Add UseStorageUnsafe for backward compatibility reasons

Author: odinserj

src/Hangfire.Core/GlobalConfiguration.cs

@@ -66,17 +66,7 @@ public GlobalConfiguration()
 
             RegisterService<ILogProvider>(LogProvider.ResolveLogProvider());
             RegisterService<JobActivator>(new JobActivator());
-            RegisterService<JobStorage>(static () =>
-            {
-                throw new InvalidOperationException(
-                    "Current JobStorage instance has not been initialized yet. You must set it before using Hangfire Client or Server API. " +
-#if NET45 || NET46
-                    "For NET Framework applications please use GlobalConfiguration.Configuration.UseXXXStorage method, where XXX is the storage type, like `UseSqlServerStorage`."
-#else
-                    "For .NET Core applications please call the `IServiceCollection.AddHangfire` extension method from Hangfire.NetCore or Hangfire.AspNetCore package depending on your application type when configuring the services and ensure service-based APIs are used instead of static ones, like `IBackgroundJobClient` instead of `BackgroundJob` and `IRecurringJobManager` instead of `RecurringJob`."
-#endif
-                );
-            });
+            RegisterUninitializedStorage();
         }
 
         public GlobalConfiguration(GlobalConfiguration configuration)
@@ -110,6 +100,21 @@ public T ResolveService<T>()
 
             return (T)service.Key(service.Value);
         }
+
+        internal void RegisterUninitializedStorage()
+        {
+            RegisterService<JobStorage>(static () =>
+            {
+                throw new InvalidOperationException(
+                    "Current JobStorage instance has not been initialized yet. You must set it before using Hangfire Client or Server API. " +
+#if NET45 || NET46
+                    "For NET Framework applications please use GlobalConfiguration.Configuration.UseXXXStorage method, where XXX is the storage type, like `UseSqlServerStorage`."
+#else
+                    "For .NET Core applications please call the `IServiceCollection.AddHangfire` extension method from Hangfire.NetCore or Hangfire.AspNetCore package depending on your application type when configuring the services and ensure service-based APIs are used instead of static ones, like `IBackgroundJobClient` instead of `BackgroundJob` and `IRecurringJobManager` instead of `RecurringJob`."
+#endif
+                );
+            });
+        }
     }
 
     public static class CompatibilityLevelExtensions

src/Hangfire.Core/GlobalConfigurationExtensions.cs

@@ -42,6 +42,23 @@ public static IGlobalConfiguration<TStorage> UseStorage<TStorage>(
             return configuration.Use(storage, entryAction: null);
         }
 
+        [Obsolete("Compatibility workaround for setting null values in JobStorage.Current. Should be removed in 2.0.0.")]
+        internal static void UseStorageUnsafe<TStorage>(
+            [NotNull] this IGlobalConfiguration configuration,
+            [CanBeNull] TStorage? storage)
+            where TStorage : JobStorage
+        {
+            if (configuration == null) throw new ArgumentNullException(nameof(configuration));
+
+            if (storage == null)
+            {
+                GetTopLevelConfiguration(configuration).RegisterUninitializedStorage();
+                return;
+            }
+
+            configuration.RegisterService<JobStorage>(storage);
+        }
+
         public static IGlobalConfiguration<TStorage> WithJobExpirationTimeout<TStorage>(
             [NotNull] this IGlobalConfiguration<TStorage> configuration,
             TimeSpan timeout)

src/Hangfire.Core/JobStorage.cs

@@ -34,7 +34,7 @@ public static JobStorage Current
             get => GlobalConfiguration.Configuration.ResolveService<JobStorage>();
 
             [Obsolete]
-            set => GlobalConfiguration.Configuration.UseStorage(value);
+            set => GlobalConfiguration.Configuration.UseStorageUnsafe(value);
         }
 
         public TimeSpan JobExpirationTimeout