Function Signature
Description
The Reset() function clears the internal cache, forcing the next call to Dir() to re-detect the home directory. This function generally never has to be called in production code, but is useful in specific scenarios like testing.
When to Use
You should call Reset() when:
- Testing: When you’re modifying the home directory via environment variables (like
HOME, USERPROFILE) in tests and need to re-detect the directory
- Dynamic environments: When the home directory might change during program execution (rare)
- Cache invalidation: After changing environment variables that affect home directory detection
In most production applications, you don’t need to call Reset(). The cache improves performance and the home directory rarely changes during execution.
Parameters
None.
Return Values
None. This function does not return any values.
Behavior
Reset() clears the cached home directory value by:
- Acquiring a write lock on the cache
- Setting the internal cache to an empty string
- Releasing the lock
The next call to Dir() will perform full home directory detection, and the result will be cached again (unless DisableCache is true).
Usage Examples
Testing with Environment Variables
import (
"os"
"testing"
"github.com/mitchellh/go-homedir"
)
func TestHomeDirectory(t *testing.T) {
// Get original home
original, _ := homedir.Dir()
// Change HOME environment variable
os.Setenv("HOME", "/tmp/test-home")
// Clear cache to pick up new value
homedir.Reset()
// Now Dir() will re-detect using new HOME value
newHome, err := homedir.Dir()
if err != nil {
t.Fatal(err)
}
if newHome != "/tmp/test-home" {
t.Errorf("Expected /tmp/test-home, got %s", newHome)
}
// Cleanup: restore original
os.Setenv("HOME", original)
homedir.Reset()
}
Forcing Re-detection
import "github.com/mitchellh/go-homedir"
func main() {
// First call - detects and caches
dir1, _ := homedir.Dir()
fmt.Println("Cached:", dir1)
// Change environment (for some reason)
os.Setenv("HOME", "/new/home")
// Without Reset(), would return cached value
// With Reset(), forces re-detection
homedir.Reset()
dir2, _ := homedir.Dir()
fmt.Println("Re-detected:", dir2)
}
Multiple Test Cases
func TestMultipleHomeScenarios(t *testing.T) {
tests := []struct {
name string
homeVar string
expected string
}{
{"user1", "/home/user1", "/home/user1"},
{"user2", "/home/user2", "/home/user2"},
{"root", "/root", "/root"},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
os.Setenv("HOME", tt.homeVar)
homedir.Reset() // Clear cache for each test
got, err := homedir.Dir()
if err != nil {
t.Fatal(err)
}
if got != tt.expected {
t.Errorf("got %s, want %s", got, tt.expected)
}
})
}
}
Relationship with DisableCache
Reset() and DisableCache serve different purposes:
Reset(): Clears the cache once, forcing the next detection. The result is still cached for subsequent calls.DisableCache = true: Disables caching entirely. Every call to Dir() will re-detect the home directory.
// Using Reset() - cache is cleared once
dir1, _ := homedir.Dir() // Detects and caches
dir2, _ := homedir.Dir() // Uses cache
homedir.Reset() // Clears cache
dir3, _ := homedir.Dir() // Re-detects and caches
dir4, _ := homedir.Dir() // Uses cache again
// Using DisableCache - never caches
homedir.DisableCache = true
dir1, _ := homedir.Dir() // Detects (no cache)
dir2, _ := homedir.Dir() // Detects again (no cache)
dir3, _ := homedir.Dir() // Detects again (no cache)
Thread Safety
Reset() is thread-safe. It uses a mutex lock to ensure safe concurrent access to the cache.
- Dir() - The function whose cache is cleared by
Reset()
- DisableCache - Alternative approach to prevent caching
