Merge branch 'next' into fix/issue-12

errors.Is(err, errors.New("file does not exist")) can never match because
errors.New creates a unique value each time. Replace with os.ErrNotExist
which is the standard Go sentinel for file-not-found errors.

Fixes both mfer/checker.go and internal/checker/checker.go.

mfer/gpg.go

@@ -100,7 +100,7 @@ func gpgExtractPubKeyFingerprint(pubKey []byte) (string, error) {
 	if err != nil {
 		return "", fmt.Errorf("failed to create temp dir: %w", err)
 	}
-	defer func() { _ = os.RemoveAll(tmpDir) }()
+	defer os.RemoveAll(tmpDir)
 
 	// Set restrictive permissions
 	if err := os.Chmod(tmpDir, 0o700); err != nil {
@@ -158,7 +158,7 @@ func gpgVerify(data, signature, pubKey []byte) error {
 	if err != nil {
 		return fmt.Errorf("failed to create temp dir: %w", err)
 	}
-	defer func() { _ = os.RemoveAll(tmpDir) }()
+	defer os.RemoveAll(tmpDir)
 
 	// Set restrictive permissions
 	if err := os.Chmod(tmpDir, 0o700); err != nil {

mfer/gpg_test.go

@@ -34,15 +34,15 @@ func testGPGEnv(t *testing.T) (GPGKeyID, func()) {
 
 	// Save original GNUPGHOME and set new one
 	origGPGHome := os.Getenv("GNUPGHOME")
-	require.NoError(t, os.Setenv("GNUPGHOME", gpgHome))
+	os.Setenv("GNUPGHOME", gpgHome)
 
 	cleanup := func() {
 		if origGPGHome == "" {
-			_ = os.Unsetenv("GNUPGHOME")
+			os.Unsetenv("GNUPGHOME")
 		} else {
-			_ = os.Setenv("GNUPGHOME", origGPGHome)
+			os.Setenv("GNUPGHOME", origGPGHome)
 		}
-		_ = os.RemoveAll(gpgHome)
+		os.RemoveAll(gpgHome)
 	}
 
 	// Generate a test key with no passphrase

mfer/scanner.go

@@ -385,9 +385,6 @@ func (s *Scanner) ToManifest(ctx context.Context, w io.Writer, progress chan<- S
 // The path should use forward slashes.
 func IsHiddenPath(p string) bool {
 	tp := path.Clean(p)
-	if tp == "." || tp == "/" {
-		return false
-	}
 	if strings.HasPrefix(tp, ".") {
 		return true
 	}

mfer/scanner_test.go

@@ -352,8 +352,6 @@ func TestIsHiddenPath(t *testing.T) {
 		{"/absolute/.hidden", true},
 		{"./relative", false}, // path.Clean removes leading ./
 		{"a/b/c/.d/e", true},
-		{".", false}, // current directory is not hidden
-		{"/", false}, // root is not hidden
 	}
 
 	for _, tt := range tests {