add limits to switch members and proxy tag length

PluralKit.Bot/Commands/MemberProxy.cs

@@ -78,6 +78,8 @@ namespace PluralKit.Bot
                 if (tagToAdd.IsEmpty) throw Errors.EmptyProxyTags(target);
                 if (target.ProxyTags.Contains(tagToAdd))
                     throw Errors.ProxyTagAlreadyExists(tagToAdd, target);
+                if (tagToAdd.ProxyString.Length > Limits.MaxProxyTagLength)
+                    throw new PKError($"Proxy tag too long ({tagToAdd.ProxyString.Length} > {Limits.MaxProxyTagLength} characters).");
                 
                 if (!await WarnOnConflict(tagToAdd))
                     throw Errors.GenericCancelled();

PluralKit.Bot/Commands/Switch.cs

@@ -40,6 +40,8 @@ namespace PluralKit.Bot
             // Make sure there are no dupes in the list
             // We do this by checking if removing duplicate member IDs results in a list of different length 
             if (members.Select(m => m.Id).Distinct().Count() != members.Count) throw Errors.DuplicateSwitchMembers;
+            if (members.Count > Limits.MaxSwitchMemberCount)
+                throw new PKError($"Switch contains too many members ({members.Count} > {Limits.MaxSwitchMemberCount} members).");
 
             // Find the last switch and its members if applicable
             await using var conn = await _db.Obtain();