InitializersMiddleware swallows an exception from any pipeline initializer, skips the remaining pipelines and never retries: friendly URLs 404 and items load null until the next restart

[Justinvolved]

Describe the bug

Dynamicweb.Host.Core.Middleware.InitializersMiddleware.Invoke runs RunInitializers() on every registered IPipeline in rank order inside one try { ... } catch (Exception) { } with an empty catch, then sets _wasInvoked = true. If one initializer throws, every pipeline after it in rank order is skipped, nothing is logged, and the middleware never runs them again until the application restarts.

ClassicFrontendPipeline has Rank = int.MaxValue, so it always runs last. Its RunInitializers calls ItemManager.Initialize(), UrlPageTreeHelper.Instance.BuildPageUrlTree() and UrlIndex.BuildIndexes(). Any add-in pipeline with a lower rank whose initializer throws once (for example a database timeout during start-up) therefore leaves the whole frontend without item types and URL index for the lifetime of the process:

• every friendly URL returns 404,
• Default.aspx?ID=<page> renders an empty shell,
• item-based paragraph templates throw NullReferenceException on Model.Item,

with no log entry that names the cause. A restart fixes it, which makes the outage easy to blame on the last content change.

To Reproduce

1. Install an add-in that registers an IPipeline with Rank below int.MaxValue whose RunInitializers() throws (in the case observed, an add-in start-up SQL statement hit Execution Timeout Expired).
2. Restart the application and request any page.

Observed

On a DW 10.29.4 solution, one application start hit a timeout in an add-in initializer (rank 0):

2026-09-22 08:03:08.7835: INSERT INTO McpConfigurationCredential (...) SELECT ... FROM McpConfiguration c WHERE ... NOT EXISTS (...).
Microsoft.Data.SqlClient.SqlException (0x80131904): Execution Timeout Expired.
   at Dynamicweb.Data.Database.ExecuteNonQuery(IDbCommand command)

From that start until a manual recycle about 90 minutes later: every friendly URL in the webshop areas returned 404, Default.aspx?ID=<page> rendered an empty shell, and each request to / logged 17 NullReferenceExceptions in Swift paragraph templates whose only dereference is Model.Item. The item-manager start-up log line that appears at every other start (two or more xml-files which contains items with same system name, written during ItemManager.Initialize) was missing for that start only. Nothing logged the skipped initialization.

Source (decompiled, identical in Dynamicweb.Host.Core 10.28.11 and 10.29.4):

UpdateManager.ExecuteUpdates();
await context.RequestServices.GetRequiredService<CloudHostingManager>().HandleRingChange();
try
{
    foreach (IPipeline pipeline in _pipelines)   // ordered by Rank
    {
        pipeline.RunInitializers();
    }
}
catch (Exception)
{
}
_wasInvoked = true;

Dynamicweb.Frontend.Classic.ClassicFrontendPipeline: Rank { get; } = int.MaxValue; RunInitializers() calls ItemManager.Initialize(); UrlPageTreeHelper.Instance.BuildPageUrlTree(); UrlIndex.BuildIndexes();.

Expected behavior

• Each pipeline's RunInitializers() runs in its own try/catch, so one failing add-in does not prevent the platform's own initializers from running.
• The exception is logged with the pipeline type name.
• Optionally, a failed initializer is retried on a later request instead of being marked done.

Environment

• Dynamicweb 10.29.4 (observed), same code in 10.28.11 (.NET 10 hosting)
• Add-in: an MCP add-in build whose initializer ran unguarded inside RunInitializers (the current 0.6.0-BETA build guards and logs its own start-up, so it no longer triggers this; the platform behaviour is unchanged)