From 05158d2cdeb0e08cf41d0225f3fc5a6450850bf4 Mon Sep 17 00:00:00 2001
From: Zoltan Kochan <z@kochan.io>
Date: Fri, 27 Feb 2026 23:51:58 +0100
Subject: [PATCH] fix: comparison of hoistPattern values (#10713)

---
 .changeset/slick-cases-double.md                | 6 ++++++
 pkg-manager/core/src/install/validateModules.ts | 4 ++--
 pkg-manager/headless/src/index.ts               | 4 ++--
 3 files changed, 10 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/slick-cases-double.md

diff --git a/.changeset/slick-cases-double.md b/.changeset/slick-cases-double.md
new file mode 100644
index 0000000000..7a4cc64ce5
--- /dev/null
+++ b/.changeset/slick-cases-double.md
@@ -0,0 +1,6 @@
+---
+"@pnpm/headless": patch
+"@pnpm/core": patch
+---
+
+Fix the comparison of current and previous hoistPattern and publicHoistPattern values.
diff --git a/pkg-manager/core/src/install/validateModules.ts b/pkg-manager/core/src/install/validateModules.ts
index c8cbfab1d9..b790402888 100644
--- a/pkg-manager/core/src/install/validateModules.ts
+++ b/pkg-manager/core/src/install/validateModules.ts
@@ -63,7 +63,7 @@ export async function validateModules (
   }
   if (
     opts.forcePublicHoistPattern &&
-    !equals(modules.publicHoistPattern, opts.publicHoistPattern || undefined)
+    !equals(modules.publicHoistPattern ?? [], opts.publicHoistPattern ?? [])
   ) {
     if (opts.forceNewModules && (rootProject != null)) {
       await purgeModulesDirsOfImporter(opts, rootProject)
@@ -80,7 +80,7 @@ export async function validateModules (
 
   if (opts.forceHoistPattern && (rootProject != null)) {
     try {
-      if (!equals(opts.currentHoistPattern, opts.hoistPattern || undefined)) {
+      if (!equals(opts.currentHoistPattern ?? [], opts.hoistPattern ?? [])) {
         throw new PnpmError(
           'HOIST_PATTERN_DIFF',
           'This modules directory was created using a different hoist-pattern value.' +
diff --git a/pkg-manager/headless/src/index.ts b/pkg-manager/headless/src/index.ts
index 701822d565..01bce59a6f 100644
--- a/pkg-manager/headless/src/index.ts
+++ b/pkg-manager/headless/src/index.ts
@@ -334,8 +334,8 @@ export async function headlessInstall (opts: HeadlessOptions): Promise<Installat
     nodeVersion: opts.currentEngine.nodeVersion,
     pnpmVersion: opts.currentEngine.pnpmVersion,
     supportedArchitectures: opts.supportedArchitectures,
-    includeUnchangedDeps: (!equals(opts.currentHoistPattern, opts.hoistPattern ?? undefined)) ||
-      (!equals(opts.currentPublicHoistPattern, opts.publicHoistPattern ?? undefined)),
+    includeUnchangedDeps: (!equals(opts.currentHoistPattern ?? [], opts.hoistPattern ?? [])) ||
+      (!equals(opts.currentPublicHoistPattern ?? [], opts.publicHoistPattern ?? [])),
   } as LockfileToDepGraphOptions
   const {
     directDependenciesByImporterId,