Fix thread CultureInfo issue breaking PetaPoco

src/Umbraco.Web/Security/Identity/AppBuilderExtensions.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
+using System.Threading;
 using System.Web;
 using Microsoft.AspNet.Identity;
 using Microsoft.AspNet.Identity.Owin;
@@ -191,5 +193,48 @@ namespace Umbraco.Web.Security.Identity
         }
         #endregion
 
+        public static void SanitizeThreadCulture(this IAppBuilder app)
+        {
+            // get the current culture
+            var currentCulture = CultureInfo.CurrentCulture;
+
+            // at the top of any culture should be the invariant culture - find it
+            // doing an .Equals comparison ensure that we *will* find it and not loop
+            // endlessly
+            var invariantCulture = currentCulture;
+            while (invariantCulture.Equals(CultureInfo.InvariantCulture) == false)
+                invariantCulture = invariantCulture.Parent;
+
+            // now that invariant culture should be the same object as CultureInfo.InvariantCulture
+            // yet for some reasons, sometimes it is not - and this breaks anything that loops on
+            // culture.Parent until a reference equality to CultureInfo.InvariantCulture. See, for
+            // example, the following code in PerformanceCounterLib.IsCustomCategory:
+            //
+            // CultureInfo culture = CultureInfo.CurrentCulture;
+            // while (culture != CultureInfo.InvariantCulture)
+            // {
+            //     library = GetPerformanceCounterLib(machine, culture);
+            //     if (library.IsCustomCategory(category))
+            //         return true;
+            //     culture = culture.Parent;
+            // }
+            //
+            // The reference comparisons never succeeds, hence the loop never ends, and the
+            // application hangs.
+            //
+            // granted, that comparison should probably be a .Equals comparison, but who knows
+            // how many times the framework assumes that it can do a reference comparison? So,
+            // better fix the cultures.
+
+            if (ReferenceEquals(invariantCulture, CultureInfo.InvariantCulture))
+                return;
+
+            // if we do not have equality, fix cultures by replacing them with a culture with
+            // the same name, but obtained here and now, with a proper invariant top culture
+
+            var thread = Thread.CurrentThread;
+            thread.CurrentCulture = CultureInfo.GetCultureInfo(thread.CurrentCulture.Name);
+            thread.CurrentUICulture = CultureInfo.GetCultureInfo(thread.CurrentUICulture.Name);
+        }
     }
 }

src/Umbraco.Web/UmbracoDefaultOwinStartup.cs

@@ -21,6 +21,8 @@ namespace Umbraco.Web
     {
         public virtual void Configuration(IAppBuilder app)
         {
+            app.SanitizeThreadCulture();
+
             app.SetUmbracoLoggerFactory();
 
             //Configure the Identity user manager for use with Umbraco Back office