From 522f9ced7b90a1bbcdbac7949bb2ad7d8f8b8d4b Mon Sep 17 00:00:00 2001
From: Giuseppe Scrivano <gscrivan@redhat.com>
Date: Fri, 24 Apr 2026 17:06:54 +0000
Subject: [PATCH] unshare: do not cache HomeDir() when HOME is set

Only cache the user.LookupId() fallback path, not the $HOME
environment variable check.  This allows tests that set a custom
$HOME per test to work correctly, while still preserving the
performance optimization for the slow NSS/LDAP lookup path.

Closes: https://github.com/containers/container-libs/issues/787

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
---
 storage/pkg/unshare/unshare.go | 30 +++++++++++-------------------
 1 file changed, 11 insertions(+), 19 deletions(-)

diff --git a/storage/pkg/unshare/unshare.go b/storage/pkg/unshare/unshare.go
index 00f397f350..58eba5487c 100644
--- a/storage/pkg/unshare/unshare.go
+++ b/storage/pkg/unshare/unshare.go
@@ -7,26 +7,18 @@ import (
 	"sync"
 )
 
-var (
-	homeDirOnce sync.Once
-	homeDirErr  error
-	homeDir     string
-)
+var lookupHomeDir = sync.OnceValues(func() (string, error) {
+	usr, err := user.LookupId(fmt.Sprintf("%d", GetRootlessUID()))
+	if err != nil {
+		return "", fmt.Errorf("unable to resolve HOME directory: %w", err)
+	}
+	return usr.HomeDir, nil
+})
 
 // HomeDir returns the home directory for the current user.
 func HomeDir() (string, error) {
-	homeDirOnce.Do(func() {
-		home := os.Getenv("HOME")
-		if home == "" {
-			usr, err := user.LookupId(fmt.Sprintf("%d", GetRootlessUID()))
-			if err != nil {
-				homeDir, homeDirErr = "", fmt.Errorf("unable to resolve HOME directory: %w", err)
-				return
-			}
-			homeDir, homeDirErr = usr.HomeDir, nil
-			return
-		}
-		homeDir, homeDirErr = home, nil
-	})
-	return homeDir, homeDirErr
+	if home := os.Getenv("HOME"); home != "" {
+		return home, nil
+	}
+	return lookupHomeDir()
 }