fix: resolve CI failures in docker build

- Install golangci-lint v2 via binary download instead of go install
  (avoids Go 1.25 requirement of golangci-lint v2.10+)
- Add darwin build tags to tests that depend on macOS keychain:
  derivation_index_test.go, pgpunlock_test.go, validation (keychain tests)
- Move generateRandomString to helpers_darwin.go (only called from
  darwin-only keychainunlocker.go)
- Fix unchecked error returns flagged by errcheck linter
- Add gnupg to builder stage for PGP-related tests
- Use --ulimit memlock=-1:-1 in CI for memguard large secret tests
- Add //nolint:unused for intentionally kept but currently unused test helpers

internal/secret/derivation_index_test.go

@@ -1,3 +1,5 @@
+//go:build darwin
+
 package secret
 
 import (

internal/secret/helpers.go

@@ -1,33 +1,11 @@
 package secret
 
 import (
-	"crypto/rand"
 	"fmt"
-	"math/big"
 	"os"
 	"path/filepath"
 )
 
-// generateRandomString generates a random string of the specified length using the given character set
-func generateRandomString(length int, charset string) (string, error) {
-	if length <= 0 {
-		return "", fmt.Errorf("length must be positive")
-	}
-
-	result := make([]byte, length)
-	charsetLen := big.NewInt(int64(len(charset)))
-
-	for i := range length {
-		randomIndex, err := rand.Int(rand.Reader, charsetLen)
-		if err != nil {
-			return "", fmt.Errorf("failed to generate random number: %w", err)
-		}
-		result[i] = charset[randomIndex.Int64()]
-	}
-
-	return string(result), nil
-}
-
 // DetermineStateDir determines the state directory based on environment variables and OS.
 // It returns an error if no usable directory can be determined.
 func DetermineStateDir(customConfigDir string) (string, error) {

internal/secret/helpers_darwin.go

@@ -0,0 +1,29 @@
+//go:build darwin
+
+package secret
+
+import (
+	"crypto/rand"
+	"fmt"
+	"math/big"
+)
+
+// generateRandomString generates a random string of the specified length using the given character set
+func generateRandomString(length int, charset string) (string, error) {
+	if length <= 0 {
+		return "", fmt.Errorf("length must be positive")
+	}
+
+	result := make([]byte, length)
+	charsetLen := big.NewInt(int64(len(charset)))
+
+	for i := range length {
+		randomIndex, err := rand.Int(rand.Reader, charsetLen)
+		if err != nil {
+			return "", fmt.Errorf("failed to generate random number: %w", err)
+		}
+		result[i] = charset[randomIndex.Int64()]
+	}
+
+	return string(result), nil
+}

internal/secret/passphrase_test.go

@@ -24,7 +24,7 @@ func TestPassphraseUnlockerWithRealFS(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Failed to create temp dir: %v", err)
 	}
-	defer os.RemoveAll(tempDir) // Clean up after test
+	defer func() { _ = os.RemoveAll(tempDir) }() // Clean up after test
 
 	// Use the real filesystem
 	fs := afero.NewOsFs()
@@ -155,7 +155,7 @@ func TestPassphraseUnlockerWithRealFS(t *testing.T) {
 	})
 
 	// Unset the environment variable to test interactive prompt
-	os.Unsetenv(secret.EnvUnlockPassphrase)
+	_ = os.Unsetenv(secret.EnvUnlockPassphrase)
 
 	// Test getting identity from prompt (this would require mocking the prompt)
 	// For real integration tests, we'd need to provide a way to mock the passphrase input

internal/secret/pgpunlock_test.go

@@ -1,3 +1,5 @@
+//go:build darwin
+
 package secret_test
 
 import (
@@ -140,7 +142,7 @@ func TestPGPUnlockerWithRealFS(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Failed to create temp dir: %v", err)
 	}
-	defer os.RemoveAll(tempDir) // Clean up after test
+	defer func() { _ = os.RemoveAll(tempDir) }() // Clean up after test
 
 	// Create a temporary GNUPGHOME
 	gnupgHomeDir := filepath.Join(tempDir, "gnupg")

internal/secret/validation_darwin_test.go

@@ -0,0 +1,148 @@
+//go:build darwin
+
+package secret
+
+import (
+	"testing"
+)
+
+func TestValidateKeychainItemName(t *testing.T) {
+	tests := []struct {
+		name     string
+		itemName string
+		wantErr  bool
+	}{
+		// Valid cases
+		{
+			name:     "valid simple name",
+			itemName: "my-secret-key",
+			wantErr:  false,
+		},
+		{
+			name:     "valid name with dots",
+			itemName: "com.example.app.key",
+			wantErr:  false,
+		},
+		{
+			name:     "valid name with underscores",
+			itemName: "my_secret_key_123",
+			wantErr:  false,
+		},
+		{
+			name:     "valid alphanumeric",
+			itemName: "Secret123Key",
+			wantErr:  false,
+		},
+		{
+			name:     "valid with hyphen at start",
+			itemName: "-my-key",
+			wantErr:  false,
+		},
+		{
+			name:     "valid with dot at start",
+			itemName: ".hidden-key",
+			wantErr:  false,
+		},
+
+		// Invalid cases
+		{
+			name:     "empty item name",
+			itemName: "",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with spaces",
+			itemName: "my secret key",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with semicolon",
+			itemName: "key;rm -rf /",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with pipe",
+			itemName: "key|cat /etc/passwd",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with backticks",
+			itemName: "key`whoami`",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with dollar sign",
+			itemName: "key$(whoami)",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with quotes",
+			itemName: "key\"name",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with single quotes",
+			itemName: "key'name",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with backslash",
+			itemName: "key\\name",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with newline",
+			itemName: "key\nname",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with carriage return",
+			itemName: "key\rname",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with ampersand",
+			itemName: "key&echo test",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with redirect",
+			itemName: "key>/tmp/test",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with null byte",
+			itemName: "key\x00name",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with parentheses",
+			itemName: "key(test)",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with brackets",
+			itemName: "key[test]",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with asterisk",
+			itemName: "key*",
+			wantErr:  true,
+		},
+		{
+			name:     "item name with question mark",
+			itemName: "key?",
+			wantErr:  true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateKeychainItemName(tt.itemName)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("validateKeychainItemName() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}

internal/secret/validation_test.go

@@ -155,143 +155,3 @@ func TestValidateGPGKeyID(t *testing.T) {
 	}
 }
 
-func TestValidateKeychainItemName(t *testing.T) {
-	tests := []struct {
-		name     string
-		itemName string
-		wantErr  bool
-	}{
-		// Valid cases
-		{
-			name:     "valid simple name",
-			itemName: "my-secret-key",
-			wantErr:  false,
-		},
-		{
-			name:     "valid name with dots",
-			itemName: "com.example.app.key",
-			wantErr:  false,
-		},
-		{
-			name:     "valid name with underscores",
-			itemName: "my_secret_key_123",
-			wantErr:  false,
-		},
-		{
-			name:     "valid alphanumeric",
-			itemName: "Secret123Key",
-			wantErr:  false,
-		},
-		{
-			name:     "valid with hyphen at start",
-			itemName: "-my-key",
-			wantErr:  false,
-		},
-		{
-			name:     "valid with dot at start",
-			itemName: ".hidden-key",
-			wantErr:  false,
-		},
-
-		// Invalid cases
-		{
-			name:     "empty item name",
-			itemName: "",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with spaces",
-			itemName: "my secret key",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with semicolon",
-			itemName: "key;rm -rf /",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with pipe",
-			itemName: "key|cat /etc/passwd",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with backticks",
-			itemName: "key`whoami`",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with dollar sign",
-			itemName: "key$(whoami)",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with quotes",
-			itemName: "key\"name",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with single quotes",
-			itemName: "key'name",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with backslash",
-			itemName: "key\\name",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with newline",
-			itemName: "key\nname",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with carriage return",
-			itemName: "key\rname",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with ampersand",
-			itemName: "key&echo test",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with redirect",
-			itemName: "key>/tmp/test",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with null byte",
-			itemName: "key\x00name",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with parentheses",
-			itemName: "key(test)",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with brackets",
-			itemName: "key[test]",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with asterisk",
-			itemName: "key*",
-			wantErr:  true,
-		},
-		{
-			name:     "item name with question mark",
-			itemName: "key?",
-			wantErr:  true,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			err := validateKeychainItemName(tt.itemName)
-			if (err != nil) != tt.wantErr {
-				t.Errorf("validateKeychainItemName() error = %v, wantErr %v", err, tt.wantErr)
-			}
-		})
-	}
-}