fix: resolve golangci-lint errcheck and cross-platform test failures

- Add explicit error ignoring for fmt.Fprintf and resp.Body.Close
- Clear CI env vars in tests so ShouldCheck doesn't short-circuit on
  GitHub Actions runners
- Set USERPROFILE alongside HOME for Windows test compatibility
- Use unambiguously invalid YAML for corrupt state file test

Author: debidong

internal/cli/update.go

@@ -17,29 +17,30 @@ func newUpdateCmd() *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "update",
 		Short: "Update flashduty to the latest version",
-		RunE: func(cmd *cobra.Command, args []string) error {
-			fmt.Fprintf(cmd.OutOrStdout(), "Current version: %s\n", versionStr)
-			fmt.Fprintf(cmd.OutOrStdout(), "Checking for updates...\n")
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			w := cmd.OutOrStdout()
+			_, _ = fmt.Fprintf(w, "Current version: %s\n", versionStr)
+			_, _ = fmt.Fprintf(w, "Checking for updates...\n")
 
 			result, err := update.CheckForUpdate(versionStr)
 			if err != nil {
 				return fmt.Errorf("failed to check for updates: %w", err)
 			}
 
 			if !result.UpdateAvailable {
-				fmt.Fprintf(cmd.OutOrStdout(), "Already up to date (%s).\n", versionStr)
+				_, _ = fmt.Fprintf(w, "Already up to date (%s).\n", versionStr)
 				return nil
 			}
 
-			fmt.Fprintf(cmd.OutOrStdout(), "A new version is available: v%s -> %s\n",
+			_, _ = fmt.Fprintf(w, "A new version is available: v%s -> %s\n",
 				update.StripV(versionStr), result.LatestVersion)
-			fmt.Fprintf(cmd.OutOrStdout(), "Release: %s\n", result.LatestURL)
+			_, _ = fmt.Fprintf(w, "Release: %s\n", result.LatestURL)
 
 			if flagCheck {
 				return nil
 			}
 
-			fmt.Fprintf(cmd.OutOrStdout(), "\nUpdating...\n")
+			_, _ = fmt.Fprintf(w, "\nUpdating...\n")
 			return runInstaller(cmd)
 		},
 	}
@@ -66,6 +67,6 @@ func runInstaller(cmd *cobra.Command) error {
 		return fmt.Errorf("update failed: %w", err)
 	}
 
-	fmt.Fprintf(cmd.OutOrStdout(), "\nUpdate complete. Run 'flashduty version' to verify.\n")
+	_, _ = fmt.Fprintf(cmd.OutOrStdout(), "\nUpdate complete. Run 'flashduty version' to verify.\n")
 	return nil
 }

internal/update/check.go

@@ -105,7 +105,7 @@ func fetchLatestVersion() (string, string, error) {
 	if err != nil {
 		return "", "", fmt.Errorf("failed to fetch latest release: %w", err)
 	}
-	defer resp.Body.Close()
+	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
 		return "", "", fmt.Errorf("GitHub API returned %d", resp.StatusCode)

internal/update/check_test.go

@@ -6,12 +6,32 @@ import (
 	"net/http/httptest"
 	"os"
 	"path/filepath"
+	"runtime"
 	"testing"
 	"time"
 
 	"gopkg.in/yaml.v3"
 )
 
+// setTestHome overrides the home directory for testing across all platforms.
+func setTestHome(t *testing.T, dir string) {
+	t.Helper()
+	t.Setenv("HOME", dir)
+	if runtime.GOOS == "windows" {
+		t.Setenv("USERPROFILE", dir)
+	}
+}
+
+// clearCIEnv clears CI-related env vars so ShouldCheck doesn't short-circuit.
+func clearCIEnv(t *testing.T) {
+	t.Helper()
+	t.Setenv("CI", "")
+	t.Setenv("GITHUB_ACTIONS", "")
+	t.Setenv("JENKINS_URL", "")
+	t.Setenv("GITLAB_CI", "")
+	t.Setenv("FLASHDUTY_NO_UPDATE_CHECK", "")
+}
+
 func TestStripV(t *testing.T) {
 	tests := []struct {
 		in, want string
@@ -101,7 +121,8 @@ func TestShouldCheck_CI(t *testing.T) {
 
 func TestShouldCheck_RecentCheck(t *testing.T) {
 	tmp := t.TempDir()
-	t.Setenv("HOME", tmp)
+	setTestHome(t, tmp)
+	clearCIEnv(t)
 
 	dir := filepath.Join(tmp, ".flashduty")
 	if err := os.MkdirAll(dir, 0700); err != nil {
@@ -124,7 +145,8 @@ func TestShouldCheck_RecentCheck(t *testing.T) {
 
 func TestShouldCheck_StaleCheck(t *testing.T) {
 	tmp := t.TempDir()
-	t.Setenv("HOME", tmp)
+	setTestHome(t, tmp)
+	clearCIEnv(t)
 
 	dir := filepath.Join(tmp, ".flashduty")
 	if err := os.MkdirAll(dir, 0700); err != nil {
@@ -147,7 +169,7 @@ func TestShouldCheck_StaleCheck(t *testing.T) {
 
 func TestLoadSaveState(t *testing.T) {
 	tmp := t.TempDir()
-	t.Setenv("HOME", tmp)
+	setTestHome(t, tmp)
 
 	now := time.Now().Truncate(time.Second)
 	want := &State{
@@ -174,13 +196,13 @@ func TestLoadSaveState(t *testing.T) {
 
 func TestLoadState_CorruptFile(t *testing.T) {
 	tmp := t.TempDir()
-	t.Setenv("HOME", tmp)
+	setTestHome(t, tmp)
 
 	dir := filepath.Join(tmp, ".flashduty")
 	if err := os.MkdirAll(dir, 0700); err != nil {
 		t.Fatal(err)
 	}
-	if err := os.WriteFile(filepath.Join(dir, stateFileName), []byte(":::invalid yaml"), 0600); err != nil {
+	if err := os.WriteFile(filepath.Join(dir, stateFileName), []byte("{[invalid yaml"), 0600); err != nil {
 		t.Fatal(err)
 	}
 
@@ -252,7 +274,7 @@ func TestFetchLatestVersion_InvalidJSON(t *testing.T) {
 
 func TestCheckForUpdate(t *testing.T) {
 	tmp := t.TempDir()
-	t.Setenv("HOME", tmp)
+	setTestHome(t, tmp)
 
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		rel := githubRelease{