From cfa26190df4da614c5b132af84a9d4f54ccda943 Mon Sep 17 00:00:00 2001
From: Raymond Cohen <rcohen@squareup.com>
Date: Thu, 21 Sep 2023 17:36:17 -0400
Subject: [PATCH] cache realpathSync access in package-cache.get

---
 packages/shared-internals/src/package-cache.ts | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/packages/shared-internals/src/package-cache.ts b/packages/shared-internals/src/package-cache.ts
index c679cd929..8669227e6 100644
--- a/packages/shared-internals/src/package-cache.ts
+++ b/packages/shared-internals/src/package-cache.ts
@@ -4,6 +4,19 @@ import { getOrCreate } from './get-or-create';
 import resolvePackagePath from 'resolve-package-path';
 import { dirname, sep } from 'path';
 
+const realpathSyncCache = new Map<string, string>();
+
+function getCachedRealpath(path: string): string {
+  let cached = realpathSyncCache.get(path);
+  if (cached) {
+    return cached;
+  }
+
+  let root = realpathSync(path);
+  realpathSyncCache.set(path, root);
+  return root;
+}
+
 export default class PackageCache {
   constructor(public appRoot: string) {}
 
@@ -31,7 +44,7 @@ export default class PackageCache {
   private resolutionCache: Map<Package, Map<string, Package | null>> = new Map();
 
   get(packageRoot: string) {
-    let root = realpathSync(packageRoot);
+    let root = getCachedRealpath(packageRoot);
     let p = getOrCreate(this.rootCache, root, () => {
       return new Package(root, this, root === this.appRoot);
     });