed-resolve"));
 	}
 
 	// parsed-resolve
@@ -422,7 +407,19 @@ module.exports.createResolver = function createResolver(options) {
 	plugins.push(new NextPlugin("after-parsed-resolve", "described-resolve"));
 
 	// described-resolve
-	plugins.push(new NextPlugin("described-resolve", "raw-resolve"));
+	if (unsafeCache) {
+		plugins.push(
+			new UnsafeCachePlugin(
+				"described-resolve",
+				cachePredicate,
+				/** @type {import("./UnsafeCachePlugin").Cache} */ (unsafeCache),
+				cacheWithContext,
+				"raw-resolve",
+			),
+		);
+	} else {
+		plugins.push(new NextPlugin("described-resolve", "raw-resolve"));
+	}
 	if (fallback.length > 0) {
 		plugins.push(
 			new AliasPlugin("described-resolve", fallback, "internal-resolve"),

lib/UnsafeCachePlugin.js

@@ -5,12 +5,55 @@
 
 "use strict";
 
+const { cachedJoin } = require("./util/path");
+
 /** @typedef {import("./Resolver")} Resolver */
 /** @typedef {import("./Resolver").ResolveRequest} ResolveRequest */
 /** @typedef {import("./Resolver").ResolveStepHook} ResolveStepHook */
 /** @typedef {import("./Resolver").ResolveContextYield} ResolveContextYield */
 /** @typedef {{ [k: string]: undefined | ResolveRequest | ResolveRequest[] }} Cache */
 
+const RELATIVE_REQUEST_REGEXP = /^\.\.?(?:\/|$)/;
+
+/**
+ * @param {string} relativePath relative path from package root
+ * @param {string} request relative request
+ * @returns {string} normalized request with a preserved leading dot
+ */
+function joinRelativePreservingLeadingDot(relativePath, request) {
+	const normalized = cachedJoin(relativePath, request);
+	return RELATIVE_REQUEST_REGEXP.test(normalized)
+		? normalized
+		: `./${normalized}`;
+}
+
+/**
+ * @param {ResolveRequest} request request
+ * @returns {string | false | undefined} normalized path
+ */
+function getCachePath(request) {
+	if (request.descriptionFileRoot && !request.module) {
+		return request.descriptionFileRoot;
+	}
+	return request.path;
+}
+
+/**
+ * @param {ResolveRequest} request request
+ * @returns {string | undefined} normalized request string
+ */
+function getCacheRequest(request) {
+	const requestString = request.request;
+	if (
+		!requestString ||
+		!request.relativePath ||
+		!RELATIVE_REQUEST_REGEXP.test(requestString)
+	) {
+		return requestString;
+	}
+	return joinRelativePreservingLeadingDot(request.relativePath, requestString);
+}
+
 /**
  * @param {string} type type of cache
  * @param {ResolveRequest} request request
@@ -21,10 +64,10 @@ function getCacheId(type, request, withContext) {
 	return JSON.stringify({
 		type,
 		context: withContext ? request.context : "",
-		path: request.path,
+		path: getCachePath(request),
 		query: request.query,
 		fragment: request.fragment,
-		request: request.request,
+		request: getCacheRequest(request),
 	});
 }
 
@@ -53,7 +96,15 @@ module.exports = class UnsafeCachePlugin {
 		resolver
 			.getHook(this.source)
 			.tapAsync("UnsafeCachePlugin", (request, resolveContext, callback) => {
-				if (!this.filterPredicate(request)) return callback();
+				if (!this.filterPredicate(request)) {
+					return resolver.doResolve(
+						target,
+						request,
+						null,
+						resolveContext,
+						callback,
+					);
+				}
 				const isYield = typeof resolveContext.yield === "function";
 				const cacheId = getCacheId(
 					isYield ? "yield" : "default",

test/fixtures/unsafe-cache-normalization/node_modules/react/index.js

@@ -0,0 +1,3 @@
+{
+  "name": "unsafe-cache-normalization"
+}

test/fixtures/unsafe-cache-normalization/node_modules/react/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "unsafe-cache-normalization-nested"
+}