From 08e4269495d523d9552d06f3e5702c1889d6a70d Mon Sep 17 00:00:00 2001
From: David Fowler <davidfowl@gmail.com>
Date: Wed, 7 Apr 2021 09:20:14 -0700
Subject: [PATCH] Disposing scopes more than once should work - Recently
 introduced a regression where disposing DI scopes multiple times throws.

---
 .../src/ServiceLookup/ServiceProviderEngineScope.cs    |  6 ++++++
 .../tests/DI.Tests/ServiceProviderEngineScopeTests.cs  | 10 ++++++++++
 2 files changed, 16 insertions(+)

diff --git a/src/libraries/Microsoft.Extensions.DependencyInjection/src/ServiceLookup/ServiceProviderEngineScope.cs b/src/libraries/Microsoft.Extensions.DependencyInjection/src/ServiceLookup/ServiceProviderEngineScope.cs
index 656cf9b10c4f1f..b29b4016bc0f5b 100644
--- a/src/libraries/Microsoft.Extensions.DependencyInjection/src/ServiceLookup/ServiceProviderEngineScope.cs
+++ b/src/libraries/Microsoft.Extensions.DependencyInjection/src/ServiceLookup/ServiceProviderEngineScope.cs
@@ -176,6 +176,12 @@ private void ClearState()
             // try to return to the pool while somebody is trying to access ResolvedServices.
             lock (_scopeLock)
             {
+                // Don't attempt to dispose if we're already disposed
+                if (_state == null)
+                {
+                    return;
+                }
+
                 // ResolvedServices is never cleared for singletons because there might be a compilation running in background
                 // trying to get a cached singleton service. If it doesn't find it
                 // it will try to create a new one which will result in an ObjectDisposedException.
diff --git a/src/libraries/Microsoft.Extensions.DependencyInjection/tests/DI.Tests/ServiceProviderEngineScopeTests.cs b/src/libraries/Microsoft.Extensions.DependencyInjection/tests/DI.Tests/ServiceProviderEngineScopeTests.cs
index ae36f2e1d64bba..223c6bfd7bc8a9 100644
--- a/src/libraries/Microsoft.Extensions.DependencyInjection/tests/DI.Tests/ServiceProviderEngineScopeTests.cs
+++ b/src/libraries/Microsoft.Extensions.DependencyInjection/tests/DI.Tests/ServiceProviderEngineScopeTests.cs
@@ -21,6 +21,16 @@ public void ResolvedServicesAfterDispose_ThrowsObjectDispose()
             Assert.Throws<ObjectDisposedException>(() => serviceProviderEngineScope.ResolvedServices);
         }
 
+        [Fact]
+        public void DoubleDisposeWorks()
+        {
+            var engine = new FakeEngine();
+            var serviceProviderEngineScope = new ServiceProviderEngineScope(engine);
+            serviceProviderEngineScope.ResolvedServices.Add(new ServiceCacheKey(typeof(IFakeService), 0), null);
+            serviceProviderEngineScope.Dispose();
+            serviceProviderEngineScope.Dispose();
+        }
+
         private class FakeEngine : ServiceProviderEngine
         {
             public FakeEngine() :