Allow only valid characters when creating collections.

Penumbra/Collections/CollectionManager.cs

@@ -79,7 +79,7 @@ public partial class ModCollection
         // and no existing collection results in the same filename as name.
         public bool CanAddCollection( string name, out string fixedName )
         {
-            if( name.Length == 0 )
+            if( !IsValidName( name ) )
             {
                 fixedName = string.Empty;
                 return false;
@@ -156,7 +156,7 @@ public partial class ModCollection
             var collection = _collections[ idx ];
 
             // Clear own inheritances.
-            foreach(var inheritance in collection.Inheritance)
+            foreach( var inheritance in collection.Inheritance )
             {
                 collection.ClearSubscriptions( inheritance );
             }

Penumbra/Collections/ModCollection.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using OtterGui.Filesystem;
 using Penumbra.Mods;
 
 namespace Penumbra.Collections;
@@ -25,7 +26,7 @@ public partial class ModCollection
 
     // Get the first two letters of a collection name and its Index (or None if it is the empty collection).
     public string AnonymizedName
-        => this == Empty ? Empty.Name : Name.Length > 2 ? $"{Name[..2]}... ({Index})" : $"{Name} ({Index})";
+        => this == Empty ? Empty.Name : Name.Length > 2 ? $"{Name[ ..2 ]}... ({Index})" : $"{Name} ({Index})";
 
     public int Version { get; private set; }
     public int Index { get; private set; } = -1;
@@ -94,6 +95,11 @@ public partial class ModCollection
     public ModCollection Duplicate( string name )
         => new(name, this);
 
+    // Check if a name is valid to use for a collection.
+    // Does not check for uniqueness.
+    public static bool IsValidName( string name )
+        => name.Length > 0 && name.All( c => !c.IsInvalidAscii() && c is not '|' && !c.IsInvalidInPath()  );
+
     // Remove all settings for not currently-installed mods.
     public void CleanUnavailableSettings()
     {

Penumbra/UI/ConfigWindow.CollectionsTab.cs

@@ -85,7 +85,7 @@ public partial class ConfigWindow
               + "You can use multiple collections to quickly switch between sets of mods." );
 
             // Creation buttons.
-            var tt = _canAddCollection ? string.Empty : "Please enter a unique name before creating a collection.";
+            var tt = _canAddCollection ? string.Empty : "Please enter a unique name only consisting of symbols valid in a path but no '|' before creating a collection.";
             if( ImGuiUtil.DrawDisabledButton( "Create New Empty Collection", Vector2.Zero, tt, !_canAddCollection ) )
             {
                 CreateNewCollection( false );