refactor: remove dead code and optimize slice allocation in transit module (#101)

- Remove unused `List` repository methods from PostgreSQL and MySQL transit key repositories.
- Optimize `encryptedData` slice allocation in `Encrypt` use case method to pre-allocate exact capacity.
- This aligns with the "improve-transit" effort to reduce maintenance surface and improve performance.

Author: allisson

internal/transit/repository/mysql/mysql_transit_key_repository.go

@@ -155,74 +155,6 @@ func (m *MySQLTransitKeyRepository) GetByNameAndVersion(
 	return &transitKey, nil
 }
 
-// List retrieves transit keys ordered by name ascending with pagination.
-// Returns the latest version for each key.
-func (m *MySQLTransitKeyRepository) List(
-	ctx context.Context,
-	offset, limit int,
-) ([]*transitDomain.TransitKey, error) {
-	querier := database.GetTx(ctx, m.db)
-
-	query := `
-		SELECT tk.id, tk.name, tk.version, tk.dek_id, tk.created_at, tk.deleted_at
-		FROM transit_keys tk
-		INNER JOIN (
-			SELECT name, MAX(version) as max_version
-			FROM transit_keys
-			WHERE deleted_at IS NULL
-			GROUP BY name
-			ORDER BY name ASC
-			LIMIT ? OFFSET ?
-		) latest ON tk.name = latest.name AND tk.version = latest.max_version
-		ORDER BY tk.name ASC`
-
-	rows, err := querier.QueryContext(ctx, query, limit, offset)
-	if err != nil {
-		return nil, apperrors.Wrap(err, "failed to list transit keys")
-	}
-	defer func() {
-		_ = rows.Close()
-	}()
-
-	var transitKeys []*transitDomain.TransitKey
-	for rows.Next() {
-		var transitKey transitDomain.TransitKey
-		var id, dekID []byte
-
-		err := rows.Scan(
-			&id,
-			&transitKey.Name,
-			&transitKey.Version,
-			&dekID,
-			&transitKey.CreatedAt,
-			&transitKey.DeletedAt,
-		)
-		if err != nil {
-			return nil, apperrors.Wrap(err, "failed to scan transit key")
-		}
-
-		if err := transitKey.ID.UnmarshalBinary(id); err != nil {
-			return nil, apperrors.Wrap(err, "failed to unmarshal transit key id")
-		}
-
-		if err := transitKey.DekID.UnmarshalBinary(dekID); err != nil {
-			return nil, apperrors.Wrap(err, "failed to unmarshal dek id")
-		}
-
-		transitKeys = append(transitKeys, &transitKey)
-	}
-
-	if err := rows.Err(); err != nil {
-		return nil, apperrors.Wrap(err, "error iterating transit keys")
-	}
-
-	if transitKeys == nil {
-		transitKeys = make([]*transitDomain.TransitKey, 0)
-	}
-
-	return transitKeys, nil
-}
-
 // ListCursor retrieves transit keys ordered by name ascending using cursor-based pagination.
 // Returns the latest version for each key.
 func (m *MySQLTransitKeyRepository) ListCursor(

internal/transit/repository/postgresql/postgresql_transit_key_repository.go

@@ -123,63 +123,6 @@ func (p *PostgreSQLTransitKeyRepository) GetByNameAndVersion(
 	return &transitKey, nil
 }
 
-// List retrieves transit keys ordered by name ascending with pagination.
-// Returns the latest version for each key.
-func (p *PostgreSQLTransitKeyRepository) List(
-	ctx context.Context,
-	offset, limit int,
-) ([]*transitDomain.TransitKey, error) {
-	querier := database.GetTx(ctx, p.db)
-
-	query := `
-		SELECT tk.id, tk.name, tk.version, tk.dek_id, tk.created_at, tk.deleted_at
-		FROM transit_keys tk
-		INNER JOIN (
-			SELECT name, MAX(version) as max_version
-			FROM transit_keys
-			WHERE deleted_at IS NULL
-			GROUP BY name
-			ORDER BY name ASC
-			LIMIT $1 OFFSET $2
-		) latest ON tk.name = latest.name AND tk.version = latest.max_version
-		ORDER BY tk.name ASC`
-
-	rows, err := querier.QueryContext(ctx, query, limit, offset)
-	if err != nil {
-		return nil, apperrors.Wrap(err, "failed to list transit keys")
-	}
-	defer func() {
-		_ = rows.Close()
-	}()
-
-	var transitKeys []*transitDomain.TransitKey
-	for rows.Next() {
-		var transitKey transitDomain.TransitKey
-		err := rows.Scan(
-			&transitKey.ID,
-			&transitKey.Name,
-			&transitKey.Version,
-			&transitKey.DekID,
-			&transitKey.CreatedAt,
-			&transitKey.DeletedAt,
-		)
-		if err != nil {
-			return nil, apperrors.Wrap(err, "failed to scan transit key")
-		}
-		transitKeys = append(transitKeys, &transitKey)
-	}
-
-	if err := rows.Err(); err != nil {
-		return nil, apperrors.Wrap(err, "error iterating transit keys")
-	}
-
-	if transitKeys == nil {
-		transitKeys = make([]*transitDomain.TransitKey, 0)
-	}
-
-	return transitKeys, nil
-}
-
 // ListCursor retrieves transit keys ordered by name ascending using cursor-based pagination.
 // Returns the latest version for each key.
 func (p *PostgreSQLTransitKeyRepository) ListCursor(

internal/transit/usecase/transit_key_usecase.go

@@ -201,8 +201,9 @@ func (t *transitKeyUseCase) Encrypt(
 
 	// Combine ciphertext and nonce (nonce is prepended to ciphertext by AEAD)
 	// The AEAD Encrypt returns ciphertext with authentication tag, we need to store nonce separately
-	//nolint:gocritic // intentionally creating new slice with combined nonce and ciphertext
-	encryptedData := append(nonce, ciphertext...)
+	encryptedData := make([]byte, 0, len(nonce)+len(ciphertext))
+	encryptedData = append(encryptedData, nonce...)
+	encryptedData = append(encryptedData, ciphertext...)
 
 	return &transitDomain.EncryptedBlob{
 		Version:    transitKey.Version,