Add loop protection

geneit_backend/src/controllers/members_controller.rs

@@ -262,6 +262,20 @@ pub async fn update(m: FamilyAndMemberInPath, req: web::Json<MemberRequest>) ->
         return Ok(HttpResponse::BadRequest().body(e.to_string()));
     }
 
+    // Check for potential loops
+    let members = members_service::get_all_of_family(member.family_id()).await?;
+    let mut members_ref = Vec::with_capacity(members.len());
+    members_ref.push(&member);
+    for m in &members {
+        if m.id() != member.id() {
+            members_ref.push(m);
+        }
+    }
+    if members_service::loop_detection::detect_loop(&members_ref) {
+        log::warn!("Membership update rejected due to detected loop!");
+        return Ok(HttpResponse::NotAcceptable().json("Loop detected!"));
+    }
+
     members_service::update(&mut member).await?;
 
     Ok(HttpResponse::Accepted().finish())