Support atomic organization role sets and owner-managed invitations

Signed-off-by: Cole Speelman <crspeelman@gmail.com>

organizations/role_invitations.go

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: MPL-2.0
+
+package organizations
+
+import (
+	"context"
+	"errors"
+	"slices"
+	"time"
+)
+
+var ErrRoleInvitationUnsupported = errors.New("organizations: atomic role-set invitations are unsupported")
+
+// RoleInvitationRepository must preserve the entire role set and its required
+// owner authority, then commit acceptance, membership, grants and audit together.
+type RoleInvitationRepository interface {
+	CreateInvitationWithRoles(context.Context, Invitation, string, AuditEvent) error
+	AcceptInvitationWithRoles(context.Context, [32]byte, string, string, time.Time, AuditEvent) error
+}
+
+// RoleNames returns a validated copy of the invitation's direct roles. The older
+// DirectRole remains supported; supplying both forms is an error, not a union.
+func (invitation Invitation) RoleNames() ([]string, error) {
+	if invitation.DirectRole != "" && len(invitation.DirectRoles) > 0 || len(invitation.DirectRoles) > 16 {
+		return nil, errors.New("organizations: invalid invitation roles")
+	}
+	roles := append([]string(nil), invitation.DirectRoles...)
+	if invitation.DirectRole != "" {
+		roles = append(roles, invitation.DirectRole)
+	}
+	slices.Sort(roles)
+	for i, role := range roles {
+		if !safeNamePattern.MatchString(role) || i > 0 && role == roles[i-1] {
+			return nil, errors.New("organizations: invalid invitation role")
+		}
+	}
+	return roles, nil
+}