Set version to 0.0.2

Order-independent group resolution on top of 0.0.1.

Directory.Build.props

@@ -1,7 +1,7 @@
 <Project>
     <PropertyGroup>
-        <Version>0.0.1.0</Version>
+        <Version>0.0.2.0</Version>
-        <AssemblyVersion>0.0.1.0</AssemblyVersion>
+        <AssemblyVersion>0.0.2.0</AssemblyVersion>
-        <FileVersion>0.0.1.0</FileVersion>
+        <FileVersion>0.0.2.0</FileVersion>
     </PropertyGroup>
 </Project>

Jellyfin.Plugin.WatchedTogether.Tests/DynamicGroupTests.cs

@@ -45,7 +45,8 @@ public class DynamicGroupTests
 
     private sealed record Harness(
         DynamicGroupService Service,
-        Mock<IProvisioningService> Provisioning);
+        Mock<IProvisioningService> Provisioning,
+        StubCryptoProvider Crypto);
 
     private static Harness MakeService(
         IReadOnlyList<User> knownUsers,
@@ -67,6 +68,13 @@ public class DynamicGroupTests
                 return null!;
             });
 
+        // Any known user must also resolve by id, so an existing group can be followed back to its
+        // shared account.
+        foreach (var u in knownUsers)
+        {
+            userManager.Setup(m => m.GetUserById(u.Id)).Returns(u);
+        }
+
         var provisioning = new Mock<IProvisioningService>();
         var createdShared = MakeUser("created-shared");
 
@@ -78,13 +86,15 @@ public class DynamicGroupTests
 
         userManager.Setup(m => m.GetUserById(createdShared.Id)).Returns(createdShared);
 
+        var crypto = new StubCryptoProvider(validPairs);
+
         var service = new DynamicGroupService(
             userManager.Object,
             provisioning.Object,
-            new StubCryptoProvider(validPairs),
+            crypto,
             NullLogger<DynamicGroupService>.Instance);
 
-        return new Harness(service, provisioning);
+        return new Harness(service, provisioning, crypto);
     }
 
     [Fact]
@@ -98,13 +108,108 @@ public class DynamicGroupTests
         var result = await h.Service.TryCreateFromLoginAsync("alice+bob", "alice-pw");
 
         Assert.NotNull(result);
+        // No name is passed: provisioning generates the canonical alphabetical one.
         h.Provisioning.Verify(
             p => p.CreateGroupAsync(
                 It.Is<IReadOnlyList<Guid>>(ids => ids.Count == 2),
-                "alice+bob"),
+                null),
             Times.Once);
     }
 
+    [Fact]
+    public async Task ReversedNameOrder_ReusesTheExistingGroup()
+    {
+        // "john+jane" and "jane+john" are the same group. Jellyfin only calls this code when no
+        // account matches the typed name, so without an order-independent lookup the reversed
+        // spelling would quietly create a second account for the same two people.
+        using var ctx = PluginTestContext.Create();
+        var alice = MakeUser("alice", AliceHash);
+        var bob = MakeUser("bob", BobHash);
+        var shared = MakeUser("alice+bob");
+
+        ctx.Configuration.Groups.Add(new SharedGroup
+        {
+            SharedUserId = shared.Id,
+            MemberUserIds = [alice.Id, bob.Id]
+        });
+
+        var h = MakeService([alice, bob, shared], (BobHash, "bob-pw"));
+
+        var result = await h.Service.TryCreateFromLoginAsync("bob+alice", "bob-pw");
+
+        Assert.NotNull(result);
+        Assert.Equal("alice+bob", result!.SharedUsername);
+        h.Provisioning.VerifyNoOtherCalls();
+    }
+
+    [Fact]
+    public async Task ANewGroup_IsNamedCanonically()
+    {
+        // Provisioning is asked for no particular name so it generates the canonical sorted one,
+        // rather than preserving whatever order happened to be typed.
+        using var ctx = PluginTestContext.Create();
+        var alice = MakeUser("alice", AliceHash);
+        var bob = MakeUser("bob", BobHash);
+        var h = MakeService([alice, bob], (BobHash, "bob-pw"));
+
+        await h.Service.TryCreateFromLoginAsync("bob+alice", "bob-pw");
+
+        h.Provisioning.Verify(
+            p => p.CreateGroupAsync(It.IsAny<IReadOnlyList<Guid>>(), null),
+            Times.Once);
+    }
+
+    [Fact]
+    public async Task ReversedNameOrder_WhenTheGroupIsDisabled_IsRejected()
+    {
+        using var ctx = PluginTestContext.Create();
+        var alice = MakeUser("alice", AliceHash);
+        var bob = MakeUser("bob", BobHash);
+        var shared = MakeUser("alice+bob");
+
+        ctx.Configuration.Groups.Add(new SharedGroup
+        {
+            SharedUserId = shared.Id,
+            MemberUserIds = [alice.Id, bob.Id],
+            IsDisabled = true
+        });
+
+        var h = MakeService([alice, bob, shared], (BobHash, "bob-pw"));
+
+        Assert.Null(await h.Service.TryCreateFromLoginAsync("bob+alice", "bob-pw"));
+        h.Provisioning.VerifyNoOtherCalls();
+    }
+
+    [Fact]
+    public async Task TheFirstTypedMember_HasTheirPasswordCheckedFirst()
+    {
+        // Password verification is a deliberately slow hash comparison, so whoever puts their own
+        // name first should be checked first.
+        using var ctx = PluginTestContext.Create();
+        var alice = MakeUser("alice", AliceHash);
+        var bob = MakeUser("bob", BobHash);
+        var h = MakeService([alice, bob], (BobHash, "bob-pw"));
+
+        await h.Service.TryCreateFromLoginAsync("bob+alice", "bob-pw");
+
+        // Bob was typed first and his password matched, so alice's hash is never touched.
+        Assert.Equal(["B2B2B2B2"], h.Crypto.VerifiedSalts);
+    }
+
+    [Fact]
+    public async Task ALaterMembersPassword_StillWorks()
+    {
+        // The first-typed member is only a preference: the second member's password must still
+        // unlock the group once the first fails to match.
+        using var ctx = PluginTestContext.Create();
+        var alice = MakeUser("alice", AliceHash);
+        var bob = MakeUser("bob", BobHash);
+        var h = MakeService([alice, bob], (BobHash, "bob-pw"));
+
+        Assert.NotNull(await h.Service.TryCreateFromLoginAsync("alice+bob", "bob-pw"));
+        Assert.Equal(["A1A1A1A1", "B2B2B2B2"], h.Crypto.VerifiedSalts);
+    }
+
     [Fact]
     public async Task AnyNamedMembersPassword_Works()
     {

Jellyfin.Plugin.WatchedTogether.Tests/StubCryptoProvider.cs

@@ -21,6 +21,12 @@ public sealed class StubCryptoProvider : ICryptoProvider
         _validPairs = validPairs;
     }
 
+    /// <summary>
+    /// Gets the salt of each credential this provider was asked to verify, in call order. Lets a
+    /// test assert which member's password was checked first.
+    /// </summary>
+    public List<string> VerifiedSalts { get; } = new();
+
     public string DefaultHashMethod => "PBKDF2-SHA512";
 
     public bool Verify(PasswordHash hash, ReadOnlySpan<char> password)
@@ -30,6 +36,7 @@ public sealed class StubCryptoProvider : ICryptoProvider
         // Identify the stored credential by its salt rather than by re-formatting the whole hash,
         // which need not round-trip through Parse/ToString byte for byte.
         var salt = Convert.ToHexString(hash.Salt);
+        VerifiedSalts.Add(salt);
 
         foreach (var (validHash, validPassword) in _validPairs)
         {

Jellyfin.Plugin.WatchedTogether/Services/DynamicGroupService.cs

@@ -116,7 +116,12 @@ public class DynamicGroupService : IDynamicGroupService
 
         // The password must belong to one of the named members. Without this any visitor could
         // conjure a shared account out of two usernames they happened to know.
-        if (!members.Any(m => VerifyPassword(m, password)))
+        //
+        // Members are tried in the order they were typed and the loop stops at the first match, so
+        // whoever types their own name first has their password checked first. Verification is a
+        // deliberately slow hash comparison, so the ordering is worth having.
+        var matched = members.FirstOrDefault(m => VerifyPassword(m, password));
+        if (matched is null)
         {
             _logger.LogWarning(
                 "Dynamic group login for {Username} rejected: no named member's password matched",
@@ -124,11 +129,45 @@ public class DynamicGroupService : IDynamicGroupService
             return null;
         }
 
+        var memberIds = members.Select(m => m.Id).ToList();
+
+        // The same people in a different order are the same group: someone typing "john+jane" must
+        // land on the existing "jane+john" account rather than creating a second one. Jellyfin only
+        // reaches this code when no account matches the typed name, so without this check every
+        // ordering would spawn its own account.
+        var existing = FindGroupWithSameMembers(config, memberIds);
+        if (existing is not null)
+        {
+            if (existing.IsDisabled)
+            {
+                _logger.LogWarning(
+                    "Login for {Username} rejected: the matching group is disabled",
+                    enteredUsername);
+                return null;
+            }
+
+            var existingUser = _userManager.GetUserById(existing.SharedUserId);
+            if (existingUser is null)
+            {
+                _logger.LogWarning(
+                    "Group for {Username} references a shared account that no longer exists",
+                    enteredUsername);
+                return null;
+            }
+
+            _logger.LogInformation(
+                "Login as {Entered} resolved to the existing shared account {Username}",
+                enteredUsername,
+                existingUser.Username);
+
+            return new DynamicGroupResult(existing, existingUser.Username);
+        }
+
+        // Passing no name lets provisioning generate the canonical alphabetically-sorted one, so
+        // the account is named the same whichever order the members were typed in.
         // The account is limited to the libraries all named members share, so creating one at the
         // login screen cannot grant anybody access they did not already have.
-        var group = await _provisioningService.CreateGroupAsync(
+        var group = await _provisioningService.CreateGroupAsync(memberIds, null).ConfigureAwait(false);
-            members.Select(m => m.Id).ToList(),
-            enteredUsername).ConfigureAwait(false);
 
         var sharedUser = _userManager.GetUserById(group.SharedUserId);
         if (sharedUser is null)
@@ -144,6 +183,22 @@ public class DynamicGroupService : IDynamicGroupService
         return new DynamicGroupResult(group, sharedUser.Username);
     }
 
+    /// <summary>
+    /// Finds a configured group whose members are exactly the given set, ignoring order.
+    /// </summary>
+    /// <param name="config">The plugin configuration to search.</param>
+    /// <param name="memberIds">The member identifiers to match.</param>
+    /// <returns>The matching group, or <c>null</c> if no group has that membership.</returns>
+    private static SharedGroup? FindGroupWithSameMembers(
+        PluginConfiguration config,
+        IReadOnlyList<Guid> memberIds)
+    {
+        var wanted = memberIds.ToHashSet();
+
+        return config.Groups.FirstOrDefault(g =>
+            g.MemberUserIds.Count == wanted.Count && wanted.SetEquals(g.MemberUserIds));
+    }
+
     /// <summary>
     /// Verifies a submitted password against a member's live stored hash.
     /// </summary>

Jellyfin.Plugin.WatchedTogether/Services/ProvisioningService.cs

@@ -88,6 +88,12 @@ public class ProvisioningService : IProvisioningService
             members.Add(member);
         }
 
+        // Store members in the same alphabetical order the generated name uses, so that the stored
+        // order is canonical however the members were supplied. Password checks then always run in
+        // a predictable order too.
+        members = members.OrderBy(m => m.Username, StringComparer.OrdinalIgnoreCase).ToList();
+        distinctIds = members.Select(m => m.Id).ToList();
+
         var accountName = string.IsNullOrWhiteSpace(name)
             ? BuildDefaultName(members.Select(m => m.Username), config.NameSeparator)
             : name.Trim();
@@ -165,6 +171,11 @@ public class ProvisioningService : IProvisioningService
             }
         }
 
+        // Keep the stored order canonical, matching how groups are created.
+        distinctIds = distinctIds
+            .OrderBy(id => _userManager.GetUserById(id)?.Username, StringComparer.OrdinalIgnoreCase)
+            .ToList();
+
         group.MemberUserIds = distinctIds;
         group.SyncUnwatched = syncUnwatched;
         group.SyncPlayCount = syncPlayCount;
@@ -211,15 +222,20 @@ public class ProvisioningService : IProvisioningService
 
     /// <summary>
     /// Joins member names into a display name, falling back to a generic name if the result would
-    /// exceed the username column limit. Membership is tracked by GUID, so the name is cosmetic.
+    /// exceed the username column limit.
     /// </summary>
+    /// <remarks>
+    /// Names are sorted alphabetically so that a given set of members always produces the same
+    /// account name. Without this, "jane+john" and "john+jane" would be two different names for the
+    /// same group and would end up as two separate accounts.
+    /// </remarks>
     /// <param name="usernames">The member usernames.</param>
     /// <param name="separator">The configured separator.</param>
     /// <returns>A name that fits within the username length limit.</returns>
     private static string BuildDefaultName(IEnumerable<string> usernames, string separator)
     {
         var sep = string.IsNullOrEmpty(separator) ? "+" : separator;
-        var joined = string.Join(sep, usernames);
+        var joined = string.Join(sep, usernames.OrderBy(n => n, StringComparer.OrdinalIgnoreCase));
 
         if (joined.Length <= MaxUsernameLength)
         {

README.md

@@ -81,13 +81,23 @@ On an unrecognised name, it:
 
 1. Splits the name on the separator (`+` by default) — `alice+bob+carol` → three parts.
 2. Requires **every part** to be an existing, enabled user that is not itself a shared account.
-3. Requires the submitted password to match **one of those members'** stored hashes.
+3. Requires the submitted password to match **one of those members'** stored hashes. Members are
-4. Only then creates the shared account, and returns its name so Jellyfin completes the login.
+   checked in the order you typed them and the check stops at the first match, so putting your own
+   name first is marginally quicker.
+4. Looks for an existing group with exactly those members. If one exists, you are logged into it.
+5. Otherwise creates the shared account, and returns its name so Jellyfin completes the login.
 
 Step 3 is what stops this being an open door: knowing two usernames is not enough to bring an
 account into being. If any check fails, the plugin declines and the login fails exactly as an
 ordinary typo would.
 
+#### Order does not matter
+
+`john+jane` and `jane+john` are the same group. Member names are sorted alphabetically to build the
+account name, and the lookup in step 4 compares members as a set, so both spellings resolve to one
+account rather than creating a second one for the same two people. The account itself is named with
+the sorted spelling — `jane+john` — whichever order you happened to type.
+
 #### The name collision, and why it is harmless
 
 `+` is a legal Jellyfin username character:
@@ -165,7 +175,7 @@ Download the release `.zip`, extract it into a `WatchedTogether` folder inside y
 
 On the shared device, at the Jellyfin login screen:
 
-- **Username:** `alice+bob` (the members' usernames, joined with `+`)
+- **Username:** `alice+bob` (the members' usernames, joined with `+`, in any order)
 - **Password:** your own
 
 That is the whole setup. The account is created on first use and reused from then on. Add a third
@@ -177,7 +187,8 @@ If you would rather provision groups explicitly — or you have turned auto-crea
 
 1. Go to **Dashboard → Plugins → Watched Together**.
 2. Under **Create a group**, select **two or more** members.
-3. Optionally give the account a name. Left blank, the member names are joined with `+`.
+3. Optionally give the account a name. Left blank, the member names are sorted alphabetically and
+   joined with `+`.
 4. Click **Create group**.
 
 Either way, a new user appears in your user list and can be renamed like any other.

build.yaml

@@ -1,7 +1,7 @@
 ---
 name: "Watched Together"
 guid: "aa3288a0-e8c1-43e2-8045-8c3411142a5b"
-version: "0.0.1.0"
+version: "0.0.2.0"
 targetAbi: "10.11.0.0"
 framework: "net9.0"
 overview: "One shared login for several people; watched state flows back to each member's own account"
@@ -26,6 +26,7 @@ dotnet_framework: "net9.0"
 # Point at the plugin project rather than the solution so the test project is not packaged.
 project: "Jellyfin.Plugin.WatchedTogether/Jellyfin.Plugin.WatchedTogether.csproj"
 changelog: >
-  Initial release: shared accounts created on demand at login, multi-password
+  Member order no longer matters when resolving a group: "john+jane" and
-  authentication, one-way played-state sync to members, and library access
+  "jane+john" are the same account instead of creating a second one. Account
-  computed as the intersection of the members'.
+  names are sorted alphabetically, and a member's password is checked in the
+  order the names were typed.

manifest.json

@@ -6,6 +6,15 @@
     "overview": "One shared login for several people; watched state flows back to each member's own account",
     "owner": "dtourolle",
     "category": "General",
-    "versions": []
+    "versions": [
+      {
+        "version": "0.0.1",
+        "changelog": "Release 0.0.1",
+        "targetAbi": "10.11.0.0",
+        "sourceUrl": "https://gitea.tourolle.paris/dtourolle/WatchedTogether/releases/download/v0.0.1/watched-together_0.0.1.0.zip",
+        "checksum": "f703f027db22c0bc348b1cb0cee6bb08",
+        "timestamp": "2026-07-29T22:17:28Z"
+      }
+    ]
   }
 ]