From a5a709026a556be4e70db5719149e21e61a31757 Mon Sep 17 00:00:00 2001
From: NopeCharon <115794254+NopeCharon@users.noreply.github.com>
Date: Fri, 30 Oct 2026 03:53:44 +0530
Subject: [PATCH] fix(config): respect $HOME when resolving the default storage
 directory

config.NewRoot resolved the default storage and log directories through
os/user.Current. With cgo enabled (as in the release builds) that queries
the user database via getpwuid_r and ignores the $HOME environment
variable, so overriding $HOME, for example in tests or sandboxed
environments, still created ~/.modctl under the system home directory.
This was observed on aarch64-darwin, where every command, including
`modctl version`, touched the real home directory.

Resolve the home directory with os.UserHomeDir instead, which honors
$HOME (%USERPROFILE% on Windows), and fall back to os/user.Current only
when the environment variable is unset so that environments without
$HOME keep working as before.

Add unit tests for both the $HOME override and the fallback path.

Fixes #580

Signed-off-by: NopeCharon <115794254+NopeCharon@users.noreply.github.com>
---
 pkg/config/root.go      | 25 +++++++++++++++++---
 pkg/config/root_test.go | 51 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 3 deletions(-)
 create mode 100644 pkg/config/root_test.go

diff --git a/pkg/config/root.go b/pkg/config/root.go
index c9df5430..de270312 100644
--- a/pkg/config/root.go
+++ b/pkg/config/root.go
@@ -17,6 +17,7 @@
 package config
 
 import (
+	"os"
 	"os/user"
 	"path/filepath"
 )
@@ -31,17 +32,35 @@ type Root struct {
 }
 
 func NewRoot() (*Root, error) {
-	user, err := user.Current()
+	homeDir, err := userHomeDir()
 	if err != nil {
 		return nil, err
 	}
 
 	return &Root{
-		StorageDir:      filepath.Join(user.HomeDir, ".modctl"),
+		StorageDir:      filepath.Join(homeDir, ".modctl"),
 		Pprof:           false,
 		PprofAddr:       "localhost:6060",
 		DisableProgress: false,
-		LogDir:          filepath.Join(user.HomeDir, ".modctl/logs"),
+		LogDir:          filepath.Join(homeDir, ".modctl/logs"),
 		LogLevel:        "info",
 	}, nil
 }
+
+// userHomeDir returns the home directory of the current user. It prefers
+// os.UserHomeDir, which honors $HOME (%USERPROFILE% on Windows), so that an
+// overridden home directory is respected. os/user.Current queries the user
+// database, which may ignore $HOME, so it is only used as a fallback when the
+// environment variable is not set.
+func userHomeDir() (string, error) {
+	if dir, err := os.UserHomeDir(); err == nil {
+		return dir, nil
+	}
+
+	u, err := user.Current()
+	if err != nil {
+		return "", err
+	}
+
+	return u.HomeDir, nil
+}
diff --git a/pkg/config/root_test.go b/pkg/config/root_test.go
new file mode 100644
index 00000000..e4a4c049
--- /dev/null
+++ b/pkg/config/root_test.go
@@ -0,0 +1,51 @@
+/*
+ *     Copyright 2024 The ModelPack Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package config
+
+import (
+	"os/user"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewRootRespectsHomeEnv(t *testing.T) {
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	// os.UserHomeDir reads USERPROFILE on Windows.
+	t.Setenv("USERPROFILE", home)
+
+	root, err := NewRoot()
+	require.NoError(t, err)
+	assert.Equal(t, filepath.Join(home, ".modctl"), root.StorageDir)
+	assert.Equal(t, filepath.Join(home, ".modctl", "logs"), root.LogDir)
+}
+
+func TestNewRootFallsBackToCurrentUser(t *testing.T) {
+	u, err := user.Current()
+	require.NoError(t, err)
+
+	t.Setenv("HOME", "")
+	t.Setenv("USERPROFILE", "")
+
+	root, err := NewRoot()
+	require.NoError(t, err)
+	assert.Equal(t, filepath.Join(u.HomeDir, ".modctl"), root.StorageDir)
+	assert.Equal(t, filepath.Join(u.HomeDir, ".modctl", "logs"), root.LogDir)
+}