make Ancestors exclude self

csharp/App/Backend/DataTypes/Methods/Folder.cs

@@ -33,7 +33,9 @@ public static class FolderMethods
 
     public static IEnumerable<Folder> Ancestors(this Folder folder)
     {
-        return folder.Unfold(Parent);
+        return folder
+              .Unfold(Parent)
+              .Skip(1);  // skip self
     }
 
     public static Folder? Parent(this Folder folder)

csharp/App/Backend/DataTypes/Methods/Installation.cs

@@ -9,9 +9,12 @@ public static class InstallationMethods
     {
         var parentFolder = Parent(installation);
 
-        return parentFolder is null 
+        if (parentFolder is null)
-             ? Enumerable.Empty<Folder>() 
+            return Enumerable.Empty<Folder>();
-             : parentFolder.Ancestors();
+        
+        return parentFolder
+              .Ancestors()
+              .Prepend(parentFolder);
     }
     
     public static Folder? Parent(this Installation installation)

csharp/App/Backend/DataTypes/Methods/User.cs

@@ -1,8 +1,5 @@
-using System.Net.Http.Headers;
 using System.Net.Mail;
 using System.Security.Cryptography;
-using System.Text.Json.Nodes;
-using System.Text.RegularExpressions;
 using InnovEnergy.App.Backend.Database;
 using InnovEnergy.Lib.Utils;
 using Convert = System.Convert;
@@ -88,7 +85,9 @@ public static class UserMethods
 
     private static IEnumerable<User> Ancestors(this User user)
     {
-        return user.Unfold(Parent);
+        return user
+              .Unfold(Parent)
+              .Skip(1);  // skip self
     }
 
     public static Boolean VerifyPassword(this User user, String password)
@@ -135,7 +134,8 @@ public static class UserMethods
         if (folder is null)
             return false;
         
-        return folder
+        return user.HasDirectAccessTo(folder)
+            || folder
               .Ancestors()
               .Any(user.HasDirectAccessTo);
     }
@@ -144,7 +144,7 @@ public static class UserMethods
     {
         return Db
               .User2Installation
-              .Any(r => r.InstallationId == installation.Id && r.UserId == user.Id);
+              .Any(r => r.UserId == user.Id && r.InstallationId == installation.Id);
     }
 
     public static Boolean HasAccessTo(this User user, Installation? installation)
@@ -163,7 +163,6 @@ public static class UserMethods
         
         return other
               .Ancestors()
-              .Skip(1) // Important! skip self, user cannot delete or edit himself
               .Contains(user);
     }