Revert behavior for non SnapShot scenario to throw an exception when initialization fails (#1884)

Author: normj

.autover/changes/cd8cd757-830a-4abd-b01f-92176e837b07.json

@@ -0,0 +1,11 @@
+{
+  "Projects": [
+    {
+      "Name": "Amazon.Lambda.RuntimeSupport",
+      "Type": "Patch",
+      "ChangelogMessages": [
+        "Revert behavior for non SnapShot scenario to throw an exception when initialization fails"
+      ]
+    }
+  ]
+}

Libraries/src/Amazon.Lambda.RuntimeSupport/Bootstrap/LambdaBootstrap.cs

@@ -219,8 +219,8 @@ internal async Task<bool> InitializeAsync()
                     System.Environment.Exit(1); // This needs to be non-zero for Lambda Sandbox to know that Runtime client encountered an exception
                 }
 #endif
+                throw;
             }
-            return false;
         }
 
         internal async Task InvokeOnceAsync(CancellationToken cancellationToken = default)

Libraries/test/Amazon.Lambda.RuntimeSupport.Tests/Amazon.Lambda.RuntimeSupport.UnitTests/LambdaBootstrapTests.cs

@@ -83,14 +83,23 @@ public async Task NoInitializer()
         }
 
         [Fact]
-        public async Task InitializerHandlesExceptionsGracefully()
+        public async Task InitializerHandlesExceptions()
         {
+            bool exceptionThrown = false;
             using (var bootstrap = new LambdaBootstrap(_testFunction.BaseHandlerAsync, _testInitializer.InitializeThrowAsync))
             {
                 bootstrap.Client = _testRuntimeApiClient;
-                await bootstrap.RunAsync();
+                try
+                {
+                    await bootstrap.RunAsync();
+                }
+                catch
+                {
+                    exceptionThrown = true;
+                }
             }
 
+            Assert.True(exceptionThrown);
             Assert.True(_testRuntimeApiClient.ReportInitializationErrorAsyncExceptionCalled);
             Assert.True(_testInitializer.InitializerWasCalled);
             Assert.False(_testFunction.HandlerWasCalled);