fix(db): restore the PostgreSQL upgrade path

The v12.0 rebase replaced the PostgreSQL provider's initial migration instead of
adding to it, so an existing database kept the pre-12.0 schema while the code
migrations ran against it and startup aborted on a missing NormalizedUsername.

- restore 20260305010333_InitialPostgreSql as the baseline
- add 20260306000000_UpgradeToServer12Schema carrying it to the 12.0 model
- convert OwnerId and PrimaryVersionId to uuid with explicit casts, clear
  unparseable ids and repoint dangling owners at the placeholder item
- drop orphaned permissions and preferences before UserId becomes non-nullable
- add 20260524120336_AddUniqueNormalizedUsernameIndex after the code migration
  that fills the column in
- read an empty or unknown encoding.xml EncoderPreset as the default
- cover both paths against a real PostgreSQL and guard the migration ordering

tests/Jellyfin.Model.Tests/Configuration/EncodingOptionsTests.cs

@@ -0,0 +1,50 @@
+using System.IO;
+using System.Xml.Serialization;
+using MediaBrowser.Model.Configuration;
+using MediaBrowser.Model.Entities;
+using Xunit;
+
+namespace Jellyfin.Model.Tests.Configuration;
+
+public class EncodingOptionsTests
+{
+    [Theory]
+    [InlineData("<EncoderPreset></EncoderPreset>")]
+    [InlineData("<EncoderPreset />")]
+    [InlineData("<EncoderPreset>  </EncoderPreset>")]
+    [InlineData("<EncoderPreset>notapreset</EncoderPreset>")]
+    public void Deserialize_UnreadableEncoderPreset_FallsBackToDefault(string encoderPresetElement)
+    {
+        var options = Deserialize($"<EncodingOptions>{encoderPresetElement}<H264Crf>21</H264Crf></EncodingOptions>");
+
+        Assert.Equal(EncoderPreset.auto, options.EncoderPreset);
+
+        // The rest of the file has to survive: a throwing preset used to discard every other encoding setting.
+        Assert.Equal(21, options.H264Crf);
+    }
+
+    [Fact]
+    public void Deserialize_KnownEncoderPreset_IsKept()
+    {
+        var options = Deserialize("<EncodingOptions><EncoderPreset>veryfast</EncoderPreset></EncodingOptions>");
+
+        Assert.Equal(EncoderPreset.veryfast, options.EncoderPreset);
+    }
+
+    [Fact]
+    public void Serialize_WritesTheEncoderPresetElement()
+    {
+        var serializer = new XmlSerializer(typeof(EncodingOptions));
+        using var writer = new StringWriter();
+        serializer.Serialize(writer, new EncodingOptions { EncoderPreset = EncoderPreset.slow });
+
+        Assert.Contains("<EncoderPreset>slow</EncoderPreset>", writer.ToString(), System.StringComparison.Ordinal);
+    }
+
+    private static EncodingOptions Deserialize(string xml)
+    {
+        var serializer = new XmlSerializer(typeof(EncodingOptions));
+        using var reader = new StringReader(xml);
+        return (EncodingOptions)serializer.Deserialize(reader)!;
+    }
+}

tests/Jellyfin.Server.Tests/Jellyfin.Server.Tests.csproj

@@ -10,6 +10,8 @@
     <PackageReference Include="AutoFixture.Xunit3" />
     <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" />
+    <PackageReference Include="Npgsql" />
+    <PackageReference Include="Testcontainers.PostgreSql" />
     <PackageReference Include="xunit.v3" />
     <PackageReference Include="xunit.runner.visualstudio">
       <PrivateAssets>all</PrivateAssets>

tests/Jellyfin.Server.Tests/Migrations/PostgreSqlMigrationOrderingTests.cs

@@ -0,0 +1,80 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using Jellyfin.Database.Implementations;
+using Jellyfin.Database.Implementations.DbConfiguration;
+using Jellyfin.Database.Implementations.Locking;
+using Jellyfin.Database.Providers.PostgreSQL;
+using Jellyfin.Server.Migrations;
+using Jellyfin.Server.Migrations.Stages;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.Extensions.Logging.Abstractions;
+using Npgsql;
+using Xunit;
+
+namespace Jellyfin.Server.Tests.Migrations;
+
+/// <summary>
+/// Schema migrations and the code migrations of the CoreInitialisation stage are sorted into one list by id, so the
+/// ids the PostgreSQL provider ships decide which schema those code migrations see.
+/// </summary>
+public class PostgreSqlMigrationOrderingTests
+{
+    private const string UsernameCodeMigrationId = "20260522092304_UpdateNormalizedUsername";
+    private const string UsernameIndexMigrationId = "20260524120336_AddUniqueNormalizedUsernameIndex";
+
+    [Fact]
+    public void SchemaMigrations_AreOrderedBeforeTheCodeMigrationsThatNeedThem()
+    {
+        var schemaMigrationIds = PostgreSqlMigrationIds().Where(id => !string.Equals(id, UsernameIndexMigrationId, StringComparison.Ordinal));
+
+        foreach (var codeMigrationId in CoreInitialisationCodeMigrationIds())
+        {
+            foreach (var schemaMigrationId in schemaMigrationIds)
+            {
+                Assert.True(
+                    string.CompareOrdinal(schemaMigrationId, codeMigrationId) < 0,
+                    $"Schema migration {schemaMigrationId} has to be ordered before code migration {codeMigrationId}, "
+                    + "otherwise the code migration runs against a schema that predates it.");
+            }
+        }
+    }
+
+    [Fact]
+    public void UniqueUsernameIndex_IsOrderedAfterTheUsernameCodeMigration()
+    {
+        Assert.Contains(UsernameIndexMigrationId, PostgreSqlMigrationIds());
+        Assert.Contains(UsernameCodeMigrationId, CoreInitialisationCodeMigrationIds());
+        Assert.True(
+            string.CompareOrdinal(UsernameIndexMigrationId, UsernameCodeMigrationId) > 0,
+            "The unique index can only be created once the code migration has filled in the normalized usernames.");
+    }
+
+    private static IReadOnlyList<string> PostgreSqlMigrationIds()
+    {
+        const string DummyConnectionString = "Host=localhost;Database=jellyfin;Username=postgres;Password=postgres";
+        using var dataSource = new NpgsqlDataSourceBuilder(DummyConnectionString).Build();
+        var optionsBuilder = new DbContextOptionsBuilder<JellyfinDbContext>();
+        var provider = new PostgreSqlDatabaseProvider(dataSource);
+        provider.Initialise(optionsBuilder, new DatabaseConfigurationOptions { DatabaseType = "PostgreSQL" });
+        using var context = new JellyfinDbContext(
+            optionsBuilder.Options,
+            NullLogger<JellyfinDbContext>.Instance,
+            provider,
+            new NoLockBehavior(NullLogger<NoLockBehavior>.Instance));
+
+        return [.. context.GetService<IMigrationsAssembly>().Migrations.Keys.OrderBy(id => id, StringComparer.Ordinal)];
+    }
+
+    private static IReadOnlyList<string> CoreInitialisationCodeMigrationIds()
+    {
+        return [.. typeof(JellyfinMigrationAttribute).Assembly.GetTypes()
+            .Select(type => (Type: type, Metadata: type.GetCustomAttribute<JellyfinMigrationAttribute>()))
+            .Where(candidate => candidate.Metadata?.Stage == JellyfinMigrationStageTypes.CoreInitialisation)
+            .Select(candidate => new CodeMigration(candidate.Type, candidate.Metadata!, null).BuildCodeMigrationId())
+            .OrderBy(id => id, StringComparer.Ordinal)];
+    }
+}

tests/Jellyfin.Server.Tests/Migrations/PostgreSqlUpgradeTests.cs

@@ -0,0 +1,429 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Threading;
+using System.Threading.Tasks;
+using DotNet.Testcontainers.Builders;
+using Jellyfin.Database.Implementations;
+using Jellyfin.Database.Implementations.DbConfiguration;
+using Jellyfin.Database.Implementations.Entities;
+using Jellyfin.Database.Implementations.Locking;
+using Jellyfin.Database.Providers.PostgreSQL;
+using Jellyfin.Server.Migrations.Routines;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.Extensions.Logging.Abstractions;
+using Npgsql;
+using Testcontainers.PostgreSql;
+using Xunit;
+
+namespace Jellyfin.Server.Tests.Migrations;
+
+/// <summary>
+/// Verifies that a PostgreSQL database created by an earlier build reaches the current schema, and that a fresh
+/// install ends up with exactly the same schema.
+/// </summary>
+[Trait("Category", "RequiresDocker")]
+public sealed class PostgreSqlUpgradeTests : IAsyncLifetime
+{
+    private const string BaselineMigrationId = "20260305010333_InitialPostgreSql";
+    private const string SchemaUpgradeMigrationId = "20260306000000_UpgradeToServer12Schema";
+    private const string UsernameIndexMigrationId = "20260524120336_AddUniqueNormalizedUsernameIndex";
+
+    private const string PlaceholderItemId = "00000000-0000-0000-0000-000000000001";
+    private const string OwnerItemId = "11111111-1111-1111-1111-111111111111";
+    private const string OwnedItemId = "22222222-2222-2222-2222-222222222222";
+    private const string UnparseableOwnerItemId = "33333333-3333-3333-3333-333333333333";
+    private const string DanglingOwnerItemId = "44444444-4444-4444-4444-444444444444";
+    private const string AliceId = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa";
+    private const string BobId = "bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb";
+
+    private readonly PostgreSqlContainer _container;
+
+    public PostgreSqlUpgradeTests()
+    {
+        _container = new PostgreSqlBuilder("postgres:16-alpine")
+            .WithWaitStrategy(Wait.ForUnixContainer().UntilCommandIsCompleted("pg_isready"))
+            .Build();
+    }
+
+    public async ValueTask InitializeAsync()
+    {
+        await _container.StartAsync().ConfigureAwait(false);
+
+        // pg_isready also answers for the short-lived server the entrypoint runs while initializing the data
+        // directory, so wait until a real connection is accepted before handing the container to a test.
+        await using var dataSource = new NpgsqlDataSourceBuilder(_container.GetConnectionString()).Build();
+        for (var attempt = 1; ; attempt++)
+        {
+            try
+            {
+                await ExecuteAsync(dataSource, "SELECT 1", CancellationToken.None).ConfigureAwait(false);
+                return;
+            }
+            catch (NpgsqlException) when (attempt < 30)
+            {
+                await Task.Delay(TimeSpan.FromSeconds(1)).ConfigureAwait(false);
+            }
+        }
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        await _container.DisposeAsync().ConfigureAwait(false);
+    }
+
+    [Fact]
+    public async Task FreshInstall_AppliesTheWholeChain()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var connectionString = await CreateDatabaseAsync("fresh_install", cancellationToken);
+
+        await using var dataSource = new NpgsqlDataSourceBuilder(connectionString).Build();
+        await MigrateAsync(dataSource, null, cancellationToken);
+
+        Assert.Equal(
+            new[] { BaselineMigrationId, SchemaUpgradeMigrationId, UsernameIndexMigrationId },
+            await AppliedMigrationsAsync(dataSource, cancellationToken));
+        await AssertServer12SchemaAsync(dataSource, cancellationToken);
+    }
+
+    [Fact]
+    public async Task LegacyDatabase_UpgradesToServer12Schema()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var connectionString = await CreateDatabaseAsync("legacy_upgrade", cancellationToken);
+
+        await using var dataSource = new NpgsqlDataSourceBuilder(connectionString).Build();
+        await CreateLegacyDatabaseAsync(dataSource, cancellationToken);
+
+        // The database knows only the migration the previous build shipped, and the two that carry it forward are the
+        // ones the startup sequence has to pick up.
+        Assert.Equal(new[] { BaselineMigrationId }, await AppliedMigrationsAsync(dataSource, cancellationToken));
+        Assert.Equal(
+            new[] { SchemaUpgradeMigrationId, UsernameIndexMigrationId },
+            await PendingMigrationsAsync(dataSource, cancellationToken));
+
+        await RunUpgradeInStartupOrderAsync(dataSource, cancellationToken);
+
+        Assert.Empty(await PendingMigrationsAsync(dataSource, cancellationToken));
+        await AssertServer12SchemaAsync(dataSource, cancellationToken);
+
+        // The code migration that the startup sequence runs between the two schema migrations has to have filled the
+        // new column in, otherwise the unique index could not have been created.
+        Assert.Equal("ALICE", await ScalarAsync<string>(dataSource, $"""SELECT "NormalizedUsername" FROM "Users" WHERE "Id" = '{AliceId}'""", cancellationToken));
+        Assert.Equal("BOB", await ScalarAsync<string>(dataSource, $"""SELECT "NormalizedUsername" FROM "Users" WHERE "Id" = '{BobId}'""", cancellationToken));
+
+        // Owner and version ids were text and are now uuid: parseable values survive, unparseable ones are cleared
+        // and owners that point at nothing are repointed at the placeholder so the new foreign key holds.
+        Assert.Equal(new Guid(OwnerItemId), await ScalarAsync<Guid>(dataSource, $"""SELECT "OwnerId" FROM "BaseItems" WHERE "Id" = '{OwnedItemId}'""", cancellationToken));
+        Assert.Equal(new Guid(OwnerItemId), await ScalarAsync<Guid>(dataSource, $"""SELECT "PrimaryVersionId" FROM "BaseItems" WHERE "Id" = '{OwnedItemId}'""", cancellationToken));
+        Assert.Null(await NullableScalarAsync(dataSource, $"""SELECT "OwnerId" FROM "BaseItems" WHERE "Id" = '{UnparseableOwnerItemId}'""", cancellationToken));
+        Assert.Null(await NullableScalarAsync(dataSource, $"""SELECT "PrimaryVersionId" FROM "BaseItems" WHERE "Id" = '{UnparseableOwnerItemId}'""", cancellationToken));
+        Assert.Equal(new Guid(PlaceholderItemId), await ScalarAsync<Guid>(dataSource, $"""SELECT "OwnerId" FROM "BaseItems" WHERE "Id" = '{DanglingOwnerItemId}'""", cancellationToken));
+
+        // ExtraIds and OriginalLanguage are unrelated columns, so the extra ids must not have been carried over.
+        Assert.Null(await NullableScalarAsync(dataSource, $"""SELECT "OriginalLanguage" FROM "BaseItems" WHERE "Id" = '{UnparseableOwnerItemId}'""", cancellationToken));
+
+        // UserId is no longer nullable, so the rows that never had an owner had to be removed.
+        Assert.Equal(1L, await ScalarAsync<long>(dataSource, """SELECT count(*) FROM "Permissions" """, cancellationToken));
+        Assert.Equal(1L, await ScalarAsync<long>(dataSource, """SELECT count(*) FROM "Preferences" """, cancellationToken));
+
+        await AssertContextMatchesSchemaAsync(dataSource, cancellationToken);
+    }
+
+    [Fact]
+    public async Task LegacyDatabaseAndFreshInstall_EndUpWithTheSameSchema()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var freshConnectionString = await CreateDatabaseAsync("schema_fresh", cancellationToken);
+        var upgradedConnectionString = await CreateDatabaseAsync("schema_upgraded", cancellationToken);
+
+        await using var freshDataSource = new NpgsqlDataSourceBuilder(freshConnectionString).Build();
+        await MigrateAsync(freshDataSource, null, cancellationToken);
+
+        await using var upgradedDataSource = new NpgsqlDataSourceBuilder(upgradedConnectionString).Build();
+        await CreateLegacyDatabaseAsync(upgradedDataSource, cancellationToken);
+        await RunUpgradeInStartupOrderAsync(upgradedDataSource, cancellationToken);
+
+        Assert.Equal(
+            await DescribeColumnsAsync(freshDataSource, cancellationToken),
+            await DescribeColumnsAsync(upgradedDataSource, cancellationToken));
+        Assert.Equal(
+            await DescribeIndexesAsync(freshDataSource, cancellationToken),
+            await DescribeIndexesAsync(upgradedDataSource, cancellationToken));
+    }
+
+    [Fact]
+    public async Task UniqueUsernameIndex_CannotBeAppliedBeforeTheUsernameCodeMigration()
+    {
+        var cancellationToken = TestContext.Current.CancellationToken;
+        var connectionString = await CreateDatabaseAsync("username_index_order", cancellationToken);
+
+        await using var dataSource = new NpgsqlDataSourceBuilder(connectionString).Build();
+        await CreateLegacyDatabaseAsync(dataSource, cancellationToken);
+
+        // Every existing user starts out with the same empty normalized username, so the index can only be built once
+        // UpdateNormalizedUsername has filled the column in. That is why the index is a migration of its own.
+        await Assert.ThrowsAsync<PostgresException>(() => MigrateAsync(dataSource, null, cancellationToken));
+    }
+
+    private static JellyfinDbContext CreateContext(NpgsqlDataSource dataSource)
+    {
+        var optionsBuilder = new DbContextOptionsBuilder<JellyfinDbContext>();
+        var provider = new PostgreSqlDatabaseProvider(dataSource);
+        provider.Initialise(optionsBuilder, new DatabaseConfigurationOptions { DatabaseType = "PostgreSQL" });
+        return new JellyfinDbContext(
+            optionsBuilder.Options,
+            NullLogger<JellyfinDbContext>.Instance,
+            provider,
+            new NoLockBehavior(NullLogger<NoLockBehavior>.Instance));
+    }
+
+    private static async Task MigrateAsync(NpgsqlDataSource dataSource, string? targetMigration, CancellationToken cancellationToken)
+    {
+        var context = CreateContext(dataSource);
+        await using (context.ConfigureAwait(false))
+        {
+            await context.GetService<IMigrator>().MigrateAsync(targetMigration, cancellationToken).ConfigureAwait(false);
+        }
+    }
+
+    private static async Task<IReadOnlyList<string>> AppliedMigrationsAsync(NpgsqlDataSource dataSource, CancellationToken cancellationToken)
+    {
+        var context = CreateContext(dataSource);
+        await using (context.ConfigureAwait(false))
+        {
+            return [.. await context.Database.GetAppliedMigrationsAsync(cancellationToken).ConfigureAwait(false)];
+        }
+    }
+
+    private static async Task<IReadOnlyList<string>> PendingMigrationsAsync(NpgsqlDataSource dataSource, CancellationToken cancellationToken)
+    {
+        var context = CreateContext(dataSource);
+        await using (context.ConfigureAwait(false))
+        {
+            return [.. await context.Database.GetPendingMigrationsAsync(cancellationToken).ConfigureAwait(false)];
+        }
+    }
+
+    private static async Task ExecuteAsync(NpgsqlDataSource dataSource, string sql, CancellationToken cancellationToken)
+    {
+        await using var command = dataSource.CreateCommand(sql);
+        await command.ExecuteNonQueryAsync(cancellationToken).ConfigureAwait(false);
+    }
+
+    private static async Task<T> ScalarAsync<T>(NpgsqlDataSource dataSource, string sql, CancellationToken cancellationToken)
+    {
+        var value = await NullableScalarAsync(dataSource, sql, cancellationToken).ConfigureAwait(false);
+        Assert.NotNull(value);
+        return (T)value;
+    }
+
+    private static async Task<object?> NullableScalarAsync(NpgsqlDataSource dataSource, string sql, CancellationToken cancellationToken)
+    {
+        await using var command = dataSource.CreateCommand(sql);
+        var value = await command.ExecuteScalarAsync(cancellationToken).ConfigureAwait(false);
+        return value is null or DBNull ? null : value;
+    }
+
+    private static async Task<IReadOnlyList<string>> QueryLinesAsync(NpgsqlDataSource dataSource, string sql, CancellationToken cancellationToken)
+    {
+        var lines = new List<string>();
+        await using var command = dataSource.CreateCommand(sql);
+        await using var reader = await command.ExecuteReaderAsync(cancellationToken).ConfigureAwait(false);
+        while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
+        {
+            var values = new string[reader.FieldCount];
+            for (var i = 0; i < reader.FieldCount; i++)
+            {
+                values[i] = await reader.IsDBNullAsync(i, cancellationToken).ConfigureAwait(false)
+                    ? "<null>"
+                    : Convert.ToString(reader.GetValue(i), CultureInfo.InvariantCulture) ?? "<null>";
+            }
+
+            lines.Add(string.Join('|', values));
+        }
+
+        return lines;
+    }
+
+    private static Task<IReadOnlyList<string>> DescribeColumnsAsync(NpgsqlDataSource dataSource, CancellationToken cancellationToken)
+        => QueryLinesAsync(
+            dataSource,
+            """
+            SELECT table_name, column_name, data_type, is_nullable, coalesce(character_maximum_length, -1), coalesce(column_default, '')
+            FROM information_schema.columns
+            WHERE table_schema = 'public' AND table_name <> '__EFMigrationsHistory'
+            ORDER BY table_name, column_name
+            """,
+            cancellationToken);
+
+    private static Task<IReadOnlyList<string>> DescribeIndexesAsync(NpgsqlDataSource dataSource, CancellationToken cancellationToken)
+        => QueryLinesAsync(
+            dataSource,
+            """
+            SELECT tablename, indexname, indexdef
+            FROM pg_indexes
+            WHERE schemaname = 'public' AND tablename <> '__EFMigrationsHistory'
+            ORDER BY tablename, indexname
+            """,
+            cancellationToken);
+
+    /// <summary>
+    /// Builds a database that looks like one written by the previous build: only the baseline migration applied, and
+    /// data that only the old column types could hold.
+    /// </summary>
+    private static async Task CreateLegacyDatabaseAsync(NpgsqlDataSource dataSource, CancellationToken cancellationToken)
+    {
+        await MigrateAsync(dataSource, BaselineMigrationId, cancellationToken).ConfigureAwait(false);
+
+        await ExecuteAsync(
+            dataSource,
+            $"""
+            INSERT INTO "Users" ("Id", "Username", "MustUpdatePassword", "AuthenticationProviderId", "PasswordResetProviderId",
+                "InvalidLoginAttemptCount", "MaxActiveSessions", "SubtitleMode", "PlayDefaultAudioTrack", "DisplayMissingEpisodes",
+                "DisplayCollectionsView", "EnableLocalPassword", "HidePlayedInLatest", "RememberAudioSelections",
+                "RememberSubtitleSelections", "EnableNextEpisodeAutoPlay", "EnableAutoLogin", "EnableUserPreferenceAccess",
+                "InternalId", "SyncPlayAccess", "RowVersion")
+            VALUES
+                ('{AliceId}', 'alice', false, 'provider', 'provider', 0, 0, 0, true, false, true, false, false, true, true, true, false, true, 1, 0, 0),
+                ('{BobId}', 'bob', false, 'provider', 'provider', 0, 0, 0, true, false, true, false, false, true, true, true, false, true, 2, 0, 0);
+
+            INSERT INTO "BaseItems" ("Id", "Type", "IsMovie", "IsLocked", "IsSeries", "IsRepeat", "IsInMixedFolder",
+                "IsFolder", "IsVirtualItem", "Name", "Path", "OwnerId", "PrimaryVersionId", "ExtraIds")
+            VALUES
+                ('{OwnerItemId}', 'MediaBrowser.Controller.Entities.Movies.Movie', true, false, false, false, false, false, false, 'Owner', '/media/owner.mkv', NULL, NULL, NULL),
+                ('{OwnedItemId}', 'MediaBrowser.Controller.Entities.Video', false, false, false, false, false, false, false, 'Trailer', '/media/owner-trailer.mkv', '11111111111111111111111111111111', '11111111-1111-1111-1111-111111111111', NULL),
+                ('{UnparseableOwnerItemId}', 'MediaBrowser.Controller.Entities.Video', false, false, false, false, false, false, false, 'Junk', '/media/junk.mkv', '', '00000000-0000-0000-0000-000000000000', 'aaaa|bbbb'),
+                ('{DanglingOwnerItemId}', 'MediaBrowser.Controller.Entities.Video', false, false, false, false, false, false, false, 'Dangling', '/media/dangling.mkv', '99999999-9999-9999-9999-999999999999', NULL, NULL);
+
+            INSERT INTO "Permissions" ("UserId", "Kind", "Value", "RowVersion")
+            VALUES ('{AliceId}', 0, true, 0), (NULL, 0, true, 0);
+
+            INSERT INTO "Preferences" ("UserId", "Kind", "Value", "RowVersion")
+            VALUES ('{BobId}', 0, 'kept', 0), (NULL, 0, 'orphaned', 0);
+            """,
+            cancellationToken).ConfigureAwait(false);
+    }
+
+    /// <summary>
+    /// Runs the migrations in the order the startup migration service picks them: schema and code migration ids are
+    /// sorted into one list, which puts the username code migration between the two schema migrations.
+    /// </summary>
+    private static async Task RunUpgradeInStartupOrderAsync(NpgsqlDataSource dataSource, CancellationToken cancellationToken)
+    {
+        await MigrateAsync(dataSource, SchemaUpgradeMigrationId, cancellationToken).ConfigureAwait(false);
+        await new UpdateNormalizedUsername(new SingleContextFactory(dataSource)).PerformAsync(cancellationToken).ConfigureAwait(false);
+        await MigrateAsync(dataSource, UsernameIndexMigrationId, cancellationToken).ConfigureAwait(false);
+    }
+
+    private static async Task AssertServer12SchemaAsync(NpgsqlDataSource dataSource, CancellationToken cancellationToken)
+    {
+        Assert.Equal("character varying", await ColumnTypeAsync(dataSource, "Users", "NormalizedUsername", cancellationToken).ConfigureAwait(false));
+        Assert.Equal("uuid", await ColumnTypeAsync(dataSource, "BaseItems", "OwnerId", cancellationToken).ConfigureAwait(false));
+        Assert.Equal("uuid", await ColumnTypeAsync(dataSource, "BaseItems", "PrimaryVersionId", cancellationToken).ConfigureAwait(false));
+        Assert.Equal("text", await ColumnTypeAsync(dataSource, "BaseItems", "OriginalLanguage", cancellationToken).ConfigureAwait(false));
+        Assert.Equal("boolean", await ColumnTypeAsync(dataSource, "MediaStreamInfos", "IsOriginal", cancellationToken).ConfigureAwait(false));
+        Assert.Null(await ColumnTypeAsync(dataSource, "BaseItems", "ExtraIds", cancellationToken).ConfigureAwait(false));
+        Assert.Null(await ColumnTypeAsync(dataSource, "Permissions", "Permission_Permissions_Guid", cancellationToken).ConfigureAwait(false));
+        Assert.Null(await ColumnTypeAsync(dataSource, "Preferences", "Preference_Preferences_Guid", cancellationToken).ConfigureAwait(false));
+
+        Assert.Equal("NO", await ScalarAsync<string>(
+            dataSource,
+            """SELECT is_nullable FROM information_schema.columns WHERE table_name = 'Permissions' AND column_name = 'UserId'""",
+            cancellationToken).ConfigureAwait(false));
+        Assert.Equal("NO", await ScalarAsync<string>(
+            dataSource,
+            """SELECT is_nullable FROM information_schema.columns WHERE table_name = 'Preferences' AND column_name = 'UserId'""",
+            cancellationToken).ConfigureAwait(false));
+
+        Assert.True(await ScalarAsync<bool>(
+            dataSource,
+            """SELECT indisunique FROM pg_index WHERE indexrelid = 'public."IX_Users_NormalizedUsername"'::regclass""",
+            cancellationToken).ConfigureAwait(false));
+
+        // The model declares no database defaults, so none may be left over from filling the new columns in.
+        Assert.Equal(0L, await ScalarAsync<long>(
+            dataSource,
+            """
+            SELECT count(*) FROM information_schema.columns
+            WHERE table_schema = 'public' AND column_default IS NOT NULL
+              AND (table_name, column_name) IN (
+                  ('Users', 'NormalizedUsername'), ('Permissions', 'UserId'),
+                  ('Preferences', 'UserId'), ('MediaStreamInfos', 'IsOriginal'))
+            """,
+            cancellationToken).ConfigureAwait(false));
+
+        // Playlists may hold the same child more than once, which the primary key has to allow for.
+        Assert.Equal(
+            "ParentId,SortOrder",
+            await ScalarAsync<string>(
+                dataSource,
+                """
+                SELECT string_agg(attribute.attname, ',' ORDER BY key.ordinality)
+                FROM pg_constraint AS constraint_
+                CROSS JOIN LATERAL unnest(constraint_.conkey) WITH ORDINALITY AS key(attnum, ordinality)
+                JOIN pg_attribute AS attribute
+                  ON attribute.attrelid = constraint_.conrelid AND attribute.attnum = key.attnum
+                WHERE constraint_.conname = 'PK_LinkedChildren'
+                """,
+                cancellationToken).ConfigureAwait(false));
+
+        Assert.Equal(1L, await ScalarAsync<long>(
+            dataSource,
+            """SELECT count(*) FROM pg_constraint WHERE conname = 'FK_BaseItems_BaseItems_OwnerId'""",
+            cancellationToken).ConfigureAwait(false));
+    }
+
+    private static async Task<string?> ColumnTypeAsync(NpgsqlDataSource dataSource, string table, string column, CancellationToken cancellationToken)
+    {
+        var value = await NullableScalarAsync(
+            dataSource,
+            $"""SELECT data_type FROM information_schema.columns WHERE table_schema = 'public' AND table_name = '{table}' AND column_name = '{column}'""",
+            cancellationToken).ConfigureAwait(false);
+        return (string?)value;
+    }
+
+    /// <summary>
+    /// Writes and reads an entity through the context to prove the migrated schema really matches the current model.
+    /// </summary>
+    private static async Task AssertContextMatchesSchemaAsync(NpgsqlDataSource dataSource, CancellationToken cancellationToken)
+    {
+        var context = CreateContext(dataSource);
+        await using (context.ConfigureAwait(false))
+        {
+            Assert.False(context.Database.HasPendingModelChanges());
+
+            var user = new User("carol", "provider", "provider");
+            context.Users.Add(user);
+            await context.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
+
+            var reloaded = await context.Users.AsNoTracking()
+                .FirstAsync(u => u.Id.Equals(user.Id), cancellationToken)
+                .ConfigureAwait(false);
+            Assert.Equal("CAROL", reloaded.NormalizedUsername);
+        }
+    }
+
+    private async Task<string> CreateDatabaseAsync(string name, CancellationToken cancellationToken)
+    {
+        await using var adminDataSource = new NpgsqlDataSourceBuilder(_container.GetConnectionString()).Build();
+        await ExecuteAsync(adminDataSource, $"CREATE DATABASE {name}", cancellationToken).ConfigureAwait(false);
+
+        return new NpgsqlConnectionStringBuilder(_container.GetConnectionString()) { Database = name }.ConnectionString;
+    }
+
+    private sealed class SingleContextFactory : IDbContextFactory<JellyfinDbContext>
+    {
+        private readonly NpgsqlDataSource _dataSource;
+
+        public SingleContextFactory(NpgsqlDataSource dataSource)
+        {
+            _dataSource = dataSource;
+        }
+
+        public JellyfinDbContext CreateDbContext() => CreateContext(_dataSource);
+    }
+}